Pathogens

14 pages, 2191 KB

Open AccessEditor’s ChoiceArticle

Adenovirus-vectored African Swine Fever Virus Antigens Cocktail Is Not Protective against Virulent Arm07 Isolate in Eurasian Wild Boar

by Estefanía Cadenas-Fernández, Jose M. Sánchez-Vizcaíno, Aleksandra Kosowska, Belén Rivera, Francisco Mayoral-Alegre, Antonio Rodríguez-Bertos, Jianxiu Yao, Jocelyn Bray, Shehnaz Lokhandwala, Waithaka Mwangi and Jose A. Barasona

Pathogens 2020, 9(3), 171; https://doi.org/10.3390/pathogens9030171 - 28 Feb 2020

Cited by 51 | Viewed by 5224

Abstract

African swine fever (ASF) is a viral disease of domestic and wild suids for which there is currently no vaccine or treatment available. The recent spread of ASF virus (ASFV) through Europe and Asia is causing enormous economic and animal losses. Unfortunately, the [...] Read more.

African swine fever (ASF) is a viral disease of domestic and wild suids for which there is currently no vaccine or treatment available. The recent spread of ASF virus (ASFV) through Europe and Asia is causing enormous economic and animal losses. Unfortunately, the measures taken so far are insufficient and an effective vaccine against ASFV needs to be urgently developed. We hypothesized that immunization with a cocktail of thirty-five rationally selected antigens would improve the protective efficacy of subunit vaccine prototypes given that the combination of fewer immunogenic antigens (between 2 and 22) has failed to elicit protective efficacy. To this end, immunogenicity and efficacy of thirty-five adenovirus-vectored ASFV antigens were evaluated in wild boar. The treated animals were divided into different groups to test the use of BioMize adjuvant and different inoculation strategies. Forty-eight days after priming, the nine treated and two control wild boar were challenged with the virulent ASFV Arm07 isolate. All animals showed clinical signs and pathological findings consistent with ASF. This lack of protection is in line with other studies with subunit vaccine prototypes, demonstrating that there is still much room for improvement to obtain an effective subunit ASFV vaccine. Full article

(This article belongs to the Special Issue African Swine Fever Virus Infection)

► Show Figures

Figure 1

13 pages, 3574 KB

Open AccessEditor’s ChoiceArticle

Zika Virus-Induction of the Suppressor of Cytokine Signaling 1/3 Contributes to the Modulation of Viral Replication

by Rak-Kyun Seong, Jae Kyung Lee and Ok Sarah Shin

Pathogens 2020, 9(3), 163; https://doi.org/10.3390/pathogens9030163 - 27 Feb 2020

Cited by 33 | Viewed by 4085

Abstract

Zika virus (ZIKV) is a mosquito-borne flavivirus that has emerged and caused global outbreaks since 2007. Although ZIKV proteins have been shown to suppress early anti-viral innate immune responses, little is known about the exact mechanisms. This study demonstrates that infection with either [...] Read more.

Zika virus (ZIKV) is a mosquito-borne flavivirus that has emerged and caused global outbreaks since 2007. Although ZIKV proteins have been shown to suppress early anti-viral innate immune responses, little is known about the exact mechanisms. This study demonstrates that infection with either the African or Asian lineage of ZIKV leads to a modulated expression of suppressor of cytokine signaling (SOCS) genes encoding SOCS1 and SOCS3 in the following cell models: A549 human lung adenocarcinoma cells; JAr human choriocarcinoma cells; human neural progenitor cells. Studies of viral gene expression in response to SOCS1 or SOCS3 demonstrated that the knockdown of these SOCS proteins inhibited viral NS5 or ZIKV RNA expression, whereas overexpression resulted in an increased expression. Moreover, the overexpression of SOCS1 or SOCS3 inhibited the retinoic acid-inducible gene-I-like receptor-mediated activation of both type I and III interferon pathways. These results imply that SOCS upregulation following ZIKV infection modulates viral replication, possibly via the regulation of anti-viral innate immune responses. Full article

(This article belongs to the Special Issue Current Advances in Flavivirus Research)

► Show Figures

Figure 1

23 pages, 1585 KB

Open AccessEditor’s ChoiceReview

Orthohepevirus C: An Expanding Species of Emerging Hepatitis E Virus Variants

by Bo Wang, Dominik Harms, Xing-Lou Yang and C.-Thomas Bock

Pathogens 2020, 9(3), 154; https://doi.org/10.3390/pathogens9030154 - 25 Feb 2020

Cited by 54 | Viewed by 5140

Abstract

Hepatitis E virus (HEV) is an emerging zoonotic pathogen that has received an increasing amount of attention from virologists, clinicians, veterinarians, and epidemiologists over the past decade. The host range and animal reservoirs of HEV are rapidly expanding and a plethora of emerging [...] Read more.

Hepatitis E virus (HEV) is an emerging zoonotic pathogen that has received an increasing amount of attention from virologists, clinicians, veterinarians, and epidemiologists over the past decade. The host range and animal reservoirs of HEV are rapidly expanding and a plethora of emerging HEV variants have been recently identified, some of which have the potential for interspecies infection. In this review, the detection of genetically diverse HEV variants, classified into and presumably associated with the species Orthohepevirus C, currently comprising HEV genotypes C1 and C2, by either serological or molecular approach is summarized. The distribution, genomic variability, and evolution of Orthohepevirus C are analyzed. Moreover, the potential risk of cross-species infection and zoonotic transmission of Orthohepevirus C are discussed. Full article

(This article belongs to the Special Issue Hepatitis E Virus (HEV) Infections)

► Show Figures

Figure 1

16 pages, 3026 KB

Open AccessEditor’s ChoiceArticle

Isolation of Acanthamoeba T5 from Water: Characterization of Its Pathogenic Potential, Including the Production of Extracellular Vesicles

by Lissette Retana Moreira, Daniel Vargas Ramírez, Fátima Linares, Alexa Prescilla Ledezma, Annette Vaglio Garro, Antonio Osuna, Jacob Lorenzo Morales and Elizabeth Abrahams Sandí

Pathogens 2020, 9(2), 144; https://doi.org/10.3390/pathogens9020144 - 21 Feb 2020

Cited by 17 | Viewed by 5427

Abstract

Acanthamoeba is a genus of free-living amoebae widely distributed in nature, associated with the development of encephalitis and keratitis. Despite the fact that it is common to find genotype T5 in environmental samples, only a few cases have been associated with clinical cases [...] Read more.

Acanthamoeba is a genus of free-living amoebae widely distributed in nature, associated with the development of encephalitis and keratitis. Despite the fact that it is common to find genotype T5 in environmental samples, only a few cases have been associated with clinical cases in humans. The wide distribution of Acanthamoeba, the characteristic of being amphizoic and the severity of the disease motivate researchers to focus on the isolation of these organisms, but also in demonstrating direct and indirect factors that could indicate a possible pathogenic potential. Here, we performed the characterization of the pathogenic potential of an Acanthamoeba T5 isolate collected from a water source in a hospital. Osmo- and thermotolerance, the secretion of proteases and the effect of trophozoites over cell monolayers were analyzed by different methodologies. Additionally, we confirm the secretion of extracellular vesicles (EVs) of this isolate incubated at two different temperatures, and the presence of serine and cysteine proteases in these vesicles. Finally, using atomic force microscopy, we determined some nanomechanical properties of the secreted vesicles and found a higher value of adhesion in the EVs obtained at 37 °C, which could have implications in the parasite´s survival and damaging potential in two different biological environments. Full article

(This article belongs to the Special Issue Selected Papers from the International Meeting on the Biology and Pathogenicity of Free-Living Amoebae (FLAM2019))

► Show Figures

Graphical abstract

20 pages, 3561 KB

Open AccessEditor’s ChoiceArticle

Recognition of Lipoproteins by Toll-like Receptor 2 and DNA by the AIM2 Inflammasome Is Responsible for Production of Interleukin-1β by Virulent Suilysin-Negative Streptococcus suis Serotype 2

by Agustina Lavagna, Jean-Philippe Auger, Stephen E. Giradin, Nicolas Gisch, Mariela Segura and Marcelo Gottschalk

Pathogens 2020, 9(2), 147; https://doi.org/10.3390/pathogens9020147 - 21 Feb 2020

Cited by 12 | Viewed by 4274

Abstract

Streptococcus suis serotype 2 is an important porcine bacterial pathogen and zoonotic agent causing sudden death, septic shock and meningitis. These pathologies are the consequence of an exacerbated inflammatory response composed of various mediators including interleukin (IL)-1β. Elevated levels of the toxin suilysin [...] Read more.

Streptococcus suis serotype 2 is an important porcine bacterial pathogen and zoonotic agent causing sudden death, septic shock and meningitis. These pathologies are the consequence of an exacerbated inflammatory response composed of various mediators including interleukin (IL)-1β. Elevated levels of the toxin suilysin (SLY) were demonstrated to play a key role in S. suis-induced IL-1β production. However, 95% of serotype 2 strains isolated from diseased pigs in North America, many of which are virulent, do not produce SLY. In this study, we demonstrated that SLY-negative S. suis induces elevated levels of IL-1β in systemic organs, with dendritic cells contributing to this production. SLY-negative S. suis-induced IL-1β production requires MyD88 and TLR2 following recognition of lipoproteins. However, the higher internalization rate of the SLY-negative strain results in intracellularly located DNA being recognized by the AIM2 inflammasome, which promotes IL-1β production. Finally, the role of IL-1 in host survival during the S. suis systemic infection is beneficial and conserved, regardless of SLY production, via modulation of the inflammation required to control bacterial burden. In conclusion, this study demonstrates that SLY is not required for S. suis-induced IL-1β production. Full article

(This article belongs to the Special Issue Update on Streptococcus suis Research and Prevention in the Era of Antibiotic Restriction - 4th International Workshop on Streptococcus suis)

► Show Figures

Figure 1

11 pages, 957 KB

Open AccessEditor’s ChoiceArticle

Comprehensive Evaluation of Hepatitis E Serology and Molecular Testing in a Large Cohort

by Olympia E. Anastasiou, Viktoria Thodou, Annemarie Berger, Heiner Wedemeyer and Sandra Ciesek

Pathogens 2020, 9(2), 137; https://doi.org/10.3390/pathogens9020137 - 19 Feb 2020

Cited by 16 | Viewed by 4217

Abstract

Introduction: Reliable and cost-effective diagnostics for hepatitis E virus (HEV) infection are necessary. The aim of our study was to investigate which diagnostic test is most accurate to detect HEV infection in immunocompetent and immunosuppressed patients in a real world setting. Patients and [...] Read more.

Introduction: Reliable and cost-effective diagnostics for hepatitis E virus (HEV) infection are necessary. The aim of our study was to investigate which diagnostic test is most accurate to detect HEV infection in immunocompetent and immunosuppressed patients in a real world setting. Patients and Methods: We performed a retrospective analysis of 1165 patients tested for HEV antibodies and HEV PCR at the same time point. Clinical, laboratory and virological data were taken from patient charts. HEV IgA was measured in a subgroup of 185 patients. Results: HEV RNA was detectable in 61 patients (5.2%); most of them (n = 49, 80.3%/n = 43, 70.5%) were HEV IgM+ and IgG+; however, 12 patients (19.6%) were HEV RNA positive/HEV IgM negative and 17 patients (27.8%) were HEV RNA positive/HEV IgG negative. Ten HEV RNA positive patients (16.4%) had neither HEV IgG nor IgM antibodies. Importantly, all of them were immunosuppressed. HEV IgA testing was less sensitive than HEV IgM for HEV diagnosis. Conclusions: HEV infection can be overlooked in patients without HEV specific antibodies. Performing PCR is necessary to diagnose or exclude HEV infection in immunocompromised hosts. In immunocompetent patients, a screening based on HEV antibodies (IgG/IgM) is sufficient. Full article

(This article belongs to the Special Issue Hepatitis E Virus (HEV) Infections)

► Show Figures

Figure 1

21 pages, 1467 KB

Open AccessEditor’s ChoiceReview

Host Factors Affecting Generation of Immunity Against Porcine Epidemic Diarrhea Virus in Pregnant and Lactating Swine and Passive Protection of Neonates

by Stephanie N. Langel, Qiuhong Wang, Anastasia N. Vlasova and Linda J. Saif

Pathogens 2020, 9(2), 130; https://doi.org/10.3390/pathogens9020130 - 18 Feb 2020

Cited by 43 | Viewed by 12292

Abstract

Porcine epidemic diarrhea virus (PEDV) is a highly virulent re-emerging enteric coronavirus that causes acute diarrhea, dehydration, and up to 100% mortality in neonatal suckling piglets. Despite this, a safe and effective PEDV vaccine against highly virulent strains is unavailable, making PEDV prevention [...] Read more.

Porcine epidemic diarrhea virus (PEDV) is a highly virulent re-emerging enteric coronavirus that causes acute diarrhea, dehydration, and up to 100% mortality in neonatal suckling piglets. Despite this, a safe and effective PEDV vaccine against highly virulent strains is unavailable, making PEDV prevention and control challenging. Lactogenic immunity induced via the gut-mammary gland-secretory IgA (sIgA) axis, remains the most promising and effective way to protect suckling piglets from PEDV. Therefore, a successful PEDV vaccine must induce protective maternal IgA antibodies that passively transfer into colostrum and milk. Identifying variables that influence lymphocyte migration and IgA secretion during gestation and lactation is imperative for designing maternal immunization strategies that generate the highest amount of lactogenic immune protection against PEDV in suckling piglets. Because pregnancy-associated immune alterations influence viral pathogenesis and adaptive immune responses in many different species, a better understanding of host immune responses to PEDV in pregnant swine may translate into improved maternal immunization strategies against enteric pathogens for multiple species. In this review, we discuss the role of host factors during pregnancy on antiviral immunity and their implications for generating protective lactogenic immunity in suckling neonates. Full article

(This article belongs to the Special Issue Immune Response to Porcine Epidemic Diarrhea Virus)

► Show Figures

Figure 1

12 pages, 1173 KB

Open AccessEditor’s ChoiceArticle

Metabolic Changes of Mycobacterium tuberculosis during the Anti-Tuberculosis Therapy

by Julia Bespyatykh, Egor Shitikov, Dmitry Bespiatykh, Andrei Guliaev, Ksenia Klimina, Vladimir Veselovsky, Georgij Arapidi, Marine Dogonadze, Viacheslav Zhuravlev, Elena Ilina and Vadim Govorun

Pathogens 2020, 9(2), 131; https://doi.org/10.3390/pathogens9020131 - 18 Feb 2020

Cited by 15 | Viewed by 5173

Abstract

Tuberculosis, caused by Mycobacterium tuberculosis complex bacteria, remains one of the most pressing health problems. Despite the general trend towards reduction of the disease incidence rate, the situation remains extremely tense due to the distribution of the resistant forms. Most often, these strains [...] Read more.

Tuberculosis, caused by Mycobacterium tuberculosis complex bacteria, remains one of the most pressing health problems. Despite the general trend towards reduction of the disease incidence rate, the situation remains extremely tense due to the distribution of the resistant forms. Most often, these strains emerge through the intra-host microevolution of the pathogen during treatment failure. In the present study, the focus was on three serial clinical isolates of Mycobacterium tuberculosis Beijing B0/W148 cluster from one patient with pulmonary tuberculosis, to evaluate their changes in metabolism during anti-tuberculosis therapy. Using whole genome sequencing (WGS), 9 polymorphisms were determined, which occurred in a stepwise or transient manner during treatment and were linked to the resistance (GyrA D94A; inhA t-8a) or virulence. The effect of the inhA t-8a mutation was confirmed on both proteomic and transcriptomic levels. Additionally, the amount of RpsL protein, which is a target of anti-tuberculosis drugs, was reduced. At the systemic level, profound changes in metabolism, linked to the evolution of the pathogen in the host and the effects of therapy, were documented. An overabundance of the FAS-II system proteins (HtdX, HtdY) and expression changes in the virulence factors have been observed at the RNA and protein levels. Full article

(This article belongs to the Special Issue Mycobacterium tuberculosis Pathogenesis, Infection Prevention and Treatment)

► Show Figures

Figure 1

16 pages, 4280 KB

Open AccessEditor’s ChoiceArticle

Identification of a Neisseria gonorrhoeae Histone Deacetylase: Epigenetic Impact on Host Gene Expression

by Susu M. Zughaier, Corinne E. Rouquette-Loughlin and William M. Shafer

Pathogens 2020, 9(2), 132; https://doi.org/10.3390/pathogens9020132 - 18 Feb 2020

Cited by 12 | Viewed by 4963

Abstract

Epigenetic reprogramming in macrophages is termed trained innate immunity, which regulates immune tolerance and limits tissue damage during infection. Neisseria gonorrhoeae is a strict human pathogen that causes the sexually transmitted infection termed gonorrhea. Here, we report that this pathogen harbors a gene [...] Read more.

Epigenetic reprogramming in macrophages is termed trained innate immunity, which regulates immune tolerance and limits tissue damage during infection. Neisseria gonorrhoeae is a strict human pathogen that causes the sexually transmitted infection termed gonorrhea. Here, we report that this pathogen harbors a gene that encodes a histone deacetylase-like enzyme (Gc-HDAC) that shares high 3D-homology to human HDAC1, HDAC2 and HDAC8. A Gc-HDAC null mutant was constructed to determine the biologic significance of this gene. The results showed that WT gonococci reduced the expression of host defense peptides LL-37, HBD-1 and SLPI in macrophages when compared to its Gc-HDAC-deficient isogenic strain. The enrichment of epigenetic marks in histone tails control gene expression and are known to change during bacterial infections. To investigate whether gonococci exert epigenetic modifications on host chromatin, the enrichment of acetylated lysine 9 in histone 3 (H3K9ac) was investigated using the TLR-focused ChIP array system. The data showed that infection with WT gonococci led to higher H3K9ac enrichment at the promoters of pro-inflammatory mediators’ genes, many TLRs, adaptor proteins and transcription factors, suggesting gene activation when compared to infection with the Gc-HDAC-deficient mutant. Taken together, the data suggest that gonococci can exert epigenetic modifications on host cells to modulate certain macrophage defense genes, leading to a maladaptive state of trained immunity. Full article

(This article belongs to the Special Issue Neisseria gonorrhoeae Infections)

► Show Figures

Graphical abstract

27 pages, 923 KB

Open AccessEditor’s ChoiceReview

HPV Oncoproteins and the Ubiquitin Proteasome System: A Signature of Malignancy?

by Anamaria Đukić, Lucija Lulić, Miranda Thomas, Josipa Skelin, Nathaniel Edward Bennett Saidu, Magdalena Grce, Lawrence Banks and Vjekoslav Tomaić

Pathogens 2020, 9(2), 133; https://doi.org/10.3390/pathogens9020133 - 18 Feb 2020

Cited by 39 | Viewed by 6674

Abstract

Human papillomavirus (HPV) E6 and E7 oncoproteins are critical for development and maintenance of the malignant phenotype in HPV-induced cancers. These two viral oncoproteins interfere with a plethora of cellular pathways, including the regulation of cell cycle and the control of apoptosis, which [...] Read more.

Human papillomavirus (HPV) E6 and E7 oncoproteins are critical for development and maintenance of the malignant phenotype in HPV-induced cancers. These two viral oncoproteins interfere with a plethora of cellular pathways, including the regulation of cell cycle and the control of apoptosis, which are critical in maintaining normal cellular functions. E6 and E7 bind directly with certain components of the Ubiquitin Proteasome System (UPS), enabling them to manipulate a number of important cellular pathways. These activities are the means by which HPV establishes an environment supporting the normal viral life cycle, however in some instances they can also lead to the development of malignancy. In this review, we have discussed how E6 and E7 oncoproteins from alpha and beta HPV types interact with the components of the UPS, and how this interplay contributes to the development of cancer. Full article

(This article belongs to the Special Issue Viral-host interactions and determinants of human papillomavirus (HPV) life cycle and pathogenesis)

► Show Figures

Figure 1

19 pages, 2011 KB

Open AccessEditor’s ChoiceArticle

Ecology and Infection Dynamics of Multi-Host Amdoparvoviral and Protoparvoviral Carnivore Pathogens

by Marta Canuti, Melissa Todd, Paige Monteiro, Kalia Van Osch, Richard Weir, Helen Schwantje, Ann P. Britton and Andrew S. Lang

Pathogens 2020, 9(2), 124; https://doi.org/10.3390/pathogens9020124 - 15 Feb 2020

Cited by 32 | Viewed by 4687

Abstract

Amdoparvovirus and Protoparvovirus are monophyletic viral genera that infect carnivores. We performed surveillance for and sequence analyses of parvoviruses in mustelids in insular British Columbia to investigate parvoviral maintenance and cross-species transmission among wildlife. Overall, 19.1% (49/256) of the tested animals were parvovirus-positive. [...] Read more.

Amdoparvovirus and Protoparvovirus are monophyletic viral genera that infect carnivores. We performed surveillance for and sequence analyses of parvoviruses in mustelids in insular British Columbia to investigate parvoviral maintenance and cross-species transmission among wildlife. Overall, 19.1% (49/256) of the tested animals were parvovirus-positive. Aleutian mink disease virus (AMDV) was more prevalent in mink (41.6%, 32/77) than martens (3.1%, 4/130), feline panleukopenia virus (FPV) was more prevalent in otters (27.3%, 6/22) than mink (5.2%, 4/77) or martens (2.3%, 3/130), and canine parvovirus 2 (CPV-2) was found in one mink, one otter, and zero ermines (N = 27). Viruses were endemic and bottleneck events, founder effects, and genetic drift generated regional lineages. We identified two local closely related AMDV lineages, one CPV-2 lineage, and five FPV lineages. Highly similar viruses were identified in different hosts, demonstrating cross-species transmission. The likelihood for cross-species transmission differed among viruses and some species likely represented dead-end spillover hosts. We suggest that there are principal maintenance hosts (otters for FPV, raccoons for CPV-2/FPV, mink for AMDV) that enable viral persistence and serve as sources for other susceptible species. In this multi-host system, viral and host factors affect viral persistence and distribution, shaping parvoviral ecology and evolution, with implications for insular carnivore conservation. Full article

(This article belongs to the Special Issue Modeling Virus Dynamics and Evolution)

► Show Figures

Figure 1

19 pages, 2467 KB

Open AccessEditor’s ChoiceArticle

Enterovirus 71 Infection Shapes Host T Cell Receptor Repertoire and Presumably Expands VP1-Specific TCRβ CDR3 Cluster

by Yu-Wen Liao, Bing-Ching Ho, Min-Hsuan Chen and Sung-Liang Yu

Pathogens 2020, 9(2), 121; https://doi.org/10.3390/pathogens9020121 - 14 Feb 2020

Cited by 3 | Viewed by 3343

Abstract

Enterovirus 71 (EV71) has become an important public health problem in the Asia-Pacific region in the past decades. EV71 infection might cause neurological and psychiatric complications and even death. Although an EV71 vaccine has been currently approved, there is no effective therapy for [...] Read more.

Enterovirus 71 (EV71) has become an important public health problem in the Asia-Pacific region in the past decades. EV71 infection might cause neurological and psychiatric complications and even death. Although an EV71 vaccine has been currently approved, there is no effective therapy for treating EV71-infected patients. Virus infections have been reported to shape host T cell receptor (TCR) repertoire. Therefore, understanding of host TCR repertoire in EV71 infection could better the knowledge in viral pathogenesis and further benefit the anti-viral therapy development. In this study, we used a mouse-adapted EV71 (mEV71) model to observe changes of host TCR repertoire in an EV71-infected central nervous system. Neonate mice were infected with mEV71 and mouse brainstem TCRβ repertoires were explored. Here, we reported that mEV71 infection impacted host brainstem TCRβ repertoire, where mEV71 infection skewed TCRβ diversity, changed VJ combination usages, and further expanded specific TCRβ CDR3 clones. Using bioinformatics analysis and ligand-binding prediction, we speculated the expanded TCRβ CDR3 clone harboring CASSLGANSDYTF sequence was capable of binding cleaved EV71 VP1 peptides in concert with major histocompatibility complex (MHC) molecules. We observed that mEV71 infection shaped host TCRβ repertoire and presumably expanded VP1-specific TCRβ CDR3 in mEV71-infected mouse brainstem that integrated EV71 pathogenesis in central nervous system. Full article

(This article belongs to the Section Human Pathogens)

► Show Figures

Figure 1

14 pages, 2831 KB

Open AccessEditor’s ChoiceArticle

ZnO Nanoflower-Based NanoPCR as an Efficient Diagnostic Tool for Quick Diagnosis of Canine Vector-Borne Pathogens

by Archana Upadhyay, Huan Yang, Bilal Zaman, Lei Zhang, Yundi Wu, Jinhua Wang, Jianguo Zhao, Chenghong Liao and Qian Han

Pathogens 2020, 9(2), 122; https://doi.org/10.3390/pathogens9020122 - 14 Feb 2020

Cited by 19 | Viewed by 4411

Abstract

Polymerase chain reaction (PCR) is a unique technique in molecular biology and biotechnology for amplifying target DNA strands, and is also considered as a gold standard for the diagnosis of many canine diseases as well as many other infectious diseases. However, PCR still [...] Read more.

Polymerase chain reaction (PCR) is a unique technique in molecular biology and biotechnology for amplifying target DNA strands, and is also considered as a gold standard for the diagnosis of many canine diseases as well as many other infectious diseases. However, PCR still faces many challenges and issues related to its sensitivity, specificity, efficiency, and turnaround time. To address these issues, we described the use of unique ZnO nanoflowers in PCR reaction and an efficient ZnO nanoflower-based PCR (nanoPCR) for the molecular diagnosis of canine vector-borne diseases (CVBDs). A total of 1 mM of an aqueous solution of ZnO nanoflowers incorporated in PCR showed a significant enhancement of the PCR assay with respect to its sensitivity and specificity for the diagnosis of two important CVBDs, Babesia canis vogeli and Hepatozoon canis. Interestingly, it drastically reduced the turnaround time of the PCR assay without compromising the yield of the amplified DNA, which can be of benefit for veterinary practitioners for the improved management of diseases. This can be attributed to the favorable adsorption of ZnO nanoflowers to the DNA and thermal conductivity of ZnO nanoflowers. The unique ZnO nanoflower-assisted nanoPCR greatly improved the yield, purity, and quality of the amplified products, but the mechanism behind these properties and the effects and changes due to the different concentrations of ZnO nanoflowers in the PCR system needs to be further studied. Full article

(This article belongs to the Special Issue Canine and Feline Infectious Diseases)

► Show Figures

Figure 1

16 pages, 2531 KB

Open AccessEditor’s ChoiceArticle

Dynamic Network of Interactions in the Wildlife-Livestock Interface in Mediterranean Spain: An Epidemiological Point of View

by Roxana Triguero-Ocaña, Beatriz Martínez-López, Joaquín Vicente, José A. Barasona, Jordi Martínez-Guijosa and Pelayo Acevedo

Pathogens 2020, 9(2), 120; https://doi.org/10.3390/pathogens9020120 - 13 Feb 2020

Cited by 36 | Viewed by 5029

Abstract

The correct management of diseases that are transmitted between wildlife and livestock requires a reliable estimate of the pathogen transmission rate. The calculation of this parameter is a challenge for epidemiologists, since transmission can occur through multiple pathways. The social network analysis is [...] Read more.

The correct management of diseases that are transmitted between wildlife and livestock requires a reliable estimate of the pathogen transmission rate. The calculation of this parameter is a challenge for epidemiologists, since transmission can occur through multiple pathways. The social network analysis is a widely used tool in epidemiology due to its capacity to identify individuals and communities with relevant roles for pathogen transmission. In the present work, we studied the dynamic network of interactions in a complex epidemiological scenario using information from different methodologies. In 2015, nine red deer, seven fallow deer, six wild boar and nine cattle were simultaneously monitored using GPS-GSM-Proximity collars in Doñana National Park. In addition, 16 proximity loggers were set in aggregation points. Using the social network analysis, we studied the dynamic network of interactions, including direct and indirect interactions, between individuals of different species and the potential transmission of pathogens within this network. The results show a high connection between species through indirect interactions, with a marked seasonality in the conformation of new interactions. Within the network, we differentiated four communities that included individuals of all the species. Regarding the transmission of pathogens, we observed the important role that fallow deer could be playing in the maintenance and transmission of pathogens to livestock. The present work shows the need to consider different types of methodologies in order to understand the complete functioning of the network of interactions at the wildlife/livestock interface. It also provides a methodological approach applicable to the management of shared diseases. Full article

(This article belongs to the Special Issue Tuberculosis Epidemiology and Control in Multi-Host Systems)

► Show Figures

Figure 1

13 pages, 740 KB

Open AccessEditor’s ChoiceArticle

High Prevalence of Strongyloidiasis in Spain: A Hospital-Based Study

by Ana Requena-Méndez, Joaquin Salas-Coronas, Fernando Salvador, Joan Gomez-Junyent, Judith Villar-Garcia, Miguel Santin, Carme Muñoz, Ana González-Cordón, Maria Teresa Cabezas Fernández, Elena Sulleiro, Maria del Mar Arenas, Dolors Somoza, Jose Vazquez-Villegas, Begoña Treviño, Esperanza Rodríguez, Maria Eugenia Valls, Jaume LLaberia-Marcual, Carme Subirá and Jose Muñoz

Pathogens 2020, 9(2), 107; https://doi.org/10.3390/pathogens9020107 - 11 Feb 2020

Cited by 11 | Viewed by 4927

Abstract

Introduction: Strongyloidiasis is a prevailing helminth infection ubiquitous in tropical and subtropical areas, however, seroprevalence data are scarce in migrant populations, particularly for those coming for Asia. Methods: This study aims at evaluating the prevalence of S. stercoralis at the hospital [...] Read more.

Introduction: Strongyloidiasis is a prevailing helminth infection ubiquitous in tropical and subtropical areas, however, seroprevalence data are scarce in migrant populations, particularly for those coming for Asia. Methods: This study aims at evaluating the prevalence of S. stercoralis at the hospital level in migrant populations or long term travellers being attended in out-patient and in-patient units as part of a systematic screening implemented in six Spanish hospitals. A cross-sectional study was conducted and systematic screening for S. stercoralis infection using serological tests was offered to all eligible participants. Results: The overall seroprevalence of S. stercoralis was 9.04% (95%CI 7.76–10.31). The seroprevalence of people with a risk of infection acquired in Africa and Latin America was 9.35% (95%CI 7.01–11.69), 9.22% (7.5–10.93), respectively. The number of individuals coming from Asian countries was significantly smaller and the overall prevalence in these countries was 2.9% (95%CI −0.3–6.2). The seroprevalence in units attending potentially immunosuppressed patients was significantly lower (5.64%) compared with other units of the hospital (10.20%) or Tropical diseases units (13.33%) (p < 0.001). Conclusions: We report a hospital-based strongyloidiasis seroprevalence of almost 10% in a mobile population coming from endemic areas suggesting the need of implementing strongyloidiasis screening in hospitalized patients coming from endemic areas, particularly if they are at risk of immunosuppression. Full article

(This article belongs to the Special Issue Prevalence of Strongyloidiasis and Schistosomiasis)

► Show Figures

Figure 1

46 pages, 1423 KB

Open AccessEditor’s ChoiceReview

Betanodavirus and VER Disease: A 30-year Research Review

by Isabel Bandín and Sandra Souto

Pathogens 2020, 9(2), 106; https://doi.org/10.3390/pathogens9020106 - 9 Feb 2020

Cited by 241 | Viewed by 20071

Abstract

The outbreaks of viral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), represent one of the main infectious threats for marine aquaculture worldwide. Since the first description of the disease at the end of the 1980s, a considerable amount of research [...] Read more.

The outbreaks of viral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), represent one of the main infectious threats for marine aquaculture worldwide. Since the first description of the disease at the end of the 1980s, a considerable amount of research has gone into understanding the mechanisms involved in fish infection, developing reliable diagnostic methods, and control measures, and several comprehensive reviews have been published to date. This review focuses on host–virus interaction and epidemiological aspects, comprising viral distribution and transmission as well as the continuously increasing host range (177 susceptible marine species and epizootic outbreaks reported in 62 of them), with special emphasis on genotypes and the effect of global warming on NNV infection, but also including the latest findings in the NNV life cycle and virulence as well as diagnostic methods and VER disease control. Full article

(This article belongs to the Special Issue Viral Diseases of Fish)

► Show Figures

Figure 1

17 pages, 2205 KB

Open AccessEditor’s ChoiceReview

Epstein–Barr Virus and Helicobacter Pylori Co-Infection in Non-Malignant Gastroduodenal Disorders

by Ramsés Dávila-Collado, Oscar Jarquín-Durán, Le Thanh Dong and J. Luis Espinoza

Pathogens 2020, 9(2), 104; https://doi.org/10.3390/pathogens9020104 - 6 Feb 2020

Cited by 37 | Viewed by 7355

Abstract

Epstein–Barr virus (EBV) and Helicobacter pylori (H. pylori) are two pathogens associated with the development of various human cancers. The coexistence of both microorganisms in gastric cancer specimens has been increasingly reported, suggesting that crosstalk of both pathogens may be implicated [...] Read more.

Epstein–Barr virus (EBV) and Helicobacter pylori (H. pylori) are two pathogens associated with the development of various human cancers. The coexistence of both microorganisms in gastric cancer specimens has been increasingly reported, suggesting that crosstalk of both pathogens may be implicated in the carcinogenesis process. Considering that chronic inflammation is an initial step in the development of several cancers, including gastric cancer, we conducted a systematic review to comprehensively evaluate publications in which EBV and H. pylori co-infection has been documented in patients with non-malignant gastroduodenal disorders (NMGDs), including gastritis, peptic ulcer disease (PUD), and dyspepsia. We searched the PubMed database up to August 2019, as well as publication references and, among the nine studies that met the inclusion criteria, we identified six studies assessing EBV infection directly in gastric tissues (total 949 patients) and three studies in which EBV infection status was determined by serological methods (total 662 patients). Due to the substantial methodological and clinical heterogeneity among studies identified, we could not conduct a meta-analysis. The overall prevalence of EBV + H. pylori co-infection in NMGDs was 34% (range 1.8% to 60%). A higher co-infection rate (EBV + H. pylori) was reported in studies in which EBV was documented by serological methods in comparison with studies in which EBV infection was directly assessed in gastric specimens. The majority of these studies were conducted in Latin-America and India, with most of them comparing NMGDs with gastric cancer, but there were no studies comparing the co-infection rate in NMGDs with that in asymptomatic individuals. In comparison with gastritis caused by only one of these pathogens, EBV + H. pylori co-infection was associated with increased severity of gastric inflammation. In conclusion, only relatively small studies testing EBV and H. pylori co-infection in NMGDs have been published to date and the variable report results are likely influenced by geographic factors and detection methods. Full article

(This article belongs to the Section Human Pathogens)

► Show Figures

Figure 1

24 pages, 4550 KB

Open AccessEditor’s ChoiceArticle

Comparison of the Transcriptome Response within the Swine Tracheobronchial Lymphnode Following Infection with PRRSV, PCV-2 or IAV-S.

by Laura C. Miller, Damarius S. Fleming and Kelly M. Lager

Pathogens 2020, 9(2), 99; https://doi.org/10.3390/pathogens9020099 - 5 Feb 2020

Cited by 7 | Viewed by 4120

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major respiratory pathogen of swine that has become extremely costly to the swine industry worldwide, often causing losses in production and animal life due to their ease of spread. However, the intracellular changes that [...] Read more.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major respiratory pathogen of swine that has become extremely costly to the swine industry worldwide, often causing losses in production and animal life due to their ease of spread. However, the intracellular changes that occur in pigs following viral respiratory infections are still scantily understood for PRRSV, as well as other viral respiratory infections. The aim of this study was to acquire a better understanding of the PRRS disease by comparing gene expression changes that occur in tracheobronchial lymph nodes (TBLN) of pigs infected with either porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV-2), or swine influenza A virus (IAV-S) infections. The study identified and compared gene expression changes in the TBLN of 80 pigs following infection by PRRSV, PCV-2, IAV-S, or sham inoculation. Total RNA was pooled for each group and time-point (1, 3, 6, and 14 dpi) to make 16 libraries—analyses are by Digital Gene Expression Tag Profiling (DGETP). The data underwent standard filtering to generate a list of sequence tag raw counts that were then analyzed using multidimensional and differential expression statistical tests. The results showed that PRRSV, IAV-S and PCV-2 viral infections followed a clinical course in the pigs typical of experimental infection of young pigs with these viruses. Gene expression results echoed this course, as well as uncovered genes related to intersecting and unique host immune responses to the three viruses. By testing and observing the host response to other respiratory viruses, our study has elucidated similarities and differences that can assist in the development of vaccines and therapeutics that shorten or prevent a chronic PRRSV infection. Full article

(This article belongs to the Section Animal Pathogens)

► Show Figures

Figure 1

13 pages, 300 KB

Open AccessEditor’s ChoiceArticle

Molecular Detection of Antimalarial Drug Resistance in Plasmodium vivax from Returned Travellers to NSW, Australia during 2008–2018

by Chaturong Noisang, Wieland Meyer, Nongyao Sawangjaroen, John Ellis and Rogan Lee

Pathogens 2020, 9(2), 101; https://doi.org/10.3390/pathogens9020101 - 5 Feb 2020

Cited by 8 | Viewed by 4318

Abstract

To monitor drug resistance in Plasmodium vivax, a multidrug resistance 1 (Pvmdr1) gene and a putative transporter protein (Pvcrt-o) gene were used as molecular markers for chloroquine resistance. The biomarkers, the dihydrofolate reductase (Pvdhfr) gene and [...] Read more.

To monitor drug resistance in Plasmodium vivax, a multidrug resistance 1 (Pvmdr1) gene and a putative transporter protein (Pvcrt-o) gene were used as molecular markers for chloroquine resistance. The biomarkers, the dihydrofolate reductase (Pvdhfr) gene and the dihydropteroate synthetase (Pvdhps) gene, were also used for the detection of resistance to sulphadoxine-pyrimethamine (SP); this drug is often accidentally used to treat P. vivax infections. Clinical blood samples (n = 120) were collected from patients who had been to one of eight malaria-endemic countries and diagnosed with P. vivax infection. The chloroquine resistance marker, the Pvmdr1 gene, showed F976:L1076 mutations and L1076 mutation. A K10 insertion in the Pvcrt-o gene was also found among the samples successfully sequenced. A combination of L/I57:R58:M61:T117 mutations in the Pvdhfr gene and G383:G553 mutations in the Pvdhps gene were also observed. Mutations found in these genes indicate that drug resistance is present in these eight countries. Whether or not countries are using chloroquine to treat P. vivax, there appears to be an increase in mutation numbers in resistance gene markers. The detected changes in mutation rates of these genes do suggest that there is still a trend towards increasing P. vivax resistance to chloroquine. The presence of the mutations associated with SP resistance indicates that P. vivax has had exposure to SP and this may be a consequence of either misdiagnosis or coinfections with P. falciparum in the past. Full article

(This article belongs to the Special Issue Addressing Plasmodium vivax: From Control to Elimination)

25 pages, 1593 KB

Open AccessEditor’s ChoiceReview

The Infectious Pancreatic Necrosis Virus (IPNV) and its Virulence Determinants: What is Known and What Should be Known

by Carlos P. Dopazo

Pathogens 2020, 9(2), 94; https://doi.org/10.3390/pathogens9020094 - 4 Feb 2020

Cited by 68 | Viewed by 10298

Abstract

Infectious pancreatic necrosis (IPN) is a disease of great concern in aquaculture, mainly among salmonid farmers, since losses in salmonid fish—mostly very young rainbow trout (Salmo gairdnery) fry and Atlantic salmon (Salmo salar) post-smolt—frequently reach 80–90% of stocks. The [...] Read more.

Infectious pancreatic necrosis (IPN) is a disease of great concern in aquaculture, mainly among salmonid farmers, since losses in salmonid fish—mostly very young rainbow trout (Salmo gairdnery) fry and Atlantic salmon (Salmo salar) post-smolt—frequently reach 80–90% of stocks. The virus causing the typical signs of the IPN disease in salmonids, named infectious pancreatic necrosis virus (IPNV), has also been isolated from other fish species either suffering related diseases (then named IPNV-like virus) or asymptomatic; the general term aquabirnavirus is used to encompass all these viruses. Aquabirnaviruses are non-enveloped, icosahedral bisegmented dsRNA viruses, whose genome codifies five viral proteins, three of which are structural, and one of them is an RNA-dependent RNA polymerase. Due to the great importance of the disease, there have been great efforts to find a way to predict the level of virulence of IPNV isolates. The viral genome and proteins have been the main focus of research. However, to date such a reliable magic marker has not been discovered. This review describes the processes followed for decades in the attempts to discover the viral determinants of virulence, and to help the reader understand how viral components can be involved in virulence modulation in vitro and in vivo. There is also a brief description of the disease, of host defenses, and of the molecular structure and function of the virus and its viral components. Full article

(This article belongs to the Special Issue Viral Diseases of Fish)

► Show Figures

Figure 1

16 pages, 3645 KB

Open AccessEditor’s ChoiceArticle

Map3k14 as a Regulator of Innate and Adaptive Immune Response during Acute Viral Infection

by Thamer A. Hamdan, Hilal Bhat, Lamin B. Cham, Tom Adomati, Judith Lang, Fanghui Li, Ali Murtaza, Cornelia Hardt, Philipp A. Lang, Vikas Duhan and Karl S. Lang

Pathogens 2020, 9(2), 96; https://doi.org/10.3390/pathogens9020096 - 4 Feb 2020

Cited by 8 | Viewed by 4296

Abstract

The replication of virus in secondary lymphoid organs is crucial for the activation of antigen-presenting cells. Balanced viral replication ensures the sufficient availability of antigens and production of cytokines, and both of which are needed for virus-specific immune activation and viral elimination. Host [...] Read more.

The replication of virus in secondary lymphoid organs is crucial for the activation of antigen-presenting cells. Balanced viral replication ensures the sufficient availability of antigens and production of cytokines, and both of which are needed for virus-specific immune activation and viral elimination. Host factors that regulate coordinated viral replication are not fully understood. In the study reported here, we identified Map3k14 as an important regulator of enforced viral replication in the spleen while performing genome-wide association studies of various inbred mouse lines in a model of lymphocytic choriomeningitis virus (LCMV) infection. When alymphoplasia mice (aly/aly, Map3k14^aly/aly, or Nik^aly/aly), which carry a mutation in Map3k14, were infected with LCMV or vesicular stomatitis virus (VSV), they display early reductions in early viral replication in the spleen, reduced innate and adaptive immune activation, and lack of viral control. Histologically, scant B cells and the lack of CD169⁺ macrophages correlated with reduced immune activation in Map3k14^aly/aly mice. The transfer of wildtype B cells into Map3k14^aly/aly mice repopulated CD169⁺ macrophages, restored enforced viral replication, and resulted in enhanced immune activation and faster viral control. Full article

(This article belongs to the Section Immunological Responses and Immune Defense Mechanisms)

► Show Figures

Figure 1

13 pages, 2789 KB

Open AccessEditor’s ChoiceArticle

Isolation of Naegleria spp. from a Brazilian Water Source

by Natália Karla Bellini, Ana Letícia Moreira da Fonseca, María Reyes-Batlle, Jacob Lorenzo-Morales, Odete Rocha and Otavio Henrique Thiemann

Pathogens 2020, 9(2), 90; https://doi.org/10.3390/pathogens9020090 - 31 Jan 2020

Cited by 23 | Viewed by 5817

Abstract

The genus Naegleria, of the free-living amoeba (FLA) group, has been investigated mainly due to its human health impact, resulting in deadly infections and their worldwide distribution on freshwater systems. Naegleria fowleri, colloquially known as the “brain-eating amoeba,” is the most [...] Read more.

The genus Naegleria, of the free-living amoeba (FLA) group, has been investigated mainly due to its human health impact, resulting in deadly infections and their worldwide distribution on freshwater systems. Naegleria fowleri, colloquially known as the “brain-eating amoeba,” is the most studied Naegleria species because it causes primary amoebic meningoencephalitis (PAM) of high lethality. The assessment of FLA biodiversity is fundamental to evaluate the presence of pathogenic species and the possibility of human contamination. However, the knowledge of FLA distribution in Brazil is unknown, and to rectify this situation, we present research on identifying Naegleria spp. in the Monjolinho River as a model study. The river is a public Brazilian freshwater source that crosses the city of São Carlos, in São Paulo state, Brazil. Five distinct sampling sites were examined through limnological features, trophozoites culturing, and PCR against internal transcribed spacer (ITS) regions and 5.8S rRNA sequences. The results identified N. philippinensis, N. canariensisi, N. australiensis, N. gruberi, N. dobsoni sequences, as well as a Hartmannella sequence. The methodology delineated here represents the first Brazilian Naegleria spp. study on a freshwater system. Our results stress the urgency of a large scale evaluation of the presence of free-living amoebas in Brazil. Full article

(This article belongs to the Special Issue Emerging Parasitic Protozoa)

► Show Figures

Graphical abstract

19 pages, 1494 KB

Open AccessEditor’s ChoiceReview

The Laboratory Diagnosis of Neisseria gonorrhoeae: Current Testing and Future Demands

by Thomas Meyer and Susanne Buder

Pathogens 2020, 9(2), 91; https://doi.org/10.3390/pathogens9020091 - 31 Jan 2020

Cited by 72 | Viewed by 26968

Abstract

The ideal laboratory test to detect Neisseria gonorrhoeae (Ng) should be sensitive, specific, easy to use, rapid, and affordable and should provide information about susceptibility to antimicrobial drugs. Currently, such a test is not available and presumably will not be in [...] Read more.

The ideal laboratory test to detect Neisseria gonorrhoeae (Ng) should be sensitive, specific, easy to use, rapid, and affordable and should provide information about susceptibility to antimicrobial drugs. Currently, such a test is not available and presumably will not be in the near future. Thus, diagnosis of gonococcal infections presently includes application of different techniques to address these requirements. Microscopy may produce rapid results but lacks sensitivity in many cases (except symptomatic urogenital infections in males). Highest sensitivity to detect Ng was shown for nucleic acid amplification technologies (NAATs), which, however, are less specific than culture. In addition, comprehensive analysis of antibiotic resistance is accomplished only by in vitro antimicrobial susceptibility testing of cultured isolates. As a light at the end of the tunnel, new developments of molecular techniques and microfluidic systems represent promising opportunities to design point-of-care tests for rapid detection of Ng with high sensitivity and specificity, and there is reason to hope that such tests may also provide antimicrobial resistance data in the future. Full article

(This article belongs to the Special Issue Neisseria gonorrhoeae Infections)

► Show Figures

Graphical abstract

18 pages, 2264 KB

Open AccessEditor’s ChoiceArticle

Increasing the Safety Profile of the Master Donor Live Attenuated Influenza Vaccine

by Thomas A. Hilimire, Aitor Nogales, Kevin Chiem, Javier Ortego and Luis Martinez-Sobrido

Pathogens 2020, 9(2), 86; https://doi.org/10.3390/pathogens9020086 - 29 Jan 2020

Cited by 16 | Viewed by 3284

Abstract

Seasonal influenza epidemics remain one of the largest public health burdens nowadays. The best and most effective strategy to date in preventing influenza infection is a worldwide vaccination campaign. Currently, two vaccines are available to the public for the treatment of influenza infection, [...] Read more.

Seasonal influenza epidemics remain one of the largest public health burdens nowadays. The best and most effective strategy to date in preventing influenza infection is a worldwide vaccination campaign. Currently, two vaccines are available to the public for the treatment of influenza infection, the chemically Inactivated Influenza Vaccine (IIV) and the Live Attenuated Influenza Vaccine (LAIV). However, the LAIV is not recommended for parts of the population, such as children under the age of two, immunocompromised individuals, the elderly, and pregnant adults. In order to improve the safety of the LAIV and make it available to more of the population, we sought to further attenuate the LAIV. In this study, we demonstrate that the influenza A virus (IAV) master donor virus (MDV) A/Ann Arbor/6/60 H2N2 LAIV can inhibit host gene expression using both the PA-X and NS1 proteins. Furthermore, we show that by removing PA-X, we can limit the replication of the MDV LAIV in a mouse model, while maintaining full protective efficacy. This work demonstrates a broadly applicable strategy of tuning the amount of host antiviral responses induced by the IAV MDV for the development of newer and safer LAIVs. Moreover, our results also demonstrate, for the first time, the feasibility of genetically manipulating the backbone of the IAV MDV to improve the efficacy of the current IAV LAIV. Full article

(This article belongs to the Special Issue Influenza Virus and Vaccination)

► Show Figures

Figure 1

12 pages, 680 KB

Open AccessEditor’s ChoiceReview

The Circadian Clock, the Immune System, and Viral Infections: The Intricate Relationship Between Biological Time and Host-Virus Interaction

by Gianluigi Mazzoccoli, Manlio Vinciguerra, Annalucia Carbone and Angela Relógio

Pathogens 2020, 9(2), 83; https://doi.org/10.3390/pathogens9020083 - 27 Jan 2020

Cited by 52 | Viewed by 9675

Abstract

Living beings spend their lives and carry out their daily activities interacting with environmental situations that present space-time variations and that involve contact with other life forms, which may behave as commensals or as invaders and/or parasites. The characteristics of the environment, as [...] Read more.

Living beings spend their lives and carry out their daily activities interacting with environmental situations that present space-time variations and that involve contact with other life forms, which may behave as commensals or as invaders and/or parasites. The characteristics of the environment, as well as the processes that support the maintenance of life and that characterize the execution of activities of daily life generally present periodic variations, which are mostly synchronized with the light–dark cycle determined by Earth’s rotation on its axis. These rhythms with 24-h periodicity, defined as circadian, influence events linked to the interaction between hosts and hosted microorganisms and can dramatically determine the outcome of this interplay. As for the various pathological conditions resulting from host–microorganism interactions, a particularly interesting scenario concerns infections by viruses. When a viral agent enters the body, it alters the biological processes of the infected cells in order to favour its replication and to spread to various tissues. Though our knowledge concerning the mutual influence between the biological clock and viruses is still limited, recent studies start to unravel interesting aspects of the clock–virus molecular interplay. Three different aspects of this interplay are addressed in this mini-review and include the circadian regulation of both innate and adaptive immune systems, the impact of the biological clock on viral infection itself, and finally the putative perturbations that the virus may confer to the clock leading to its deregulation. Full article

► Show Figures

Figure 1

12 pages, 1584 KB

Open AccessEditor’s ChoiceArticle

Suicidal Leishmania

by Lucie Podešvová, Tereza Leštinová, Eva Horáková, Julius Lukeš, Petr Volf and Vyacheslav Yurchenko

Pathogens 2020, 9(2), 79; https://doi.org/10.3390/pathogens9020079 - 25 Jan 2020

Cited by 9 | Viewed by 3573

Abstract

Leishmania are obligate intracellular parasites known to have developed successful ways of efficient immunity evasion. Because of this, leishmaniasis, a disease caused by these flagellated protists, is ranked as one of the most serious tropical infections worldwide. Neither prophylactic medication, nor vaccination has [...] Read more.

Leishmania are obligate intracellular parasites known to have developed successful ways of efficient immunity evasion. Because of this, leishmaniasis, a disease caused by these flagellated protists, is ranked as one of the most serious tropical infections worldwide. Neither prophylactic medication, nor vaccination has been developed thus far, even though the infection has usually led to strong and long-lasting immunity. In this paper, we describe a “suicidal” system established in Leishmania mexicana, a human pathogen causing cutaneous leishmaniasis. This system is based on the expression and (de)stabilization of a basic phospholipase A2 toxin from the Bothrops pauloensis snake venom, which leads to the inducible cell death of the parasites in vitro. Furthermore, the suicidal strain was highly attenuated during macrophage infection, regardless of the toxin stabilization. Such a deliberately weakened parasite could be used to vaccinate the host, as its viability is regulated by the toxin stabilization, causing a profoundly reduced pathogenesis. Full article

► Show Figures

Figure 1

10 pages, 507 KB

Open AccessEditor’s ChoiceArticle

Hypermutation as an Evolutionary Mechanism for Achromobacter xylosoxidans in Cystic Fibrosis Lung Infection

by Laura Veschetti, Angela Sandri, Helle Krogh Johansen, Maria M. Lleò and Giovanni Malerba

Pathogens 2020, 9(2), 72; https://doi.org/10.3390/pathogens9020072 - 21 Jan 2020

Cited by 23 | Viewed by 3583

Abstract

Achromobacter xylosoxidans can cause chronic infections in the lungs of patients with cystic fibrosis (CF) by adapting to the specific environment. The study of longitudinal isolates allows to investigate its within-host evolution to unravel the adaptive mechanisms contributing to successful colonization. In this [...] Read more.

Achromobacter xylosoxidans can cause chronic infections in the lungs of patients with cystic fibrosis (CF) by adapting to the specific environment. The study of longitudinal isolates allows to investigate its within-host evolution to unravel the adaptive mechanisms contributing to successful colonization. In this study, four clinical isolates longitudinally collected from two chronically infected patients underwent whole genome sequencing, de novo assembly and sequence analysis. Phenotypic assays were also performed. The isolates coming from one of the patients (patient A) presented a greater number of genetic variants, diverse integrative and conjugative elements, and different protease secretion. In the first of these isolates (strain A1), we also found a large deletion in the mutS gene, involved in DNA mismatch repair (MMR). In contrast, isolates from patient B showed a lower number of variants, only one integrative and mobilizable element, no phenotypic changes, and no mutations in the MMR system. These results suggest that in the two patients the establishment of a chronic infection was mediated by different adaptive mechanisms. While the strains isolated from patient B showed a longitudinal microevolution, strain A1 can be clearly classified as a hypermutator, confirming the occurrence and importance of this adaptive mechanism in A. xylosoxidans infection. Full article

(This article belongs to the Section Human Pathogens)

► Show Figures

Figure 1

23 pages, 4526 KB

Open AccessEditor’s ChoiceArticle

Aggregatibacter actinomycetemcomitans LtxA Hijacks Endocytic Trafficking Pathways in Human Lymphocytes

by Edward T Lally, Kathleen Boesze-Battaglia, Anuradha Dhingra, Nestor M Gomez, Jinery Lora, Claire H Mitchell, Alexander Giannakakis, Syed A Fahim, Roland Benz and Nataliya Balashova

Pathogens 2020, 9(2), 74; https://doi.org/10.3390/pathogens9020074 - 21 Jan 2020

Cited by 7 | Viewed by 5480

Abstract

Leukotoxin (LtxA), from oral pathogen Aggregatibacter actinomycetemcomitans, is a secreted membrane-damaging protein. LtxA is internalized by β2 integrin LFA-1 (CD11a/CD18)-expressing leukocytes and ultimately causes cell death; however, toxin localization in the host cell is poorly understood and these studies fill this void. [...] Read more.

Leukotoxin (LtxA), from oral pathogen Aggregatibacter actinomycetemcomitans, is a secreted membrane-damaging protein. LtxA is internalized by β2 integrin LFA-1 (CD11a/CD18)-expressing leukocytes and ultimately causes cell death; however, toxin localization in the host cell is poorly understood and these studies fill this void. We investigated LtxA trafficking using multi-fluor confocal imaging, flow cytometry and Rab5a knockdown in human T lymphocyte Jurkat cells. Planar lipid bilayers were used to characterize LtxA pore-forming activity at different pHs. Our results demonstrate that the LtxA/LFA-1 complex gains access to the cytosol of Jurkat cells without evidence of plasma membrane damage, utilizing dynamin-dependent and presumably clathrin-independent mechanisms. Upon internalization, LtxA follows the LFA-1 endocytic trafficking pathways, as identified by co-localization experiments with endosomal and lysosomal markers (Rab5, Rab11A, Rab7, and Lamp1) and CD11a. Knockdown of Rab5a resulted in the loss of susceptibility of Jurkat cells to LtxA cytotoxicity, suggesting that late events of LtxA endocytic trafficking are required for toxicity. Toxin trafficking via the degradative endocytic pathway may culminate in the delivery of the protein to lysosomes or its accumulation in Rab11A-dependent recycling endosomes. The ability of LtxA to form pores at acidic pH may result in permeabilization of the endosomal and lysosomal membranes. Full article

(This article belongs to the Special Issue Aggregatibacter actinomycetemcomitans—Gram-Negative Bacterial Pathogen)

► Show Figures

Figure 1

12 pages, 3579 KB

Open AccessEditor’s ChoiceArticle

In Vivo Antiviral Effects of U18666A Against Type I Feline Infectious Peritonitis Virus

by Tomoyoshi Doki, Tomoyo Tarusawa, Tsutomu Hohdatsu and Tomomi Takano

Pathogens 2020, 9(1), 67; https://doi.org/10.3390/pathogens9010067 - 18 Jan 2020

Cited by 18 | Viewed by 5817

Abstract

Background: The cationic amphiphilic drug U18666A inhibits the proliferation of type I FIPV in vitro. In this study, we evaluated the in vivo antiviral effects of U18666A by administering it to SPF cats challenged with type I FIPV. Methods: Ten SPF cats were [...] Read more.

Background: The cationic amphiphilic drug U18666A inhibits the proliferation of type I FIPV in vitro. In this study, we evaluated the in vivo antiviral effects of U18666A by administering it to SPF cats challenged with type I FIPV. Methods: Ten SPF cats were randomly assigned to two experimental groups. FIPV KU-2 were inoculated intraperitoneally to cats. The control group was administered PBS, and the U18666A-treated group was administered U18666A subcutaneously at 2.5 mg/kg on day 0, and 1.25 mg/kg on days 2 and 4 after viral inoculation. Results: Two of the five control cats administered PBS alone developed FIP. Four of the five cats administered U18666A developed no signs of FIP. One cat that temporarily developed fever, had no other clinical symptoms, and no gross lesion was noted on an autopsy after the end of the experiment. The FIPV gene was detected intermittently in feces and saliva regardless of the development of FIP or administration of U18666A. Conclusions: When U18666A was administered to cats experimentally infected with type I FIPV, the development of FIP might be suppressed compared with the control group. However, the number of animals with FIP is too low to establish anti-viral effect of U18666A in cats. Full article

(This article belongs to the Special Issue Feline Infectious Peritonitis)

► Show Figures

Figure 1

11 pages, 726 KB

Open AccessEditor’s ChoiceArticle

High-Resolution Composition Analysis of an Inactivated Polyvalent Foot-and-Mouth Disease Vaccine

by Leonie F. Forth, Dirk Höper, Martin Beer and Michael Eschbaumer

Pathogens 2020, 9(1), 63; https://doi.org/10.3390/pathogens9010063 - 16 Jan 2020

Cited by 9 | Viewed by 3635

Abstract

Appropriate vaccine selection is crucial in the control of foot-and-mouth disease (FMD). Vaccination can prevent clinical disease and reduces viral shedding, but there is a lack of cross-protection between the seven serotypes and their sublineages, making the selection of an adequately protective vaccine [...] Read more.

Appropriate vaccine selection is crucial in the control of foot-and-mouth disease (FMD). Vaccination can prevent clinical disease and reduces viral shedding, but there is a lack of cross-protection between the seven serotypes and their sublineages, making the selection of an adequately protective vaccine difficult. Since the exact composition of their vaccines is not consistently disclosed by all manufacturers, incompatibility of the strains used for vaccination with regionally circulating strains can cause vaccination campaigns to fail. Here, we present a deep sequencing approach for polyvalent inactivated FMD vaccines that can identify all component strains by their genome sequences. The genomes of all strains of a commercial pentavalent FMD vaccine were de novo assembled and the vaccine composition determined semi-quantitatively. The genome assembly required high stringency parameters to prevent misassemblies caused by conserved regions of the genome shared by related strains. In contrast, reference-guided assembly is only recommended in cases where the number of strains is previously known and appropriate reference sequences are available. The presented approach can be applied not only to any inactivated whole-virus FMD vaccine but also to vaccine quality testing in general and allows for better decision-making for vaccines with an unknown composition. Full article

(This article belongs to the Special Issue Diagnostics, Vaccinology and Pathogenesis of Foot-and-Mouth Disease and Other Viral Vesicular Diseases of Livestock)

► Show Figures

Figure 1

11 pages, 1438 KB

Open AccessEditor’s ChoiceArticle

Evaluation of Hypoxia-Inducible Factor-1 Alpha (HIF-1α) in Equine Sarcoid: An Immunohistochemical and Biochemical Study

by Manuela Martano, Gennaro Altamura, Karen Power, Brunella Restucci, Francesca Carella, Giuseppe Borzacchiello and Paola Maiolino

Pathogens 2020, 9(1), 58; https://doi.org/10.3390/pathogens9010058 - 14 Jan 2020

Cited by 8 | Viewed by 4155

Abstract

Background: equine sarcoids are the most frequent skin tumors in equidae worldwide. It is well known that delta bovine papillomaviruses are their causative agents. We have recently shown the presence in equine sarcoids of abnormal vessel structures, which could cause a hypoxic condition. [...] Read more.

Background: equine sarcoids are the most frequent skin tumors in equidae worldwide. It is well known that delta bovine papillomaviruses are their causative agents. We have recently shown the presence in equine sarcoids of abnormal vessel structures, which could cause a hypoxic condition. The aim of this study was to analyze the expression of hypoxia-inducible factor-1 alpha (HIF-1α) in a subset of BPV positive equine sarcoids and explore the relationship with vascular endothelial growth factor (VEGF) expression. Results: 80% of equine sarcoids showed strong cytoplasmic staining in >60% of neoplastic fibroblasts, while 20% of samples showed a moderate cytoplasmic staining in 40–60% of neoplastic fibroblasts for HIF-1α. Results of Western blotting (WB) were consistent with immunohistochemistry (IHC). Moreover, a positive correlation between HIF-1α and VEGF expression (r = 0.60, p < 0.01) was observed. Conclusion: we have shown that HIF-1α was strongly expressed in equine sarcoid. The upregulation of HIF-1α has been described in numerous tumors and can be modulated by many proteins encoded by transforming viruses. Thus, it is also possible that BPV could have a relevant role in HIF-1α pathway regulation, contributing to the development of equine sarcoids by promoting HIF-1α/VEGF mediated tumor angiogenesis. Full article

(This article belongs to the Special Issue Bovine Papillomavirus Infection)

► Show Figures

Figure 1

20 pages, 2461 KB

Open AccessEditor’s ChoiceArticle

CRISPR-cas3 of Salmonella Upregulates Bacterial Biofilm Formation and Virulence to Host Cells by Targeting Quorum-Sensing Systems

by Luqing Cui, Xiangru Wang, Deyu Huang, Yue Zhao, Jiawei Feng, Qirong Lu, Qinqin Pu, Yulian Wang, Guyue Cheng, Min Wu and Menghong Dai

Pathogens 2020, 9(1), 53; https://doi.org/10.3390/pathogens9010053 - 10 Jan 2020

Cited by 68 | Viewed by 9969

Abstract

Salmonella is recognized as one of the most common microbial pathogens worldwide. The bacterium contains the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems, providing adaptive immunity against invading foreign nucleic acids. Previous studies suggested that certain bacteria employ the Cas proteins [...] Read more.

Salmonella is recognized as one of the most common microbial pathogens worldwide. The bacterium contains the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems, providing adaptive immunity against invading foreign nucleic acids. Previous studies suggested that certain bacteria employ the Cas proteins of CRISPR-Cas systems to target their own genes, which also alters the virulence during invasion of mammals. However, whether CRISPR-Cas systems in Salmonella have similar functions during bacterial invasion of host cells remains unknown. Here, we systematically analyzed the genes that are regulated by Cas3 in a type I-E CRISPR-Cas system and the virulence changes due to the deletion of cas3 in Salmonella enterica serovar Enteritidis. Compared to the cas3 gene wild-type (cas3 WT) Salmonella strain, cas3 deletion upregulated the lsrFGBE genes in lsr (luxS regulated) operon related to quorum sensing (QS) and downregulated biofilm-forming-related genes and Salmonella pathogenicity island 1 (SPI-1) genes related to the type three secretion system (T3SS). Consistently, the biofilm formation ability was downregulated in the cas3 deletion mutant (Δcas3). The bacterial invasive and intracellular capacity of Δcas3 to host cells was also reduced, thereby increasing the survival of infected host cells and live chickens. By the transcriptome-wide screen (RNA-Seq), we found that the cas3 gene impacts a series of genes related to QS, the flagellum, and SPI-1-T3SS system, thereby altering the virulence phenotypes. As QS SPI-1-T3SS and CRISPR-Cas systems are widely distributed in the bacteria kingdom, our findings extend our understanding of virulence regulation and pathogenicity in mammalian hosts for Salmonella and potentially other bacteria. Full article

(This article belongs to the Special Issue Gene Regulation in Biofilms)

► Show Figures

Figure 1

23 pages, 1111 KB

Open AccessEditor’s ChoiceReview

Comparative Pathology of West Nile Virus in Humans and Non-Human Animals

by Alex D. Byas and Gregory D. Ebel

Pathogens 2020, 9(1), 48; https://doi.org/10.3390/pathogens9010048 - 7 Jan 2020

Cited by 61 | Viewed by 15571

Abstract

West Nile virus (WNV) continues to be a major cause of human arboviral neuroinvasive disease. Susceptible non-human vertebrates are particularly diverse, ranging from commonly affected birds and horses to less commonly affected species such as alligators. This review summarizes the pathology caused by [...] Read more.

West Nile virus (WNV) continues to be a major cause of human arboviral neuroinvasive disease. Susceptible non-human vertebrates are particularly diverse, ranging from commonly affected birds and horses to less commonly affected species such as alligators. This review summarizes the pathology caused by West Nile virus during natural infections of humans and non-human animals. While the most well-known findings in human infection involve the central nervous system, WNV can also cause significant lesions in the heart, kidneys and eyes. Time has also revealed chronic neurologic sequelae related to prior human WNV infection. Similarly, neurologic disease is a prominent manifestation of WNV infection in most non-human non-host animals. However, in some avian species, which serve as the vertebrate host for WNV maintenance in nature, severe systemic disease can occur, with neurologic, cardiac, intestinal and renal injury leading to death. The pathology seen in experimental animal models of West Nile virus infection and knowledge gains on viral pathogenesis derived from these animal models are also briefly discussed. A gap in the current literature exists regarding the relationship between the neurotropic nature of WNV in vertebrates, virus propagation and transmission in nature. This and other knowledge gaps, and future directions for research into WNV pathology, are addressed. Full article

(This article belongs to the Special Issue Pathogenesis of West Nile Virus)

► Show Figures

Figure 1

18 pages, 1507 KB

Open AccessEditor’s ChoiceReview

Understanding Flavivirus Capsid Protein Functions: The Tip of the Iceberg

by Stephanea Sotcheff and Andrew Routh

Pathogens 2020, 9(1), 42; https://doi.org/10.3390/pathogens9010042 - 5 Jan 2020

Cited by 42 | Viewed by 10540

Abstract

Flaviviruses are enveloped positive-sense single-stranded RNA arboviruses, infectious to humans and many other animals and are transmitted primarily via tick or mosquito vectors. Capsid is the primary structural protein to interact with viral genome within virus particles and is therefore necessary for efficient [...] Read more.

Flaviviruses are enveloped positive-sense single-stranded RNA arboviruses, infectious to humans and many other animals and are transmitted primarily via tick or mosquito vectors. Capsid is the primary structural protein to interact with viral genome within virus particles and is therefore necessary for efficient packaging. However, in cells, capsid interacts with many proteins and nucleic acids and we are only beginning to understand the broad range of functions of flaviviral capsids. It is known that capsid dimers interact with the membrane of lipid droplets, aiding in both viral packaging and storage of capsid prior to packaging. However, capsid dimers can bind a range of nucleic acid templates in vitro, and likely interact with a range of targets during the flavivirus lifecycle. Capsid may interact with host RNAs, resulting in altered RNA splicing and RNA transcription. Capsid may also bind short interfering-RNAs and has been proposed to sequester these species to protect flaviviruses from the invertebrate siRNA pathways. Capsid can also be found in the nucleolus, where it wreaks havoc on ribosome biogenesis. Here we review flavivirus capsid structure, nucleic acid interactions and how these give rise to multiple functions. We also discuss how these features might be exploited either in the design of effective antivirals or novel vaccine strategies. Full article

(This article belongs to the Special Issue Vaccines against Alphaviruses and Flaviviruses)

► Show Figures

Figure 1

15 pages, 1301 KB

Open AccessEditor’s ChoiceArticle

Toxoplasma gondii Recombinant antigen AMA1: Diagnostic Utility of Protein Fragments for the Detection of IgG and IgM Antibodies

by Bartłomiej Ferra, Lucyna Holec-Gąsior, Justyna Gatkowska, Bożena Dziadek and Katarzyna Dzitko

Pathogens 2020, 9(1), 43; https://doi.org/10.3390/pathogens9010043 - 5 Jan 2020

Cited by 17 | Viewed by 5400

Abstract

Toxoplasma gondii is an important zoonotic protozoan that infects a wide variety of vertebrates as intermediate hosts. For this reason, the diagnosis of this disease is very important and requires continuous improvement. One possibility is to use recombinant antigens in serological tests. Apical [...] Read more.

Toxoplasma gondii is an important zoonotic protozoan that infects a wide variety of vertebrates as intermediate hosts. For this reason, the diagnosis of this disease is very important and requires continuous improvement. One possibility is to use recombinant antigens in serological tests. Apical membrane antigen 1 (AMA1), a protein located in specific secretory organelles (micronemes) of T. gondii, is very interesting in regard to its potential diagnostic utility. In the present study, we attempted to identify a fragment of the AMA1 protein with a high sensitivity and specificity for the serological diagnosis of human toxoplasmosis. The full-length AMA1 and two different fragments (AMA1N and AMA1C) were produced using an Escherichia coli expression system. After purification by metal affinity chromatography, recombinant proteins were tested for their utility as antigens in enzyme-linked immunosorbent assays (ELISAs) for the detection of IgG and IgM anti-T. gondii antibodies in human and mouse immune sera. Our data demonstrate that the full-length AMA1 recombinant antigen (corresponding to amino acid residues 67–569 of the native protein) has a better diagnostic potential than its N- or C-terminal fragments. This recombinant protein strongly interacts with specific anti-T. gondii IgG (99.4%) and IgM (80.0%) antibodies, and may be used for developing new tools for diagnostics of toxoplasmosis. Full article

(This article belongs to the Section Human Pathogens)

► Show Figures

Graphical abstract

17 pages, 1925 KB

Open AccessEditor’s ChoiceArticle

Analysis of Porcine Pro- and Anti-Inflammatory Cytokine Induction by S. suis In Vivo and In Vitro

by Florian S. Hohnstein, Marita Meurer, Nicole de Buhr, Maren von Köckritz-Blickwede, Christoph G. Baums, Gottfried Alber and Nicole Schütze

Pathogens 2020, 9(1), 40; https://doi.org/10.3390/pathogens9010040 - 3 Jan 2020

Cited by 17 | Viewed by 5664

Abstract

Weaning piglets are susceptible to the invasive Streptococcus (S.) suis infection, which can result in septicemia. The aim of this study was to investigate the cytokine profile induced upon S. suis infection of blood, to determine the cellular sources of those cytokines, and [...] Read more.

Weaning piglets are susceptible to the invasive Streptococcus (S.) suis infection, which can result in septicemia. The aim of this study was to investigate the cytokine profile induced upon S. suis infection of blood, to determine the cellular sources of those cytokines, and to study the potential effects of the induced cytokines on bacterial killing. We measured TNF-α, IL-6, IFN-γ, IL-17A and IL-10 after an experimental intravenous infection with S. suis serotype 2 in vivo, and analyzed whole blood, peripheral blood mononuclear cells (PBMC) and separated leukocytes to identify the cytokine-producing cell type(s). In addition, we used a reconstituted whole blood assay to investigate the effect of TNF-α on bacterial killing in the presence of different S. suis-specific IgG levels. An increase in IL-6 and IL-10, but not in IFN-γ or IL-17A, was observed in two of three piglets with pronounced bacteremia 16 to 20 h after infection, but not in piglets with controlled bacteremia. Our results confirmed previous findings that S. suis induces TNF-α and IL-6 and could demonstrate that TNF-α is produced by monocytes in vitro. We further found that IL-10 induction resulted in reduced secretion of TNF-α and IL-6. Rapid induction of TNF-α was, however, not crucial for in vitro bacterial killing, not even in the absence of specific IgG. Full article

(This article belongs to the Special Issue Update on Streptococcus suis Research and Prevention in the Era of Antibiotic Restriction - 4th International Workshop on Streptococcus suis)

► Show Figures

Graphical abstract

19 pages, 2112 KB

Open AccessEditor’s ChoiceArticle

The Cell-Cycle Regulatory Protein p21^CIP1/WAF1 Is Required for Cytolethal Distending Toxin (Cdt)-Induced Apoptosis

by Bruce J. Shenker, Lisa M. Walker, Ali Zekavat, Robert H. Weiss and Kathleen Boesze-Battaglia

Pathogens 2020, 9(1), 38; https://doi.org/10.3390/pathogens9010038 - 2 Jan 2020

Cited by 15 | Viewed by 3882

Abstract

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21^CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21 [...] Read more.

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21^CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21^CIP1/WAF1 in lymphoid cell lines, Jurkat and MyLa, and in primary human lymphocytes. These increases were dependent upon CdtB’s ability to function as a phosphatidylinositol (PI) 3,4,5-triphosphate (PIP3) phosphatase. It is noteworthy that Cdt-induced increases in the levels of p21^CIP1/WAF1 were accompanied by a significant decline in the levels of phosphorylated p21^CIP1/WAF1. The significance of Cdt-induced p21^CIP1/WAF1 increase was assessed by preventing these changes with a two-pronged approach; pre-incubation with the novel p21^CIP1/WAF1 inhibitor, UC2288, and development of a p21^CIP1/WAF1-deficient cell line (Jurkat^p21−) using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 gene editing. UC2288 blocked toxin-induced increases in p21^CIP1/WAF1, and Jurkat^WT cells treated with this inhibitor exhibited reduced susceptibility to Cdt-induced apoptosis. Likewise, Jurkat^p21− cells failed to undergo toxin-induced apoptosis. The linkage between Cdt, p21^CIP1/WAF1, and apoptosis was further established by demonstrating that Cdt-induced increases in levels of the pro-apoptotic proteins Bid, Bax, and Bak were dependent upon p21^CIP1/WAF1 as these changes were not observed in Jurkat^p21− cells. Finally, we determined that the p21^CIP1/WAF1 increases were dependent upon toxin-induced increases in the level and activity of the chaperone heat shock protein (HSP) 90. We propose that p21^CIP1/WAF1 plays a key pro-apoptotic role in mediating Cdt-induced toxicity. Full article

(This article belongs to the Special Issue Aggregatibacter actinomycetemcomitans—Gram-Negative Bacterial Pathogen)

► Show Figures

Figure 1

13 pages, 4214 KB

Open AccessEditor’s ChoiceArticle

Comparison of the Pathogenicity of Two Different Branches of Senecavirus a Strain in China

by Huawei Zhang, Pin Chen, Genxi Hao, Wenqiang Liu, Huanchun Chen, Ping Qian and Xiangmin Li

Pathogens 2020, 9(1), 39; https://doi.org/10.3390/pathogens9010039 - 2 Jan 2020

Cited by 23 | Viewed by 3559

Abstract

Senecavirus A (SVA), an emerging infectious disease, is associated with the porcine idiopathic vesicular disease. Here, the pathogenesis of different strains of SVA was investigated in growing-finishing pigs. We aimed to evaluate the replication characteristics, virus particle morphology, clinical signs, and vesicular lesions [...] Read more.

Senecavirus A (SVA), an emerging infectious disease, is associated with the porcine idiopathic vesicular disease. Here, the pathogenesis of different strains of SVA was investigated in growing-finishing pigs. We aimed to evaluate the replication characteristics, virus particle morphology, clinical signs, and vesicular lesions in comparison with two different strains of SVA. The animals were infected with SVA HB-CH-2016 or CH/AH-02/2017 by intranasal routes (3 mL, 10⁹TCID₅₀/mL) and monitored daily for 14 days post-inoculation (dpi) for clinical signs and vesicular lesions. Viremia or viral shedding was detected in the blood, fecal swab, and nasal swab samples. Results showed no distinct differences in plaque size, replication ability, and characteristic virions between SVA HB-CH-2016 and CH/AH-02/2017 strains. Animal experimental results showed that both SVA CH/AH-02/2017 and SVA HB-CH-2016 could infect pigs. However, an obvious difference in the pathogenicity and dynamics of infection was observed between SVA HB-CH-2016 and CH/AH-02/2017 strains. The pathogenesis of SVA CH/AH-02/2017 was similar to that of published results of USA strains, whereas the SVA HB-CH-2016 strain had low pathogenicity to pigs. Clinical signs and vesicular lesions were observed in SVA CH/AH-02/2017-infected pigs. Additionally, the different branches of SVA should be capable of inducing broad cross-reactive neutralizing antibodies, which play an important role in clearing the SVA virus. This study of animal models for SVA infection will be beneficial to develop vaccines and antivirals. Full article

(This article belongs to the Section Animal Pathogens)

► Show Figures

Figure 1

23 pages, 4073 KB

Open AccessEditor’s ChoiceArticle

The Xylella fastidiosa-Resistant Olive Cultivar “Leccino” Has Stable Endophytic Microbiota during the Olive Quick Decline Syndrome (OQDS)

by Marzia Vergine, Joana B. Meyer, Massimiliano Cardinale, Erika Sabella, Martin Hartmann, Paolo Cherubini, Luigi De Bellis and Andrea Luvisi

Pathogens 2020, 9(1), 35; https://doi.org/10.3390/pathogens9010035 - 31 Dec 2019

Cited by 48 | Viewed by 8135

Abstract

Xylella fastidiosa is a highly virulent pathogen that causes Olive Quick Decline Syndrome (OQDS), which is currently devastating olive plantations in the Salento region (Apulia, Southern Italy). We explored the microbiome associated with X. fastidiosa-infected (Xf-infected) and -uninfected (Xf [...] Read more.

Xylella fastidiosa is a highly virulent pathogen that causes Olive Quick Decline Syndrome (OQDS), which is currently devastating olive plantations in the Salento region (Apulia, Southern Italy). We explored the microbiome associated with X. fastidiosa-infected (Xf-infected) and -uninfected (Xf-uninfected) olive trees in Salento, to assess the level of dysbiosis and to get first insights into the potential role of microbial endophytes in protecting the host from the disease. The resistant cultivar “Leccino” was compared to the susceptible cultivar “Cellina di Nardò”, in order to identify microbial taxa and parameters potentially involved in resistance mechanisms. Metabarcoding of 16S rRNA genes and fungal ITS2 was used to characterize both total and endophytic microbiota in olive branches and leaves. “Cellina di Nardò” showed a drastic dysbiosis after X. fastidiosa infection, while “Leccino” (both infected and uninfected) maintained a similar microbiota. The genus Pseudomonas dominated all “Leccino” and Xf-uninfected “Cellina di Nardò” trees, whereas Ammoniphilus prevailed in Xf-infected “Cellina di Nardò”. Diversity of microbiota in Xf-uninfected “Leccino” was higher than in Xf-uninfected “Cellina di Nardò”. Several bacterial taxa specifically associated with “Leccino” showed potential interactions with X. fastidiosa. The maintenance of a healthy microbiota with higher diversity and the presence of cultivar-specific microbes might support the resistance of “Leccino” to X. fastidiosa. Such beneficial bacteria might be isolated in the future for biological treatment of the OQDS. Full article

(This article belongs to the Section Plant Pathogens)

► Show Figures

Figure 1

19 pages, 2039 KB

Open AccessEditor’s ChoiceArticle

Membrane Binding, Cellular Cholesterol Content and Resealing Capacity Contribute to Epithelial Cell Damage Induced by Suilysin of Streptococcus suis

by Désirée Vötsch, Maren Willenborg, Walter M.R. Oelemann, Graham Brogden and Peter Valentin-Weigand

Pathogens 2020, 9(1), 33; https://doi.org/10.3390/pathogens9010033 - 30 Dec 2019

Cited by 7 | Viewed by 3698

Abstract

Streptococcus (S.) suis is a major cause of economic losses in the pig industry worldwide and is an emerging zoonotic pathogen. One important virulence-associated factor is suilysin (SLY), a toxin that belongs to the family of cholesterol-dependent pore-forming cytolysins (CDC). However, [...] Read more.

Streptococcus (S.) suis is a major cause of economic losses in the pig industry worldwide and is an emerging zoonotic pathogen. One important virulence-associated factor is suilysin (SLY), a toxin that belongs to the family of cholesterol-dependent pore-forming cytolysins (CDC). However, the precise role of SLY in host–pathogen interactions is still unclear. Here, we investigated the susceptibility of different respiratory epithelial cells to SLY, including immortalized cell lines (HEp-2 and NPTr cells), which are frequently used in in vitro studies on S. suis virulence mechanisms, as well as primary porcine respiratory cells, which represent the first line of barrier during S. suis infections. SLY-induced cell damage was determined by measuring the release of lactate dehydrogenase after infection with a virulent S. suis serotype 2 strain, its isogenic SLY-deficient mutant strain, or treatment with the recombinant protein. HEp-2 cells were most susceptible, whereas primary epithelial cells were hardly affected by the toxin. This prompted us to study possible explanations for these differences. We first investigated the binding capacity of SLY using flow cytometry analysis. Since binding and pore-formation of CDC is dependent on the membrane composition, we also determined the cellular cholesterol content of the different cell types using TLC and HPLC. Finally, we examined the ability of those cells to reseal SLY-induced pores using flow cytometry analysis. Our results indicated that the amount of membrane-bound SLY, the cholesterol content of the cells, as well as their resealing capacity all affect the susceptibility of the different cells regarding the effects of SLY. These findings underline the differences of in vitro pathogenicity models and may further help to dissect the biological role of SLY during S. suis infections. Full article

(This article belongs to the Special Issue Update on Streptococcus suis Research and Prevention in the Era of Antibiotic Restriction - 4th International Workshop on Streptococcus suis)

► Show Figures

Figure 1

22 pages, 1290 KB

Open AccessEditor’s ChoiceReview

The Notorious Soilborne Pathogenic Fungus Sclerotinia sclerotiorum: An Update on Genes Studied with Mutant Analysis

by Shitou Xia, Yan Xu, Ryan Hoy, Julia Zhang, Lei Qin and Xin Li

Pathogens 2020, 9(1), 27; https://doi.org/10.3390/pathogens9010027 - 27 Dec 2019

Cited by 49 | Viewed by 12256

Abstract

Ascomycete Sclerotinia sclerotiorum (Lib.) de Bary is one of the most damaging soilborne fungal pathogens affecting hundreds of plant hosts, including many economically important crops. Its genomic sequence has been available for less than a decade, and it was recently updated with higher [...] Read more.

Ascomycete Sclerotinia sclerotiorum (Lib.) de Bary is one of the most damaging soilborne fungal pathogens affecting hundreds of plant hosts, including many economically important crops. Its genomic sequence has been available for less than a decade, and it was recently updated with higher completion and better gene annotation. Here, we review key molecular findings on the unique biology and pathogenesis process of S. sclerotiorum, focusing on genes that have been studied in depth using mutant analysis. Analyses of these genes have revealed critical players in the basic biological processes of this unique pathogen, including mycelial growth, appressorium establishment, sclerotial formation, apothecial and ascospore development, and virulence. Additionally, the synthesis has uncovered gaps in the current knowledge regarding this fungus. We hope that this review will serve to build a better current understanding of the biology of this under-studied notorious soilborne pathogenic fungus. Full article

(This article belongs to the Section Plant Pathogens)

► Show Figures

Figure 1

14 pages, 5535 KB

Open AccessEditor’s ChoiceArticle

Genome-Wide Analysis of Cyclophilin Proteins in 21 Oomycetes

by Yan Zhang, Kyle Fletcher, Rongkui Han, Richard Michelmore and Ruiwu Yang

Pathogens 2020, 9(1), 24; https://doi.org/10.3390/pathogens9010024 - 26 Dec 2019

Cited by 3 | Viewed by 4066

Abstract

Cyclophilins (CYPs), a highly-conserved family of proteins, belong to a subgroup of immunophilins. Ubiquitous in eukaryotes and prokaryotes, CYPs have peptidyl-prolyl cis–trans isomerase (PPIase) activity and have been implicated as virulence factors in plant pathogenesis by oomycetes. We identified 16 CYP orthogroups from [...] Read more.

Cyclophilins (CYPs), a highly-conserved family of proteins, belong to a subgroup of immunophilins. Ubiquitous in eukaryotes and prokaryotes, CYPs have peptidyl-prolyl cis–trans isomerase (PPIase) activity and have been implicated as virulence factors in plant pathogenesis by oomycetes. We identified 16 CYP orthogroups from 21 diverse oomycetes. Each species was found to encode 15 to 35 CYP genes. Three of these orthogroups contained proteins with signal peptides at the N-terminal end, suggesting a role in secretion. Multidomain analysis revealed five conserved motifs of the CYP domain of oomycetes shared with other eukaryotic PPIases. Expression analysis of CYP proteins in different asexual life stages of the hemibiotrophic Phytophthora infestans and the biotrophic Plasmopara halstedii demonstrated distinct expression profiles between life stages. In addition to providing detailed comparative information on the CYPs in multiple oomycetes, this study identified candidate CYP effectors that could be the foundation for future studies of virulence. Full article

► Show Figures

Figure 1

23 pages, 5544 KB

Open AccessEditor’s ChoiceArticle

Chromosomal Conjugative and Mobilizable Elements in Streptococcus suis: Major Actors in the Spreading of Antimicrobial Resistance and Bacteriocin Synthesis Genes

by Virginie Libante, Yves Nombre, Charles Coluzzi, Johan Staub, Gérard Guédon, Marcelo Gottschalk, Sarah Teatero, Nahuel Fittipaldi, Nathalie Leblond-Bourget and Sophie Payot

Pathogens 2020, 9(1), 22; https://doi.org/10.3390/pathogens9010022 - 25 Dec 2019

Cited by 37 | Viewed by 6024

Abstract

Streptococcus suis is a zoonotic pathogen suspected to be a reservoir of antimicrobial resistance (AMR) genes. The genomes of 214 strains of 27 serotypes were screened for AMR genes and chromosomal Mobile Genetic Elements (MGEs), in particular Integrative Conjugative Elements (ICEs) and Integrative [...] Read more.

Streptococcus suis is a zoonotic pathogen suspected to be a reservoir of antimicrobial resistance (AMR) genes. The genomes of 214 strains of 27 serotypes were screened for AMR genes and chromosomal Mobile Genetic Elements (MGEs), in particular Integrative Conjugative Elements (ICEs) and Integrative Mobilizable Elements (IMEs). The functionality of two ICEs that host IMEs carrying AMR genes was investigated by excision tests and conjugation experiments. In silico search revealed 416 ICE-related and 457 IME-related elements. These MGEs exhibit an impressive diversity and plasticity with tandem accretions, integration of ICEs or IMEs inside ICEs and recombination between the elements. All of the detected 393 AMR genes are carried by MGEs. As previously described, ICEs are major vehicles of AMR genes in S. suis. Tn5252-related ICEs also appear to carry bacteriocin clusters. Furthermore, whereas the association of IME-AMR genes has never been described in S. suis, we found that most AMR genes are actually carried by IMEs. The autonomous transfer of an ICE to another bacterial species (Streptococcus thermophilus)—leading to the cis-mobilization of an IME carrying tet(O)—was obtained. These results show that besides ICEs, IMEs likely play a major role in the dissemination of AMR genes in S. suis. Full article

(This article belongs to the Special Issue Update on Streptococcus suis Research and Prevention in the Era of Antibiotic Restriction - 4th International Workshop on Streptococcus suis)

► Show Figures

Figure 1

16 pages, 969 KB

Open AccessEditor’s ChoiceReview

Chloroplasts and Plant Immunity: Where Are the Fungal Effectors?

by Matthias Kretschmer, Djihane Damoo, Armin Djamei and James Kronstad

Pathogens 2020, 9(1), 19; https://doi.org/10.3390/pathogens9010019 - 24 Dec 2019

Cited by 90 | Viewed by 13352

Abstract

Chloroplasts play a central role in plant immunity through the synthesis of secondary metabolites and defense compounds, as well as phytohormones, such as jasmonic acid and salicylic acid. Additionally, chloroplast metabolism results in the production of reactive oxygen species and nitric oxide as [...] Read more.

Chloroplasts play a central role in plant immunity through the synthesis of secondary metabolites and defense compounds, as well as phytohormones, such as jasmonic acid and salicylic acid. Additionally, chloroplast metabolism results in the production of reactive oxygen species and nitric oxide as defense molecules. The impact of viral and bacterial infections on plastids and chloroplasts has been well documented. In particular, bacterial pathogens are known to introduce effectors specifically into chloroplasts, and many viral proteins interact with chloroplast proteins to influence viral replication and movement, and plant defense. By contrast, clear examples are just now emerging for chloroplast-targeted effectors from fungal and oomycete pathogens. In this review, we first present a brief overview of chloroplast contributions to plant defense and then discuss examples of connections between fungal interactions with plants and chloroplast function. We then briefly consider well-characterized bacterial effectors that target chloroplasts as a prelude to discussing the evidence for fungal effectors that impact chloroplast activities. Full article

(This article belongs to the Special Issue Pathogenesis of Fungal and Bacterial Microbes)

► Show Figures

Figure 1

11 pages, 1358 KB

Open AccessEditor’s ChoiceCommunication

Human Microglia Respond to Malaria-Induced Extracellular Vesicles

by Smart Ikechukwu Mbagwu, Nils Lannes, Michael Walch, Luis Filgueira and Pierre-Yves Mantel

Pathogens 2020, 9(1), 21; https://doi.org/10.3390/pathogens9010021 - 24 Dec 2019

Cited by 28 | Viewed by 5143

Abstract

Microglia are the chief immune cells of the brain and have been reported to be activated in severe malaria. Their activation may drive towards neuroinflammation in cerebral malaria. Malaria-infected red blood cell derived-extracellular vesicles (MiREVs) are produced during the blood stage of malaria [...] Read more.

Microglia are the chief immune cells of the brain and have been reported to be activated in severe malaria. Their activation may drive towards neuroinflammation in cerebral malaria. Malaria-infected red blood cell derived-extracellular vesicles (MiREVs) are produced during the blood stage of malaria infection. They mediate intercellular communication and immune regulation, among other functions. During cerebral malaria, the breakdown of the blood–brain barrier can promote the migration of substances such as MiREVs from the periphery into the brain, targeting cells such as microglia. Microglia and extracellular vesicle interactions in different pathological conditions have been reported to induce neuroinflammation. Unlike in astrocytes, microglia–extracellular vesicle interaction has not yet been described in malaria infection. Therefore, in this study, we aimed to investigate the uptake of MiREVs by human microglia cells and their cytokine response. Human blood monocyte-derived microglia (MoMi) were generated from buffy coats of anonymous healthy donors using Ficoll-Paque density gradient centrifugation. The MiREVs were isolated from the Plasmodium falciparum cultures. They were purified by ultracentrifugation and labeled with PKH67 green fluorescent dye. The internalization of MiREVs by MoMi was observed after 4 h of co-incubation on coverslips placed in a 24-well plate at 37 °C using confocal microscopy. Cytokine-gene expression was investigated using rt-qPCR, following the stimulation of the MoMi cells with supernatants from the parasite cultures at 2, 4, and 24 h, respectively. MiREVs were internalized by the microglia and accumulated in the perinuclear region. MiREVs-treated cells increased gene expression of the inflammatory cytokine TNFα and reduced gene expression of the immune suppressive IL-10. Overall, the results indicate that MiREVs may act on microglia, which would contribute to enhanced inflammation in cerebral malaria. Full article

► Show Figures

Graphical abstract

11 pages, 627 KB

Open AccessEditor’s ChoiceReview

Cancer-Associated Fibroblasts in Undifferentiated Nasopharyngeal Carcinoma: A Putative Role for the EBV-Encoded Oncoprotein, LMP1

by Mhairi A. Morris

Pathogens 2020, 9(1), 8; https://doi.org/10.3390/pathogens9010008 - 20 Dec 2019

Cited by 12 | Viewed by 5138

Abstract

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein–Barr virus (EBV) infection, and biopsies display variable levels of expression of the viral oncoprotein, latent membrane protein 1 (LMP1). Emerging evidence suggests an important role for cancer-associated fibroblasts (CAFs) in the NPC tumour microenvironment, [...] Read more.

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein–Barr virus (EBV) infection, and biopsies display variable levels of expression of the viral oncoprotein, latent membrane protein 1 (LMP1). Emerging evidence suggests an important role for cancer-associated fibroblasts (CAFs) in the NPC tumour microenvironment, yet the interaction between the virus, its latent gene products and the recruitment and activation of CAFs in the NPC tumour stroma remains unclear. This short review will discuss the current evidence for the importance of CAFs in NPC pathogenesis and outline a putative role for the EBV-encoded oncoprotein, LMP1, in governing tumour–stromal interactions. Full article

(This article belongs to the Section Human Pathogens)

► Show Figures

Figure 1

27 pages, 760 KB

Open AccessEditor’s ChoiceReview

Atypical, Yet Not Infrequent, Infections with Neisseria Species

by Maria Victoria Humbert and Myron Christodoulides

Pathogens 2020, 9(1), 10; https://doi.org/10.3390/pathogens9010010 - 20 Dec 2019

Cited by 54 | Viewed by 16790

Abstract

Neisseria species are extremely well-adapted to their mammalian hosts and they display unique phenotypes that account for their ability to thrive within niche-specific conditions. The closely related species N. gonorrhoeae and N. meningitidis are the only two species of the genus recognized as [...] Read more.

Neisseria species are extremely well-adapted to their mammalian hosts and they display unique phenotypes that account for their ability to thrive within niche-specific conditions. The closely related species N. gonorrhoeae and N. meningitidis are the only two species of the genus recognized as strict human pathogens, causing the sexually transmitted disease gonorrhea and meningitis and sepsis, respectively. Gonococci colonize the mucosal epithelium of the male urethra and female endo/ectocervix, whereas meningococci colonize the mucosal epithelium of the human nasopharynx. The pathophysiological host responses to gonococcal and meningococcal infection are distinct. However, medical evidence dating back to the early 1900s demonstrates that these two species can cross-colonize anatomical niches, with patients often presenting with clinically-indistinguishable infections. The remaining Neisseria species are not commonly associated with disease and are considered as commensals within the normal microbiota of the human and animal nasopharynx. Nonetheless, clinical case reports suggest that they can behave as opportunistic pathogens. In this review, we describe the diversity of the genus Neisseria in the clinical context and raise the attention of microbiologists and clinicians for more cautious approaches in the diagnosis and treatment of the many pathologies these species may cause. Full article

(This article belongs to the Special Issue Neisseria gonorrhoeae Infections)

► Show Figures

Figure 1

22 pages, 1888 KB

Open AccessEditor’s ChoiceReview

The Role of Pseudomonas aeruginosa Lipopolysaccharide in Bacterial Pathogenesis and Physiology

by Steven M. Huszczynski, Joseph S. Lam and Cezar M. Khursigara

Pathogens 2020, 9(1), 6; https://doi.org/10.3390/pathogens9010006 - 19 Dec 2019

Cited by 148 | Viewed by 18615

Abstract

The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is [...] Read more.

The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is a key molecule on the bacterial cell wall that is recognized by the host to deploy an immune defence in order to neutralize invading pathogens. However, LPS also promotes bacterial survival in a host environment by protecting the bacteria from these threats. This review explores the relationship between the different LPS glycoforms of the opportunistic pathogen Pseudomonas aeruginosa and the ability of this organism to cause persistent infections, especially in the genetic disease cystic fibrosis. We also discuss the role of LPS in facilitating biofilm formation, antibiotic resistance, and how LPS may be targeted by new antimicrobial therapies. Full article

(This article belongs to the Special Issue Pathogenesis of Fungal and Bacterial Microbes)

► Show Figures

Figure 1

15 pages, 2360 KB

Open AccessEditor’s ChoiceArticle

Genetic Changes in Experimental Populations of a Hybrid in the Cryptococcus neoformans Species Complex

by Kelly Dong, Man You and Jianping Xu

Pathogens 2020, 9(1), 3; https://doi.org/10.3390/pathogens9010003 - 18 Dec 2019

Cited by 17 | Viewed by 3184

Abstract

Hybrids between Cryptococcus neoformans and Cryptococcus deneoformans are commonly found in patients and the environment. However, the genetic stability of these hybrids remains largely unknown. Here, we established mutation accumulation lines of a diploid C. neoformans × C. deneoformans laboratory hybrid and analyzed [...] Read more.

Hybrids between Cryptococcus neoformans and Cryptococcus deneoformans are commonly found in patients and the environment. However, the genetic stability of these hybrids remains largely unknown. Here, we established mutation accumulation lines of a diploid C. neoformans × C. deneoformans laboratory hybrid and analyzed the genotypes at 33 markers distributed across all 14 chromosomes. Our analyses found that under standard culture conditions, heterozygosity at most loci was maintained over 800 mitotic generations, with an estimated 6.44 × 10⁻⁵ loss-of-heterozygosity (LoH) event per mitotic division. However, under fluconazole stress, the observed LoH frequency increased by > 50 folds for the two markers on Chromosome 1, all due to the loss of the fluconazole susceptible allele on this chromosome. Flow cytometry analyses showed that after the 40th transfer (120 days), 19 of the 20 lines maintained the original ploidy level (2N), while one line was between 2N and 3N. The combined flow cytometry, genotyping at 33 markers, and quantitative PCR analyses showed the allelic loss was compensated for by amplification of the resistant ERG11 allele in eight of the ten fluconazole-stress lines. Our results suggest that hybrids in C. neoformans species complex are generally stable but that they can undergo rapid adaptation to environmental stresses through LoH and gene duplication. Full article

(This article belongs to the Special Issue Pathogenesis of Fungal and Bacterial Microbes)

► Show Figures

Figure 1

59 pages, 2178 KB

Open AccessEditor’s ChoiceReview

Lyme Disease Frontiers: Reconciling Borrelia Biology and Clinical Conundrums

by Vladimir V. Bamm, Jordan T. Ko, Iain L. Mainprize, Victoria P. Sanderson and Melanie K. B. Wills

Pathogens 2019, 8(4), 299; https://doi.org/10.3390/pathogens8040299 - 16 Dec 2019

Cited by 30 | Viewed by 20679

Abstract

Lyme disease is a complex tick-borne zoonosis that poses an escalating public health threat in several parts of the world, despite sophisticated healthcare infrastructure and decades of effort to address the problem. Concepts like the true burden of the illness, from incidence rates [...] Read more.

Lyme disease is a complex tick-borne zoonosis that poses an escalating public health threat in several parts of the world, despite sophisticated healthcare infrastructure and decades of effort to address the problem. Concepts like the true burden of the illness, from incidence rates to longstanding consequences of infection, and optimal case management, also remain shrouded in controversy. At the heart of this multidisciplinary issue are the causative spirochetal pathogens belonging to the Borrelia Lyme complex. Their unusual physiology and versatile lifestyle have challenged microbiologists, and may also hold the key to unlocking mysteries of the disease. The goal of this review is therefore to integrate established and emerging concepts of Borrelia biology and pathogenesis, and position them in the broader context of biomedical research and clinical practice. We begin by considering the conventions around diagnosing and characterizing Lyme disease that have served as a conceptual framework for the discipline. We then explore virulence from the perspective of both host (genetic and environmental predispositions) and pathogen (serotypes, dissemination, and immune modulation), as well as considering antimicrobial strategies (lab methodology, resistance, persistence, and clinical application), and borrelial adaptations of hypothesized medical significance (phenotypic plasticity or pleomorphy). Full article

(This article belongs to the Special Issue Pathogenesis of Fungal and Bacterial Microbes)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Editor’s Choice Articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI