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Pathogens, Volume 8, Issue 2 (June 2019)

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Cover Story (view full-size image) A model of the interactions between emerging periodontal bacteria with neutrophils in the gingival [...] Read more.
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Open AccessReview
Campylobacter at the Human–Food Interface: The African Perspective
Received: 15 April 2019 / Revised: 18 June 2019 / Accepted: 20 June 2019 / Published: 25 June 2019
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Abstract
The foodborne pathogen Campylobacter is a major cause of human gastroenteritis, accounting for an estimated annual 96 million cases worldwide. Assessment of the true burden of Campylobacter in the African context is handicapped by the under-reporting of diarrhoeal incidents and ineffective monitoring and [...] Read more.
The foodborne pathogen Campylobacter is a major cause of human gastroenteritis, accounting for an estimated annual 96 million cases worldwide. Assessment of the true burden of Campylobacter in the African context is handicapped by the under-reporting of diarrhoeal incidents and ineffective monitoring and surveillance programmes of foodborne illnesses, as well as the minimal attention given to Campylobacter as a causative agent of diarrhoea. The present review of the literature highlights the variability in the reported occurrence of Campylobacter in humans and animal food sources across different countries and regions in Africa. Campylobacter infection is particularly prevalent in the paediatric population and has been isolated from farm animals, particularly poultry, and foods of animal origin. The reported prevalence of Campylobacter in children under the age of five years ranges from 2% in Sudan to 21% in South Africa. In poultry, the prevalence ranges from 14.4% in Ghana to 96% in Algeria. This review also highlights the alarming trend of increased Campylobacter resistance to clinically important antimicrobials, such as ciprofloxacin and erythromycin, in humans and food animals in Africa. This review adds to our understanding of the global epidemiology of Campylobacter at the human–food animal interface, with an emphasis from the African perspective. Interinstitutional and intersectoral collaborations, as well as the adoption of the One Health approach, would be useful in bridging the gaps in the epidemiological knowledge of Campylobacter in Africa. Full article
(This article belongs to the Special Issue Zoonotic Diseases and One Health)
Open AccessArticle
Antimicrobial Resistance, Virulence Factors, and Pathotypes of Escherichia coli Isolated from Drinking Water Sources in Jordan
Received: 17 May 2019 / Revised: 19 June 2019 / Accepted: 21 June 2019 / Published: 25 June 2019
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Abstract
The study investigated the prevalence of potentially pathogenic and drug resistant Escherichia coli among drinking water sources in Jordan. A total of 109 confirmed E. coli isolates were analyzed. Antimicrobial susceptibility testing was done using the Kirby Bauer disk diffusion method. Phenotypic identification [...] Read more.
The study investigated the prevalence of potentially pathogenic and drug resistant Escherichia coli among drinking water sources in Jordan. A total of 109 confirmed E. coli isolates were analyzed. Antimicrobial susceptibility testing was done using the Kirby Bauer disk diffusion method. Phenotypic identification of extended spectrum beta-lactamase (ESBL) and carbapenemase production was done using the double disk synergy test and the modified Hodge test, respectively. Isolates’ plasmid profiles were determined by gel electrophoresis. PCR was used for detection of virulence and resistance genes. Overall, 22.0% of the isolates were potentially intestinal pathogenic E. coli (IPEC); namely enteroaggregative E. coli (16.5%), enteropathogenic E. coli (2.8%), enteroinvasive E. coli (1.8%), and enterohemorrhagic E. coli (0.9%). A third of the isolates were multi-drug resistant. The highest rates of antimicrobials resistance were observed against ampicillin (93.6%) and sulfamethoxazole/trimethoprim (41.3%). All isolates were susceptible to imipenem, meropenem, doripenem and tigecycline. The prevalence of ESBL and carbapenemase producers was 54.1% and 2.8%, respectively. BlaVIM was the most prevalent resistance gene (68.8%), followed by blaCTX (50.5%), blaTEM (45.9%), blaNDM (11%), blaKPC (4.6%), and blaSHV (0.9%). Fifty-eight (53.2%) isolates contained one or more plasmid ranging from 1.0 to 8.0 kbp. Overall, high prevalence of potentially pathogenic and resistant isolates was observed. Full article
(This article belongs to the Section Waterborne/Foodborne/Airborne Pathogens)
Open AccessArticle
The Antiviral Effect of Indonesian Medicinal Plant Extracts Against Dengue Virus In Vitro and In Silico
Received: 7 May 2019 / Revised: 18 June 2019 / Accepted: 19 June 2019 / Published: 22 June 2019
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Abstract
Dengue infections are still a worldwide burden, especially in Indonesia. There is no specific medication against the dengue virus. Recently, many types of research have been conducted to discover a new drug for dengue virus using natural resource extracts. Indonesia, as a tropical [...] Read more.
Dengue infections are still a worldwide burden, especially in Indonesia. There is no specific medication against the dengue virus. Recently, many types of research have been conducted to discover a new drug for dengue virus using natural resource extracts. Indonesia, as a tropical country, has a wide biodiversity. There are several medicinal plants in Indonesia that are believed to possess anti-dengue activity, such as Myristica fatua, Cymbopogon citratus, and Acorus calamus plants. We conducted an in vitro laboratory experiment of several extracts from Indonesian herbs combined with in silico analysis. The extracts were evaluated for safety and antiviral activity in Huh7it-1 cell lines, using a single dose of 20 µg/mL and dose-dependent (5, 10, 20, 40, 80 and 160 µg/mL) of plant extracts against dengue virus serotype 2 (DENV-2) NGC strain. The DMSO 0.1% was used as a negative control. The cytotoxic aspect was assessed by counting the cell viability, while the antiviral activity was calculated by counting the average inhibition. The selectivity index (SI) of plant extracts were performed from a ratio of CC50/EC50 value. In silico analysis was conducted to determine the free energy of binding between NS5 of dengue virus with bioactive compounds contained in Myristica fatua, Cymbopogon citratus and Acorus calamus extract plants. We determined that all extracts were not toxic against Huh7it-1 cell lines. The methanolic extracts of A. calamus, C. citratus, and M. fatua showed inhibition of DENV-2 at a dose of 20 µg/mL to 96.5%, 98.9%, and 122.7%, respectively. The dose-dependent effects showed that M. fatua has the best inhibition activity towards DENV-2. Molecular docking result showed that artesunic acid within M. fatua has the best free energy of binding (−7.2 kcal/mol), followed by homoegonol (−7.1 kcal/mol) which was slightly different from artesunic acid among others. The methanolic extracts of A. calamus, C. citratus, and M. fatua showed prospective anti-dengue activities both in vitro and in silico. Future research should be conducted to find the pure extracts of all useful herbs as a new candidate of antiviral drug. Full article
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Open AccessArticle
Experimental Infection of Human Volunteers with the Heat-Stable Enterotoxin-Producing Enterotoxigenic Escherichia coli Strain TW11681
Received: 24 May 2019 / Revised: 17 June 2019 / Accepted: 20 June 2019 / Published: 22 June 2019
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Abstract
Infection with enterotoxigenic Escherichia coli (ETEC) producing the heat-stable enterotoxin (ST) is one of the most important causes of childhood diarrhoea in low- and middle-income countries. Here, we undertook a controlled human infection model (CHIM) study to investigate whether ST-producing ETEC strain TW11681 [...] Read more.
Infection with enterotoxigenic Escherichia coli (ETEC) producing the heat-stable enterotoxin (ST) is one of the most important causes of childhood diarrhoea in low- and middle-income countries. Here, we undertook a controlled human infection model (CHIM) study to investigate whether ST-producing ETEC strain TW11681 would be suitable for testing the protective efficacy of new ST-based vaccine candidates in vaccine challenge models. In groups of three, nine volunteers ingested 1 × 106, 1 × 107, or 1 × 108 colony-forming units (CFU) of TW11681. Flow cytometry-based assays were used to measure CD4+ T cell responses and antibody levels targeting virulence factors expressed by the strain. We found that infection with TW11681 elicited few and mild symptoms, including mild diarrhoea in two volunteers, both of whom ingested 1 × 106 CFU. Averaged across all volunteers, the CD4+ T cell responses specific for E. coli YghJ mucinase peaked 10 days after infection (3.2-fold (p = 0.016)), while the CD4+ T cell responses specific for Colonization Factor Antigen I (CFA/I) major fimbrial subunit (CfaB) peaked after 28 days (3.6-fold (p = 0.063)). The serum CfaB-specific anti-IgA and anti-IgG/IgM levels were significantly increased and peaked 3 months after infection. Both remained elevated for the duration of the 12-month follow-up. The corresponding anti-YghJ serological response was strongest after 10 days, although a significant increase was seen only for IgA levels (3.2-fold (p = 0.008)). In conclusion, due to its low diarrhoea attack risk, TW11681 is probably not suitable for testing the efficacy of new vaccines in human challenge studies at doses 1 × 106 to 1 × 108. However, the strain may still be useful in CHIMs for studying ETEC host-pathogen interactions. Full article
(This article belongs to the Section Vaccines and Therapeutic Developments)
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Open AccessReview
How Many Mammalian Reovirus Proteins are involved in the Control of the Interferon Response?
Received: 31 May 2019 / Revised: 17 June 2019 / Accepted: 18 June 2019 / Published: 21 June 2019
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Abstract
As with most viruses, mammalian reovirus can be recognized and attacked by the host-cell interferon response network. Similarly, many viruses have developed resistance mechanisms to counteract the host-cell response at different points of this response. Reflecting the complexity of the interferon signaling pathways [...] Read more.
As with most viruses, mammalian reovirus can be recognized and attacked by the host-cell interferon response network. Similarly, many viruses have developed resistance mechanisms to counteract the host-cell response at different points of this response. Reflecting the complexity of the interferon signaling pathways as well as the resulting antiviral response, viruses can—and often have—evolved many determinants to interfere with this innate immune response and allow viral replication. In the last few years, it has been evidenced that mammalian reovirus encodes many different determinants that are involved in regulating the induction of the interferon response or in interfering with the action of interferon-stimulated gene products. In this brief review, we present our current understanding of the different reovirus proteins known to be involved, introduce their postulated modes of action, and raise current questions that may lead to further investigations. Full article
(This article belongs to the Special Issue Reoviruses and the Interferon Response)
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Open AccessArticle
Host-Pathogen Interactions of Mycoplasma mycoides in Caprine and Bovine Precision-Cut Lung Slices (PCLS) Models
Received: 29 May 2019 / Revised: 13 June 2019 / Accepted: 18 June 2019 / Published: 20 June 2019
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Abstract
Respiratory infections caused by mycoplasma species in ruminants lead to considerable economic losses. Two important ruminant pathogens are Mycoplasma mycoides subsp. Mycoides (Mmm), the aetiological agent of contagious bovine pleuropneumonia and Mycoplasma mycoides subsp. capri (Mmc), which causes pneumonia, [...] Read more.
Respiratory infections caused by mycoplasma species in ruminants lead to considerable economic losses. Two important ruminant pathogens are Mycoplasma mycoides subsp. Mycoides (Mmm), the aetiological agent of contagious bovine pleuropneumonia and Mycoplasma mycoides subsp. capri (Mmc), which causes pneumonia, mastitis, arthritis, keratitis, and septicemia in goats. We established precision cut lung slices (PCLS) infection model for Mmm and Mmc to study host-pathogen interactions. We monitored infection over time using immunohistological analysis and electron microscopy. Moreover, infection burden was monitored by plating and quantitative real-time PCR. Results were compared with lungs from experimentally infected goats and cattle. Lungs from healthy goats and cattle were also included as controls. PCLS remained viable for up to two weeks. Both subspecies adhered to ciliated cells. However, the titer of Mmm in caprine PCLS decreased over time, indicating species specificity of Mmm. Mmc showed higher tropism to sub-bronchiolar tissue in caprine PCLS, which increased in a time-dependent manner. Moreover, Mmc was abundantly observed on pulmonary endothelial cells, indicating partially, how it causes systemic disease. Tissue destruction upon prolonged infection of slices was comparable to the in vivo samples. Therefore, PCLS represents a novel ex vivo model to study host-pathogen interaction in livestock mycoplasma. Full article
(This article belongs to the Section Animal Pathogens)
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Open AccessArticle
Detection of Pathogenic Viruses, Pathogen Indicators, and Fecal-Source Markers within Tanker Water and Their Sources in the Kathmandu Valley, Nepal
Received: 21 May 2019 / Revised: 12 June 2019 / Accepted: 17 June 2019 / Published: 19 June 2019
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Abstract
Tanker water is used extensively for drinking as well as domestic purposes in the Kathmandu Valley of Nepal. This study aimed to investigate water quality in terms of microbial contamination and determine sources of fecal pollution within these waters. Thirty-one samples from 17 [...] Read more.
Tanker water is used extensively for drinking as well as domestic purposes in the Kathmandu Valley of Nepal. This study aimed to investigate water quality in terms of microbial contamination and determine sources of fecal pollution within these waters. Thirty-one samples from 17 tanker filling stations (TFSs) and 30 water tanker (WT) samples were collected during the dry and wet seasons of 2016. Escherichia coli was detected in 52% of the 31 TFS samples and even more frequently in WT samples. Of the six pathogenic viruses tested, enteroviruses, noroviruses of genogroup II (NoVs-GII), human adenoviruses (HAdVs), and group A rotaviruses were detected using quantitative PCR (qPCR) at 10, five, four, and two TFSs, respectively, whereas Aichi virus 1 and NoVs-GI were not detected at any sites. Index viruses, such as pepper mild mottle virus and tobacco mosaic virus, were detected using qPCR in 77% and 95% out of 22 samples, respectively, all of which were positive for at least one of the tested pathogenic viruses. At least one of the four human-associated markers tested (i.e., BacHum, HAdVs, and JC and BK polyomaviruses) was detected using qPCR in 39% of TFS samples. Ruminant-associated markers were detected at three stations, and pig- and chicken-associated markers were found at one station each of the suburbs. These findings indicate that water supplied by TFSs is generally of poor quality and should be improved, and proper management of WTs should be implemented. Full article
(This article belongs to the Special Issue Enteric Viruses in Aquatic Environments)
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Open AccessArticle
Evolutionary Dynamics in the RNA Bacteriophage Qβ Depends on the Pattern of Change in Selective Pressures
Received: 22 May 2019 / Revised: 14 June 2019 / Accepted: 16 June 2019 / Published: 18 June 2019
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Abstract
The rate of change in selective pressures is one of the main factors that determines the likelihood that populations can adapt to stress conditions. Generally, the reduction in the population size that accompanies abrupt environmental changes makes it difficult to generate and select [...] Read more.
The rate of change in selective pressures is one of the main factors that determines the likelihood that populations can adapt to stress conditions. Generally, the reduction in the population size that accompanies abrupt environmental changes makes it difficult to generate and select adaptive mutations. However, in systems with high genetic diversity, as happens in RNA viruses, mutations with beneficial effects under new conditions can already be present in the population, facilitating adaptation. In this work, we have propagated an RNA bacteriophage (Qβ) at temperatures higher than the optimum, following different patterns of change. We have determined the fitness values and the consensus sequences of all lineages throughout the evolutionary process in order to establish correspondences between fitness variations and adaptive pathways. Our results show that populations subjected to a sudden temperature change gain fitness and fix mutations faster than those subjected to gradual changes, differing also in the particular selected mutations. The life-history of populations prior to the environmental change has great importance in the dynamics of adaptation. The conclusion is that in the bacteriophage Qβ, the standing genetic diversity together with the rate of temperature change determine both the rapidity of adaptation and the followed evolutionary pathways. Full article
(This article belongs to the Special Issue Modeling Virus Dynamics and Evolution)
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Open AccessArticle
Isolation and Molecular Identification of Virulence, Antimicrobial and Heavy Metal Resistance Genes in Livestock-Associated Methicillin-Resistant Staphylococcus aureus
Received: 23 April 2019 / Revised: 16 May 2019 / Accepted: 16 May 2019 / Published: 14 June 2019
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Abstract
Staphylococcus aureus is one of the most important pathogens of humans and animals. Livestock production contributes a significant proportion to the South African Gross Domestic Product. Consequently, the aim of this study was to determine for the first time the prevalence, virulence, antibiotic [...] Read more.
Staphylococcus aureus is one of the most important pathogens of humans and animals. Livestock production contributes a significant proportion to the South African Gross Domestic Product. Consequently, the aim of this study was to determine for the first time the prevalence, virulence, antibiotic and heavy metal resistance in livestock-associated S. aureus isolated from South African livestock production systems. Microbial phenotypic methods were used to detect the presence of antibiotic and heavy metal resistance. Furthermore, molecular DNA based methods were used to genetically determine virulence as well as antibiotic and heavy metal resistance determinants. Polymerase chain reaction (PCR) confirmed 217 out of 403 (53.8%) isolates to be S. aureus. Kirby-Bauer disc diffusion method was conducted to evaluate antibiotic resistance and 90.8% of S. aureus isolates were found to be resistant to at least three antibiotics, and therefore, classified as multidrug resistant. Of the antibiotics tested, 98% of the isolates demonstrated resistance towards penicillin G. High resistance was shown against different heavy metals, with 90% (196/217), 88% (192/217), 86% (188/217) and 84% (183/217) of the isolates resistant to 1500 µg/mL concentration of Cadmium (Cd), Zinc (Zn), Lead (Pb) and Copper (Cu) respectively. A total of 10 antimicrobial resistance and virulence genetic determinants were screened for all livestock associated S. aureus isolates. Methicillin-resistant S. aureus (MRSA) isolates were identified, by the presence of mecC, in 27% of the isolates with a significant relationship (p < 0.001)) with the host animal. This is the first report of mecC positive LA-MRSA in South Africa and the African continent. The gene for tetracycline resistance (tetK) was the most frequently detected of the screened genes with an overall prevalence of 35% and the highest prevalence percentage was observed for goats (56.76%) followed by avian species (chicken, duck and wild birds) (42.5%). Virulence-associated genes were observed across all animal host species. The study reports the presence of luks/pv, a gene encoding the PVL toxin previously described to be a marker for community acquired-MRSA, suggesting the crossing of species between human and livestock. The high prevalence of S. aureus from the livestock indicates a major food security and healthcare threat. This threat is further compounded by the virulence of the pathogen, which causes numerous clinical manifestations. The phenomenon of co-selection is observed in this study as isolates exhibited resistance to both antibiotics and heavy metals. Further, all the screened antibiotic and heavy metal resistance genes did not correspond with the phenotypic resistance. Full article
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Open AccessReview
Biocontrol of Cereal Crop Diseases Using Streptomycetes
Received: 14 May 2019 / Revised: 5 June 2019 / Accepted: 9 June 2019 / Published: 13 June 2019
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Abstract
A growing world population and an increasing demand for greater food production requires that crop losses caused by pests and diseases are dramatically reduced. Concurrently, sustainability targets mean that alternatives to chemical pesticides are becoming increasingly desirable. Bacteria in the plant root microbiome [...] Read more.
A growing world population and an increasing demand for greater food production requires that crop losses caused by pests and diseases are dramatically reduced. Concurrently, sustainability targets mean that alternatives to chemical pesticides are becoming increasingly desirable. Bacteria in the plant root microbiome can protect their plant host against pests and pathogenic infection. In particular, Streptomyces species are well-known to produce a range of secondary metabolites that can inhibit the growth of phytopathogens. Streptomyces are abundant in soils and are also enriched in the root microbiomes of many different plant species, including those grown as economically and nutritionally valuable cereal crops. In this review we discuss the potential of Streptomyces to protect against some of the most damaging cereal crop diseases, particularly those caused by fungal pathogens. We also explore factors that may improve the efficacy of these strains as biocontrol agents in situ, as well as the possibility of exploiting plant mechanisms, such as root exudation, that enable the recruitment of microbial species from the soil to the root microbiome. We argue that a greater understanding of these mechanisms may enable the development of protective plant root microbiomes with a greater abundance of beneficial bacteria, such as Streptomyces species. Full article
(This article belongs to the Special Issue Streptomyces Microbiomes in Agriculture)
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Open AccessReview
The Mosquito Immune System and the Life of Dengue Virus: What We Know and Do Not Know
Received: 4 April 2019 / Revised: 29 May 2019 / Accepted: 30 May 2019 / Published: 13 June 2019
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Abstract
Flaviviruses are largely transmitted to humans by their arthropod vectors such as mosquitoes or ticks. The dengue virus (DENV) is one of the members of the family Flaviviridae and is the causative agent of dengue fever. In the mosquito vector, DENV enters through [...] Read more.
Flaviviruses are largely transmitted to humans by their arthropod vectors such as mosquitoes or ticks. The dengue virus (DENV) is one of the members of the family Flaviviridae and is the causative agent of dengue fever. In the mosquito vector, DENV enters through viremic blood meal and replicates in the mid-gut. Newly formed virion particles circulate to various mosquito organs and get transmitted to the next host in subsequent bites. Aedes aegypti and Aedes albopictus have intricate immune control to allow DENV production at a sub-pathogenic level. In the mosquito, antimicrobial peptides (AMP) and RNA inference (RNAi) are the two main antiviral strategies used against DENV. Apart from innate immunity, mosquito resident microbes play a significant role in modulating DENV replication. In this review, we discuss different immune mechanisms and preventive strategies that act against DENV in two of its vectors: Aedes aegypti and Aedes albopictus. Full article
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Open AccessReview
Variable and Variant Protein Multigene Families in Babesia bovis Persistence
Received: 13 May 2019 / Revised: 3 June 2019 / Accepted: 7 June 2019 / Published: 11 June 2019
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Abstract
Cattle infected with Babesia bovis face a bifurcated fate: Either die of the severe acute infection, or survive and carry for many years a highly persistent but generally asymptomatic infection. In this review, the author describes known and potential contributions of three variable [...] Read more.
Cattle infected with Babesia bovis face a bifurcated fate: Either die of the severe acute infection, or survive and carry for many years a highly persistent but generally asymptomatic infection. In this review, the author describes known and potential contributions of three variable or highly variant multigene-encoded families of proteins to persistence in the bovine host, and the mechanisms by which variability arises among these families. Ramifications arising from this variability are discussed. Full article
(This article belongs to the Special Issue Persistence in Babesia)
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Open AccessArticle
Severe Clinical Outcomes of Tuberculosis in Kharkiv Region, Ukraine, Are Associated with Beijing Strains of Mycobacterium tuberculosis
Received: 20 March 2019 / Revised: 2 June 2019 / Accepted: 6 June 2019 / Published: 10 June 2019
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Abstract
Genotypic variation in Beijing lineages of Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB), has been associated with hyper virulence and the spread of extensively and multiple drug (X/MDR) resistant MTB strains in Eastern Europe, Central Asia, and East Asia. The clinical [...] Read more.
Genotypic variation in Beijing lineages of Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB), has been associated with hyper virulence and the spread of extensively and multiple drug (X/MDR) resistant MTB strains in Eastern Europe, Central Asia, and East Asia. The clinical outcomes of 215 new cases of TB among the population of the Kharkiv region of Eastern Ukraine were analyzed to uncover factors associated with severe infection. Infecting MTB strains were profiled by 5 locus exact tandem repeats (ETRs) and 15 locus mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) genotyping. Among diverse MTB genotypes discovered in Ukraine, the Beijing genotype (MIRU-VNTR 42425) was significantly associated with risk factors for severe outcomes of disease in the study population, including TB/HIV co-infection and treatment failure. Strain replacement (superinfection) was observed in 10 patients, suggesting repeated exposure to novel MTB strains in hospital or community settings. Inclusion of MTB genotyping data may identify at-risk patients and improve treatment adherence to prevent X/MDR development for effective public health response against tuberculosis in Ukraine. Full article
(This article belongs to the Section Human Pathogens)
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Open AccessArticle
Replication of Crohn’s Disease Mucosal E. coli Isolates inside Macrophages Correlates with Resistance to Superoxide and Is Dependent on Macrophage NF-kappa B Activation
Received: 29 March 2019 / Revised: 2 June 2019 / Accepted: 6 June 2019 / Published: 8 June 2019
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Abstract
Mucosa-associated Escherichia coli are increased in Crohn’s disease (CD) and colorectal cancer (CRC). CD isolates replicate within macrophages but the specificity of this effect for CD and its mechanism are unclear. Gentamicin exclusion assay was used to assess E. coli replication within J774.A1 [...] Read more.
Mucosa-associated Escherichia coli are increased in Crohn’s disease (CD) and colorectal cancer (CRC). CD isolates replicate within macrophages but the specificity of this effect for CD and its mechanism are unclear. Gentamicin exclusion assay was used to assess E. coli replication within J774.A1 murine macrophages. E. coli growth was assessed following acid, low-nutrient, nitrosative, oxidative and superoxide stress, mimicking the phagolysosome. Twelve of 16 CD E. coli isolates replicated >2-fold within J774.A1 macrophages; likewise for isolates from 6/7 urinary tract infection (UTI), 8/9 from healthy subjects, compared with 2/6 ulcerative colitis, 2/7 colorectal cancer and 0/3 laboratory strains. CD mucosal E. coli were tolerant of acidic, low-nutrient, nitrosative and oxidative stress. Replication within macrophages correlated strongly with tolerance to superoxide stress (rho = 0.44, p = 0.0009). Exemplar CD E. coli HM605 and LF82 were unable to survive within Nfκb1-/- murine bone marrow-derived macrophages. In keeping with this, pre-incubation of macrophages with hydrocortisone (0.6 µM for 24 h) caused 70.49 ± 12.11% inhibition of intra-macrophage replication. Thus, CD mucosal E. coli commonly replicate inside macrophages, but so do some UTI and healthy subject strains. Replication correlates with resistance to superoxide and is highly dependent on macrophage NF-κB signalling. This may therefore be a good therapeutic target. Full article
(This article belongs to the Section Human Pathogens)
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Open AccessArticle
Characterization of Biological Resistance and Successful Drug Resistance Control in Medicine
Received: 16 May 2019 / Revised: 24 May 2019 / Accepted: 27 May 2019 / Published: 31 May 2019
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Abstract
It has now been a century that drug resistance has been getting worse in human infectious diseases medicine. A similar trend is observed in veterinary medicine and agriculture. The successful control of drug resistance requires an understanding of biological resistance in general, as [...] Read more.
It has now been a century that drug resistance has been getting worse in human infectious diseases medicine. A similar trend is observed in veterinary medicine and agriculture. The successful control of drug resistance requires an understanding of biological resistance in general, as a phenomenon taking place in nature. Once we have understood the main characteristics of biological resistance and how it operates in nature, we can then apply that new understanding to its subset that drug resistance in human medicine is. Possession of such an edge can also lead to the successful control of resistance in veterinary medicine, in agriculture, and in other settings of resistance activity by biological organisms. Based on biological resistance data from human medicine, veterinary medicine, and agriculture, some of the fundamental characteristics of resistance as a natural process displayed by all living organisms are established. The consistent, common features characterizing the data are exploited, as is a mathematical model depicting how biological resistance strengthens in living organisms. It is found that biological resistance in general, and drug resistance in particular, is a phenomenon governed by at least two laws: the First Law of Resistance, requiring a threshold to be met before resistance can be prevented and the Second Law of Resistance, causing resistance to strengthen to infinite levels if unstopped. Inference is thereafter made as to the drug design strategy required for the successful control of resistance in medicine. To that end, the blueprint currently applied in the design of infectious diseases drugs needs revising. Full article
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Open AccessArticle
Animal Virus Ecology and Evolution Are Shaped by the Virus Host-Body Infiltration and Colonization Pattern
Received: 20 March 2019 / Revised: 19 April 2019 / Accepted: 20 May 2019 / Published: 25 May 2019
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Abstract
The current classification of animal viruses is largely based on the virus molecular world. Less attention is given to why and how virus fitness results from the success of virus transmission. Virus transmission reflects the infection-shedding-transmission dynamics, and with it, the organ system [...] Read more.
The current classification of animal viruses is largely based on the virus molecular world. Less attention is given to why and how virus fitness results from the success of virus transmission. Virus transmission reflects the infection-shedding-transmission dynamics, and with it, the organ system involvement and other, macroscopic dimensions of the host environment. This study describes the transmission ecology of the world main livestock viruses, 36 in total, a mix of RNA, DNA and retroviruses. Following an iterative process, the viruses are virtually ranked in an outer- to inner-body fashion, by organ system, on ecological grounds. Also portrayed are the shifts in virus host tropism and virus genome. The synthesis of the findings reveals a predictive virus evolution framework, based on the outer- to inner-body changes in the interplay of host environment-transmission modes-organ system involvement-host cell infection cycle-virus genome. Outer-body viruses opportunistically respond to the variation in the external environment. For example, respiratory and enteric viruses tend to be associated with poultry and pig mass rearing. Ruminant and equine viruses tend to be more deep-rooted and host-specific, and also establish themselves in the vital inner-body systems. It is concluded that the framework may assist the study of new emerging viruses and pandemic risks. Full article
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Open AccessArticle
Assessment of the Antimicrobial Potentiality and Functionality of Lactobacillus plantarum Strains Isolated from the Conventional Inner Mongolian Fermented Cheese Against Foodborne Pathogens
Received: 17 April 2019 / Revised: 7 May 2019 / Accepted: 13 May 2019 / Published: 21 May 2019
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Abstract
Lactobacillus plantarum are amongst the diversified lactic acid bacteria (LAB) species which are being utilized abundantly in the food industry. Numerous L. plantarum strains have been reported to produce several antimicrobial compounds. Diacetyl, hydrogen peroxide, organic acids, as well as bacteriocins can also [...] Read more.
Lactobacillus plantarum are amongst the diversified lactic acid bacteria (LAB) species which are being utilized abundantly in the food industry. Numerous L. plantarum strains have been reported to produce several antimicrobial compounds. Diacetyl, hydrogen peroxide, organic acids, as well as bacteriocins can also be exemplified by a variable spectrum of actions. The current study was intended to conduct the screening and characterization of antimicrobial prospective of L. plantarum from traditional Inner Mongolian fermented hard cheese. Foodborne pathogens, Salmonella typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus, were examined by using the Oxford cup technique and the mixed culture inhibition assays. The resulting analyses disclosed that L. plantarum KLDS1.0344 indicated broad antimicrobial spectrum against all selected pathogens as compared to other LAB used in this study. Additionally, the decrement of the pathogen population was observed up to 3.47 logs in mixed culture inhibition assays. L. plantarum KLDS 1.0344 acid production was recorded up to 71.8 ± 3.59 °D in mixed culture while antimicrobial particles released in cell free supernatants demonstrated bacteriocin-like characteristics showing substantial pH stability (2.0–6.0), proteolytic enzyme reduced the antibacterial activity (15.2 ± 0.6 mm–20.4 ± 0.8 mm), heat stability (20 min at 120 °C) against selected pathogens. Moreover, the spectrum range of antimicrobial peptides after the partial purification was decreased as compared to the crude bacteriocin-like compound. The SDS-PAGE analysis showed the molecular weight range of partially purified bacteriocin from 12 to 45 kDa. After analyzing the obtained data from the current experimentation showed that the capability of L. plantarum KLDS 1.0344 to oppose the pathogen growth in vitro relies on the occurrence of organic acids along with bacteriocin-like compounds proving L. plantarum KLDS 1.0344 as a potentially appropriate candidate as an alternative bio-control agent against foodborne pathogens. Full article
(This article belongs to the Section Waterborne/Foodborne/Airborne Pathogens)
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Open AccessReview
Fungal-Bacterial Interactions in Health and Disease
Received: 22 February 2019 / Revised: 2 May 2019 / Accepted: 16 May 2019 / Published: 21 May 2019
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Abstract
Fungi and bacteria encounter each other in various niches of the human body. There, they interact directly with one another or indirectly via the host response. In both cases, interactions can affect host health and disease. In the present review, we summarized current [...] Read more.
Fungi and bacteria encounter each other in various niches of the human body. There, they interact directly with one another or indirectly via the host response. In both cases, interactions can affect host health and disease. In the present review, we summarized current knowledge on fungal-bacterial interactions during their commensal and pathogenic lifestyle. We focus on distinct mucosal niches: the oral cavity, lung, gut, and vagina. In addition, we describe interactions during bloodstream and wound infections and the possible consequences for the human host. Full article
(This article belongs to the Special Issue Immunology of Fungal Infections)
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Open AccessArticle
Infections with Carbapenem-Resistant Gram-Negative Bacteria are a Serious Problem Among Critically Ill Children: A Single-Centre Retrospective Study
Received: 23 April 2019 / Revised: 16 May 2019 / Accepted: 20 May 2019 / Published: 21 May 2019
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Abstract
Children in paediatric intensive care units (PICUs) are vulnerable to infections because invasive devices are frequently used during their admission. We aimed to determine the prevalence, associated factors, and prognosis of infections in our PICU. This retrospective study evaluated culture results from 477 [...] Read more.
Children in paediatric intensive care units (PICUs) are vulnerable to infections because invasive devices are frequently used during their admission. We aimed to determine the prevalence, associated factors, and prognosis of infections in our PICU. This retrospective study evaluated culture results from 477 paediatric patients who were treated in the PICU between January 2014 and March 2019. Ninety patients (18.9%) had bacterial infections, with gram-negative bacteria being the predominant infectious agents. Culture-positive patients were younger than culture-negative patients, and age was related to mortality and various clinical factors. Culture-positive bacterial infections in the PICU were associated with increased use of invasive mechanical ventilation (odds ratio(OR); 2.254), red blood cell (RBC) transfusions (OR:2.624), and inotropic drugs (OR:2.262). Carbapenem resistance was found in approximately one-third of gram-negative bacteria, and was most common in tracheal aspirate specimens and cases involving Klebsiella spp. Total parenteral nutrition was a significant risk factor (OR:5.870). Positive blood culture results were associated with poorer patient survival than other culture results. These findings indicate that infections, especially those involving carbapenem-resistant bacteria, are an important issue when treating critically ill children. Full article
(This article belongs to the Section Human Pathogens)
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Open AccessArticle
Demographics and Epidemiology of Hepatitis B in the State of Qatar: A Five-Year Surveillance-Based Incidence Study
Received: 5 April 2019 / Revised: 9 May 2019 / Accepted: 18 May 2019 / Published: 21 May 2019
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Abstract
Background: Expatriates represent >80% of Qatar’s population, mostly arriving from countries in Africa and Asia that are endemic with many diseases. This increases the risk for introducing new pathogens into the country and provides a platform for maintenance of endemic pathogen circulation. [...] Read more.
Background: Expatriates represent >80% of Qatar’s population, mostly arriving from countries in Africa and Asia that are endemic with many diseases. This increases the risk for introducing new pathogens into the country and provides a platform for maintenance of endemic pathogen circulation. Here, we report on the incidence and epidemiological characteristics of hepatitis B in Qatar between 2010 and 2014. Methods: We performed a retrospective epidemiological data analysis using the data available at the surveillance system of the Ministry of Public Health (MOPH) in Qatar. Data were collected from distinctive public and private incorporates around the nation. Reported cases of hepatitis B patients represent those who met the stringent case definition as per World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) guidelines and eventually reported to MOPH. Results: The annual incidence rates of hepatitis B cases were 30.0, 34.2, 30.5, 39.4, and 19.8 per 100,000 population in 2010, 2011, 2012, 2013, and 2014, respectively. There was no specific trend or seasonality for the reported cases. The incidence rates were higher in females compared to males between 2010 and 2012, but similar in 2013 and 2014. The highest incidence rates were reported among individuals between 25 and 34 years of age. No cases were reported in children younger than five years in 2013 and 2014. Rates of hepatitis B cases declined dramatically in 2014, in both Qataris and non-Qataris, as compared to the previous years. Conclusion: Our results indicate a dramatic decline of hepatitis B cases in Qatar but mandate improved surveillance and vaccination efforts in expatriates in the nation. Full article
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Open AccessReview
A Contemporary View of Respiratory Syncytial Virus (RSV) Biology and Strain-Specific Differences
Received: 28 March 2019 / Revised: 1 May 2019 / Accepted: 4 May 2019 / Published: 21 May 2019
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Abstract
Respiratory syncytial virus (RSV) is a human respiratory pathogen which remains a leading viral cause of hospitalizations and mortality among infants in their first year of life. Here, we review the biology of RSV, the primary laboratory isolates or strains which have been [...] Read more.
Respiratory syncytial virus (RSV) is a human respiratory pathogen which remains a leading viral cause of hospitalizations and mortality among infants in their first year of life. Here, we review the biology of RSV, the primary laboratory isolates or strains which have been used to best characterize the virus since its discovery in 1956, and discuss the implications for genetic and functional variations between the established laboratory strains and the recently identified clinical isolates. Full article
(This article belongs to the Special Issue Virus-Host Interactions of Respiratory Syncytial Virus (RSV))
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Open AccessArticle
Occurrence of Bovine Cysticercosis in Two Regions of the State of Tocantins-Brazil and the Importance of Pathogen Identification
Received: 11 April 2019 / Revised: 13 May 2019 / Accepted: 16 May 2019 / Published: 20 May 2019
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Abstract
Bovine cysticercosis, caused by Taenia saginata metacestodes, is the cause of significant economic losses to the meat production chain by condemnation and downgrading of infected carcasses. It is also a public health issue causing human taeniasis. This study evaluated the occurrence of bovine [...] Read more.
Bovine cysticercosis, caused by Taenia saginata metacestodes, is the cause of significant economic losses to the meat production chain by condemnation and downgrading of infected carcasses. It is also a public health issue causing human taeniasis. This study evaluated the occurrence of bovine cysticercosis at the meat inspection procedures in slaughterhouses of south and north regions of the Tocantins State in Brazil. Specimens identified as cysts of T. saginata were collected and analyzed by molecular (PCR) and histopathological techniques. The cysts were collected from March to December of 2010 in slaughterhouses located in the cities of Alvorada (South) and Araguaína (North). The frequency of cystic lesions during the study was 0.033% (53/164,091) with 69.81% of calcified lesions and 30.9% of live cysts at meat inspection. From 14 samples submitted to molecular analysis, 28.57% (4/14) were positive for T. saginata. The histopathological analysis of the non-T. saginata samples showed lesions suggestive of granuloma and hydatid disease. The results indicated that the identification of the etiological agent is difficult by macroscopic inspection, emphasizing the need to associate specific diagnostic methods at meat inspection in abattoirs. In addition, species-specific PCR would be an effective tool for diagnosis, monitoring, and identifying cysticercosis, assisting the conventional tests. Full article
(This article belongs to the Special Issue Zoonotic Diseases and One Health)
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Open AccessArticle
Differential Helicobacter pylori Plasticity in the Gastric Niche of Subjects at Increased Gastric Cancer Risk
Received: 8 March 2019 / Revised: 9 May 2019 / Accepted: 15 May 2019 / Published: 18 May 2019
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Abstract
Helicobacter pylori (H. pylori) represents an independent risk factor for Gastric Cancer (GC). First Degree Relatives (FDR) of GC subjects and Autoimmune Gastritis (AG) patients are both at increased risk for GC. H. pylori genetic heterogeneity within the gastric niche of [...] Read more.
Helicobacter pylori (H. pylori) represents an independent risk factor for Gastric Cancer (GC). First Degree Relatives (FDR) of GC subjects and Autoimmune Gastritis (AG) patients are both at increased risk for GC. H. pylori genetic heterogeneity within the gastric niche of FDR and AG individuals has been little explored. To understand whether they exploit an increased H. pylori stability and virulence, 14 AG, 25 FDR, 39 GC and 13 dyspeptic patients (D) were investigated by a cultural PCR-based approach characterizing single colonies-forming-units. We chose three loci within the Cytotoxin-associated gene-A Pathogenicity Island (CagPAI) (cagA,cagE,virB11), vacA, homA and homB as markers of virulence with reported association to GC. Inflammatory/precancerous lesions were staged according to Sydney System. When compared to D, FDR, similarly to GC patients, were associated to higher atrophy (OR = 6.29; 95% CI:1.23–31.96 in FDR; OR = 7.50; 95% CI:1.67–33.72 in GC) and a lower frequency of mixed infections (OR = 0.16; 95% CI:0.03–0.81 in FDR; OR = 0.10; 95% CI:0.02–0.48 in GC). FDR presented also an increased neutrophil infiltration (OR = 7.19; 95% CI:1.16–44.65). Both FDR and GC carried a higher proportion of CagPAI+vacAs1i1mx+homB+ profiles (OR = 2.71; 95% CI: 1.66–4.41 and OR = 3.43; 95% CI: 2.16–5.44, respectively). Conversely, AG patients presented a lower frequency of subtypes carrying a stable CagPAI and vacAs1i1mx. These results underline different H. pylori plasticity in FDR and AG individuals, and thus, a different host-bacterium interaction capacity that should be considered in the context of eradication therapies. Full article
(This article belongs to the Section Human Pathogens)
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Open AccessArticle
Piper betel Compounds Piperidine, Eugenyl Acetate, and Chlorogenic Acid Are Broad-Spectrum Anti-Vibrio Compounds that Are Also Effective on MDR Strains of the Pathogen
Received: 17 March 2019 / Revised: 30 April 2019 / Accepted: 7 May 2019 / Published: 13 May 2019
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Abstract
The natural population of the aquatic environment supports a diverse aquatic biota and a robust seafood industry. However, this environment also provides an appropriate niche for the growth of pathogenic bacteria that cause problems for human health. For example, species of the genus [...] Read more.
The natural population of the aquatic environment supports a diverse aquatic biota and a robust seafood industry. However, this environment also provides an appropriate niche for the growth of pathogenic bacteria that cause problems for human health. For example, species of the genus Vibrio inhabit marine and estuarine environments. This genus includes species that are pathogenic to aquaculture, invertebrates, and humans. In humans, they can cause prominent diseases like gastroenteritis, wound infections, and septicemia. The increased number of multidrug resistant (MDR) Vibrio strains has drawn the attention of the scientific community to develop new broad-spectrum antibiotics. Hence, in this paper we report the bactericidal effects of compounds derived from Piper betel plants: piperidine, chlorogenic acid, and eugenyl acetate, against various strains of Vibrio species. The different MIC90 values were approximately in a range of 2–6 mg/mL, 5–16 mg/mL, 5–20 mg/mL, and 30–80 mg/mL, for piperidine, chlorogenic acid, and eugenyl acetate, respectively. Piperidine showed the best anti-Vibrio effect against the five Vibrio species tested. Interestingly, combinations of sub-inhibitory concentrations of piperidine, chlorogenic acid, and eugenyl acetate showed inhibitory effects in the Vibrio strains. Furthermore, these compounds showed synergism or partial synergism effects against MDR strains of the Vibrio species when they were incubated with antibiotics (ampicillin and chloramphenicol). Full article
(This article belongs to the Section Vaccines and Therapeutic Developments)
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Open AccessReview
Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update
Received: 30 March 2019 / Revised: 18 April 2019 / Accepted: 8 May 2019 / Published: 11 May 2019
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Abstract
Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 [...] Read more.
Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host–pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas. Full article
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Open AccessArticle
Whole Genome Sequencing of the First H3N8 Equine Influenza Virus Identified in Malaysia
Received: 18 April 2019 / Revised: 7 May 2019 / Accepted: 8 May 2019 / Published: 10 May 2019
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Abstract
In August 2015, Malaysia experienced an outbreak of acute respiratory disease in racehorses. Clinical signs observed were consistent with equine influenza (EI) infection. The index cases were horses recently imported from New Zealand. Rapid control measures, including temporary cancellation of racing, were implemented [...] Read more.
In August 2015, Malaysia experienced an outbreak of acute respiratory disease in racehorses. Clinical signs observed were consistent with equine influenza (EI) infection. The index cases were horses recently imported from New Zealand. Rapid control measures, including temporary cancellation of racing, were implemented to minimize the impact of the outbreak. By November, the disease outbreak was resolved, and movement restrictions were lifted. The aim of this study was to confirm the clinical diagnosis and characterize the causal virus. A pan-reactive influenza type A real-time RT-PCR was used for confirmatory diagnosis. Antigenic characterization by haemagglutinin inhibition using a panel of specific ferret antisera indicated that the causal virus belonged to clade 1 of the H3N8 Florida sub-lineage. The genetic characterization was achieved by the whole genome sequencing of positive nasal swabs from clinically affected animals. Pylogenetic analysis of the haemagglutinin (HA) and neuraminidase (NA) genes demonstrated ≥99% homology with several EI strains that had recently circulated in the USA and Japan. The antigenic and genetic characterization did not indicate that the current World Organisation for Animal Health (OIE) recommendations for EI vaccine composition required modification. Full article
(This article belongs to the Section Animal Pathogens)
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Open AccessArticle
The Mechanism of Action of Ursolic Acid as a Potential Anti-Toxoplasmosis Agent, and Its Immunomodulatory Effects
Received: 30 March 2019 / Revised: 23 April 2019 / Accepted: 25 April 2019 / Published: 9 May 2019
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Abstract
This study was performed to investigate the mechanism of action of ursolic acid in terms of anti-Toxoplasma gondii effects, including immunomodulatory effects. We evaluated the anti-T. gondii effects of ursolic acid, and analyzed the production of nitric oxide (NO), reactive oxygen [...] Read more.
This study was performed to investigate the mechanism of action of ursolic acid in terms of anti-Toxoplasma gondii effects, including immunomodulatory effects. We evaluated the anti-T. gondii effects of ursolic acid, and analyzed the production of nitric oxide (NO), reactive oxygen species (ROS), and cytokines through co-cultured immune cells, as well as the expression of intracellular organelles of T. gondii. The subcellular organelles and granules of T. gondii, particularly rhoptry protein 18, microneme protein 8, and inner membrane complex sub-compartment protein 3, were markedly decreased when T. gondii was treated with ursolic acid, and their expressions were effectively inhibited. Furthermore, ursolic acid effectively increased the production of NO, ROS, interleukin (IL)-10, IL-12, granulocyte macrophage colony stimulating factor (GM-CSF), and interferon-β, while reducing the expression of IL-1β, IL-6, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta 1 (TGF-β1) in T. gondii-infected immune cells. These results demonstrate that ursolic acid not only causes anti-T. gondii activity/action by effectively inhibiting the survival of T. gondii and the subcellular organelles of T. gondii, but also induces specific immunomodulatory effects in T. gondii-infected immune cells. Therefore, this study indicates that ursolic acid can be effectively utilized as a potential candidate agent for developing novel anti-toxoplasmosis drugs, and has immunomodulatory activity. Full article
(This article belongs to the Section Human Pathogens)
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Open AccessReview
Childhood Diarrhoea in the Eastern Mediterranean Region with Special Emphasis on Non-Typhoidal Salmonella at the Human–Food Interface
Received: 12 April 2019 / Revised: 29 April 2019 / Accepted: 1 May 2019 / Published: 6 May 2019
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Abstract
Diarrhoeal disease is still one of the most challenging issues for health in many countries across the Eastern Mediterranean region (EMR), with infectious diarrhoea being an important cause of morbidity and mortality, especially in children under five years of age. However, the understanding [...] Read more.
Diarrhoeal disease is still one of the most challenging issues for health in many countries across the Eastern Mediterranean region (EMR), with infectious diarrhoea being an important cause of morbidity and mortality, especially in children under five years of age. However, the understanding of the aetiological spectrum and the burden of enteric pathogens involved in diarrhoeal disease in the EMR is incomplete. Non-typhoidal Salmonella (NTS), the focus of this review, is one of the most frequently reported bacterial aetiologies in diarrhoeal disease in the EMR. Strains of NTS with resistance to antimicrobial drugs are increasingly reported in both developed and developing countries. In the EMR, it is now widely accepted that many such resistant strains are zoonotic in origin and acquire their resistance in the food-animal host before onward transmission to humans through the food chain. Here, we review epidemiological and microbiological aspects of diarrhoeal diseases among children in the EMR, with emphasis on the implication and burden of NTS. We collate evidence from studies across the EMR on the zoonotic exposure and antimicrobial resistance in NTS at the interface between human and foods of animal origin. This review adds to our understanding of the global epidemiology of Salmonella with emphasis on the current situation in the EMR. Full article
(This article belongs to the Special Issue Zoonotic Diseases and One Health)
Open AccessArticle
Putative Periodontal Pathogens, Filifactor alocis and Peptoanaerobacter stomatis, Induce Differential Cytokine and Chemokine Production by Human Neutrophils
Received: 20 March 2019 / Revised: 17 April 2019 / Accepted: 26 April 2019 / Published: 1 May 2019
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Abstract
Periodontitis is a highly prevalent infectious disease that affects ~ 50% of the adults in the USA alone. Two Gram-positive anaerobic oral bacteria, Filifactor alocis and Peptoanaerobacter stomatis, have emerged as important periodontal pathogens. Neutrophils are a major component of the innate [...] Read more.
Periodontitis is a highly prevalent infectious disease that affects ~ 50% of the adults in the USA alone. Two Gram-positive anaerobic oral bacteria, Filifactor alocis and Peptoanaerobacter stomatis, have emerged as important periodontal pathogens. Neutrophils are a major component of the innate host response in the gingival tissue, and the contribution of neutrophil-derived cytokines and chemokines plays a central role in disease progression. The pattern of cytokines and chemokines released by human neutrophils upon stimulation with newly appreciated periodontal bacteria compared to the keystone oral pathogen Porphyromonas gingivalis was investigated. Our results showed that both F. alocis and P. stomatis triggered TLR2/6 activation. F. alocis induced significant changes in gene expression of cytokines and chemokines in human neutrophils compared to unstimulated cells. However, except for IL-1ra, neutrophils released lower levels of cytokines and chemokines in response to F. alocis compared to P. stomatis. Furthermore, bacteria-free conditioned supernatant collected from neutrophils challenged with P. stomatis, but not from P. gingivalis or F. alocis, was chemotactic towards both neutrophils and monocytes. Elucidating stimuli-specific modulation of human neutrophil effector functions in the context of dysbiotic microbial community constituents provides valuable information for understanding the pathogenesis of periodontal diseases. Full article
(This article belongs to the Section Immunological Responses and Immune Defense Mechanisms)
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Open AccessCommunication
Serological and Molecular Investigation on Toxoplasma gondii Infection in Wild Birds
Received: 12 April 2019 / Revised: 19 April 2019 / Accepted: 24 April 2019 / Published: 29 April 2019
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Abstract
Toxoplasma gondii is an obligate apicomplexan zoonotic parasite that infects humans and other animals and is responsible for toxoplasmosis. This parasite causes one of the most common parasitic infections in humans worldwide. Toxoplasmosis meets the requirements for a One Health Disease due to [...] Read more.
Toxoplasma gondii is an obligate apicomplexan zoonotic parasite that infects humans and other animals and is responsible for toxoplasmosis. This parasite causes one of the most common parasitic infections in humans worldwide. Toxoplasmosis meets the requirements for a One Health Disease due to its ability to affect the health of human beings as well as domestic and free ranging animals. Integrating human, domestic animal, and wildlife data could better assess the risk and devise methods of control. A first step of such an approach would be the knowledge of the prevalence of parasitosis in humans and animals in selected areas. Therefore, the aim of the present study was to evaluate the occurrence of Toxoplasma infection in 216 free ranging birds belonging to different genera/species by serology and molecular techniques. Twenty-five out of 216 animals (11.6%) were positive to the immunofluorescence antibody test (IFAT) with antibody titers ranging from 1/20 to 1/320, and 19 of them (8.8%) also showed a positive PCR for Toxoplasma DNA. The results confirmed the widespread occurrence of Toxoplasma infection in wild birds and serological data were corroborated by molecular results in birds that also had low antibody titers. The knowledge of the wide occurrence of the parasite in game and wild birds should enhance the accurate estimation of the risks in handling, managing, and eating these species with regard to domestic carnivores as well as the impact of viscera and offal in the environment. Full article
(This article belongs to the Special Issue Zoonotic Diseases and One Health)
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