Pathogens

18 pages, 1833 KB

Open AccessArticle

Resequencing and De Novo Assembly of Leishmania (Viannia) guyanensis from Amazon Region: Genome Assessment, Phylogenetic Insights and Therapeutic Targets

by Lucas George Assunção Costa, Edivaldo Costa Sousa Junior, Camila Cristina Cardoso, Millena Arnaud Franco da Igreja, Franklyn Samudio Acosta, Fabiano Reis da Silva and Lourdes Maria Garcez

Pathogens 2026, 15(1), 124; https://doi.org/10.3390/pathogens15010124 - 22 Jan 2026

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Abstract

Leishmania guyanensis is one of 15 American human-pathogenic species, frequently linked to therapeutic failure due to its marked genetic plasticity and adaptability under drug pressure. To broaden the genomic understanding of this species, its biological traits, and potential therapeutic alternatives, we sequenced the [...] Read more.

Leishmania guyanensis is one of 15 American human-pathogenic species, frequently linked to therapeutic failure due to its marked genetic plasticity and adaptability under drug pressure. To broaden the genomic understanding of this species, its biological traits, and potential therapeutic alternatives, we sequenced the L. guyanensis strain MHOM/BR/75/M4147. Raw reads underwent quality-filtering and assembly. Taxonomic classification utilized BLASTn and Kraken2, confirming that 99.95% of contigs matched Leishmania. The assembled genome size was 31 Mb, with an N50 of 4743 bp and 40.85× coverage. Variant calling subsequently identified 36,665 SNPs, 8210 indels, and chromosomal aneuploidies. Genomic annotation identified 3119 proteins with known molecular functions in L. guyanensis, alongside 6371 orthologous genes shared with L. major and L. panamensis. The search for pharmacological relevance yielded ten candidate genes, including one calpain and nine GSK3 family members. Phylogenetic reconstruction using the polA1 gene consistently grouped L. guyanensis, demonstrating strong discriminatory capacity, with L. martiniquensis emerging as the most divergent species. Overall, these findings expand the available genomic framework for L. guyanensis and support advances in species-specific diagnostic approaches. Full article

(This article belongs to the Section Parasitic Pathogens)

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17 pages, 638 KB

Open AccessReview

Plesiomonas shigelloides Bacteremia: A Scoping Review of Epidemiology, Clinical Characteristics, Outcomes, and Implications of Antimicrobial Stewardship

by Nur Izzatul Auni Romli, Salina Mohamed Sukur, Kumutha Malar Vellasamy and Kartini Abdul Jabar

Pathogens 2026, 15(1), 123; https://doi.org/10.3390/pathogens15010123 - 22 Jan 2026

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Abstract

Plesiomonas shigelloides, an aquatic Gram-negative bacillus often associated with self-limiting gastroenteritis, has been reported worldwide. However, to date, no reviews have specifically investigated P. shigelloides bacteremia, which is rare and potentially fatal. This scoping review aimed to examine the existing literature to [...] Read more.

Plesiomonas shigelloides, an aquatic Gram-negative bacillus often associated with self-limiting gastroenteritis, has been reported worldwide. However, to date, no reviews have specifically investigated P. shigelloides bacteremia, which is rare and potentially fatal. This scoping review aimed to examine the existing literature to identify the epidemiology, clinical characteristics, antimicrobial susceptibility, and outcomes of P. shigelloides bacteremia. A PRISMA-ScR-guided search of PubMed, Scopus, Web of Science, and Embase identified 22 published cases, all reported as single-patient case reports. Cases were globally distributed, with the majority reported from the Americas and Europe. The median patient age was 46 years. The case fatality rate was 27.3% (n = 6/22). Most patients had identifiable host risk factors, particularly hematological disorders, neonatal status, or immunocompromised status, and environmental exposure such as raw seafood consumption or contact with freshwater. Clinical presentations were heterogeneous, commonly including fever and sepsis or septic shock. Microbiologically, P. shigelloides demonstrated consistent intrinsic resistance to ampicillin while retaining susceptibility to multiple antimicrobial classes. Poor outcomes were more closely associated with host factors and delayed presentation than with antimicrobial resistance. Early diagnosis, targeted therapy, and antimicrobial stewardship are essential for optimizing outcomes in this rare but severe infection. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in the Post-COVID Era: A Silent Pandemic)

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18 pages, 1430 KB

Open AccessArticle

Extracellular Lipopolysaccharide Triggers the Release of Unconjugated Interferon-Stimulated Gene 15 (ISG15) Protein from Macrophages via Type-I Interferon/Caspase-4/Gasdermin-D Pathway

by Sudiksha Pandit, Lindsay Grace Miller, Indira Mohanty and Santanu Bose

Pathogens 2026, 15(1), 122; https://doi.org/10.3390/pathogens15010122 - 22 Jan 2026

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Abstract

Interferon-stimulated gene 15 (ISG15) is an interferon-induced ubiquitin-like protein that plays an important role in antiviral defense and inflammatory responses, primarily through the process of ISGylation, whereby ISG15 is covalently conjugated to target proteins. Beyond its intracellular functions, a portion of free unconjugated [...] Read more.

Interferon-stimulated gene 15 (ISG15) is an interferon-induced ubiquitin-like protein that plays an important role in antiviral defense and inflammatory responses, primarily through the process of ISGylation, whereby ISG15 is covalently conjugated to target proteins. Beyond its intracellular functions, a portion of free unconjugated ISG15 is also released into the extracellular environment during infections and diseases such as cancer. Extracellular ISG15 is known to regulate immune cell activity and cytokine production. Despite its immune-modulatory role, how ISG15 is released from cells has remained unclear. In this study, we have identified a non-lytic mechanism by which human macrophages release ISG15. Using lipopolysaccharide (LPS) as a stimulus, we show that extracellular LPS triggers unconjugated ISG15 release by utilizing plasma membrane-localized Gasdermin D (GSDMD) pores. Mechanistically, LPS via the autocrine/paracrine action of type-I interferon (IFN) activates caspase-4 (Casp4) to cleave the N-terminal domain of GSDMD for the formation of cell surface GSDMD pores that permit the extracellular release of unconjugated ISG15 in the absence of lytic cell death. Together, our studies have identified the IFN-Casp4-GSDMD axis as a previously unrecognized non-classical pathway for unconjugated ISG15 release from cells. Full article

(This article belongs to the Special Issue Pathogen–Host Interactions: Death, Defense, and Disease)

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15 pages, 4777 KB

Open AccessArticle

Bioinformatics-Driven Systematic Molecular Typing and Rapid qPCR Detection of Escherichia coli Phages: Preliminary Validation with Isolates from Cattle Farms in Xinjiang

by Xinyu Dang, Xiaoguang Cao, Li Li, Lin Yang, Lei Zhao, Jinliang Sheng, Xin Zheng, Chunyan Zhai, Jia Song, Wenhui Wu, Yongjie Wang and Shilei Zhang

Pathogens 2026, 15(1), 121; https://doi.org/10.3390/pathogens15010121 - 22 Jan 2026

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Abstract

This study aimed to classify Escherichia coli phages using bioinformatics analysis systematically and to establish corresponding PCR and qPCR detection methods for rapid molecular typing and identification. Based on 419 complete E. coli phage genomes available in NCBI, phylogenetic and pan-genomic analyses were [...] Read more.

This study aimed to classify Escherichia coli phages using bioinformatics analysis systematically and to establish corresponding PCR and qPCR detection methods for rapid molecular typing and identification. Based on 419 complete E. coli phage genomes available in NCBI, phylogenetic and pan-genomic analyses were conducted to classify the phages at the family, subfamily, and genus levels and to identify highly conserved core genes. Specific primers targeting these core genes were designed, and their specificity, sensitivity, and reproducibility were verified using conventional PCR and dye-based qPCR. A total of 357 phages were successfully classified, encompassing 10 families, 20 subfamilies, and 67 genera. Pan-genomic analysis identified type-specific core genes within 16 taxa, including Ackermannviridae and Demerecviridae, for which 16 pairs of primers were designed. Validation using bacteriophages isolated from Xinjiang cattle farms showed distinct single PCR bands with high specificity, and the qPCR assay achieved a sensitivity of up to 10⁻⁵ µg/µL. This study established an efficient and broad-spectrum molecular typing and detection method for E. coli phages, providing a powerful preliminary screening tool for phage selection. Full article

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19 pages, 2230 KB

Open AccessArticle

Prevalence of Biofilm-Forming and Antibiotic-Resistant Coagulase-Negative Staphylococci Isolated from Hospitalized Patients in an Orthopedic Clinic

by Tatiana Szabóová, Gabriela Gregová, Ján Király, Nikola Dančová, Vanda Hajdučková, Patrícia Hudecová, Simona Hisirová, Peter Polan and Viera Lovayová

Pathogens 2026, 15(1), 120; https://doi.org/10.3390/pathogens15010120 - 21 Jan 2026

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Abstract

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) are a major cause of infectious diseases, owing to their ability to form biofilms and colonize community and hospital environments. MRCoNS strains were identified using biochemical tests, an MALDI-TOF MS analyzer, and PCR-based 16S rRNA gene confirmation. This study [...] Read more.

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) are a major cause of infectious diseases, owing to their ability to form biofilms and colonize community and hospital environments. MRCoNS strains were identified using biochemical tests, an MALDI-TOF MS analyzer, and PCR-based 16S rRNA gene confirmation. This study was designed to assess antibiotic resistance and biofilm-forming capacity and to determine the presence of the mecA, mecC, agrA, srtA, icaABCD, bap, fnbAB, and clfAB genes in MRCoNS isolates. From patients undergoing random screening during hospitalization in the Orthopedics Clinic in Slovakia, 28 strains of MRCoNS were identified: S. epidermidis (n = 10), S. hominis (n = 8), S. haemolyticus (n = 4), S. lugdunensis (n = 3), while S. simulans, S. pasteuri, and S. warneri were detected only once. The highest rates of resistance were observed for ampicillin, oxacillin, rifampicin, trimethoprim (100%), and erythromycin (62%). The mecA gene was detected in 12 analyzed isolates. In 12 isolates, MDR, strong efflux pump activity, and strong or moderate biofilm formation were simultaneously detected. Our findings highlight the problems posed by biofilm-forming, resistant CoNS in hospitalized patients and the importance of diagnostics, separation, rapid treatment, and proper hospital hygiene. Full article

(This article belongs to the Special Issue New Insights into Antibiotic-Resistant Pathogens Within the One Health Framework: Epidemiology, Mechanisms and Strategies for Eradication)

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14 pages, 761 KB

Open AccessArticle

Clinical and Epidemiological Characteristics of an Oropouche Virus Outbreak in Loreto, Peru (October 2024–March 2025)

by Miguel Ángel Rojo-Pérez, Edgar A. Ramírez-García and Jara Llenas-García

Pathogens 2026, 15(1), 119; https://doi.org/10.3390/pathogens15010119 - 21 Jan 2026

Viewed by 732

Abstract

Oropouche virus (OROV) has emerged as a significant arboviral pathogen in South America, responsible for recurrent outbreaks of febrile illness. In the Loreto region of Peru, more than 600 cases were reported in 2024, markedly exceeding expected incidence rates. We conducted a retrospective [...] Read more.

Oropouche virus (OROV) has emerged as a significant arboviral pathogen in South America, responsible for recurrent outbreaks of febrile illness. In the Loreto region of Peru, more than 600 cases were reported in 2024, markedly exceeding expected incidence rates. We conducted a retrospective observational study using clinical–epidemiological records of all RT-qPCR-confirmed cases of Oropouche fever from the Regional Health Directorate of Loreto between October 2024 and March 2025. A total of 100 confirmed cases were identified. The most frequent symptoms were fever (88%), headache (78%), and myalgia (72%). No atypical or neurological presentations were reported. No severe cases or deaths occurred. Eight patients required hospitalization, mainly due to severe abdominal pain, persistent vomiting, arthralgia, and pregnancy. Six pregnant women were identified; three experienced pregnancy complications, though no fetal malformations or miscarriages were observed. This outbreak represents a new OROV epidemic in the region, with fewer cases than in 2024 and predominantly mild clinical courses. Although outcomes were generally favorable, the occurrence of complications in pregnant women underscores the importance of continued molecular surveillance and targeted public health interventions. Full article

(This article belongs to the Special Issue Understanding Emerging and Re-Emerging Viral Infections)

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21 pages, 3024 KB

Open AccessArticle

A Predictive Computational Framework for Staphylococcus aureus Biofilm Growth Stages in Hydrodynamic Conditions

by Sarees Shaikh, Abiye Mekonnen, Abdul Nafay Saleem and Patrick Ymele-Leki

Pathogens 2026, 15(1), 118; https://doi.org/10.3390/pathogens15010118 - 21 Jan 2026

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Abstract

Biofilms formed by Staphylococcus aureus on medical devices and tissue surfaces are a major contributor to persistent infections due to their resistance to antibiotics. Hydrodynamic forces in physiological and device-associated environments significantly influence biofilm development, yet the dynamics of detachment and regrowth under [...] Read more.

Biofilms formed by Staphylococcus aureus on medical devices and tissue surfaces are a major contributor to persistent infections due to their resistance to antibiotics. Hydrodynamic forces in physiological and device-associated environments significantly influence biofilm development, yet the dynamics of detachment and regrowth under flow remain poorly quantified. In this study, biofilm surface coverage was measured in microfluidic flow assays across combinations of shear rates and nutrient concentrations. A computational workflow was used to segment biofilm trajectories into three kinetic phases—growth, exodus, and regrowth—based on surface coverage dynamics. Each phase was modeled using parametric functions, and fitted parameters were interpolated across experimental conditions to reconstruct biofilm lifecycles throughout the flow–nutrient conditions. The analysis revealed that intermediate shear rates triggered early detachment events while suppressing subsequent regrowth, whereas lower and higher shear regimes favored biofilm persistence. The resulting model enables quantitative comparison of condition-specific biofilm behaviors and identifies key thresholds in mechanical and nutritional inputs that modulate biofilm stability. These findings establish a phase-resolved framework for studying S. aureus biofilms under hydrodynamic stress and support future development of targeted strategies to control biofilm progression in clinical and engineered systems. Full article

(This article belongs to the Special Issue Thinking Out-of-the-Box: Innovative Approaches for the Treatment of Biofilm-Related Infections)

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12 pages, 534 KB

Open AccessArticle

Anthelmintic Activity of Protocatechuic Acid Against Ivermectin-Susceptible and Resistant Haemonchus contortus Strains

by Jorge Alberto Cortes-Morales, Agustín Olmedo-Juárez, Manasés González-Cortazar, Alejandro Zamilpa, María Eugenia López-Arellano, Humberto Flores-Bustamante, Dante Avilés-Montes, Juan Manuel Rivas-González, César Sotelo-Leyva and David Osvaldo Salinas-Sánchez

Pathogens 2026, 15(1), 117; https://doi.org/10.3390/pathogens15010117 - 21 Jan 2026

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Abstract

The frequent and indiscriminate use of all classes of synthetic anthelmintics to deworm small ruminants has decreased their effectiveness in a worldwide problem of anthelmintic resistance. Using active plant metabolites with anthelmintic properties has become a suggested alternative to control parasitic helminths. The [...] Read more.

The frequent and indiscriminate use of all classes of synthetic anthelmintics to deworm small ruminants has decreased their effectiveness in a worldwide problem of anthelmintic resistance. Using active plant metabolites with anthelmintic properties has become a suggested alternative to control parasitic helminths. The present study investigated the ovicidal and larvicidal activity of a fraction (CnF4) containing protocatechuic acid (3,4-dihydroxybenzoic acid) from Chamaecrista nictitans (Fabaceae) and a commercial standard of protocatechuic acid against strains of the parasitic nematode Haemonchus contortus susceptible (HcIVM-S) and resistant (HcIVM-R) to ivermectin, using egg hatch inhibition (EHI) and L3 larval mortality assays. The CnF4 fraction showed an EHI greater than 90% at 0.8 mg/mL against HcIVM-S and an EHI = 88.39% at 1.6 mg/mL against HcIVM-R. The commercial standard of protocatechuic acid displayed an EHI of 97.49% at 0.25 mg/mL against HcIVM-S and an EHI greater than 98% at 0.5 mg/mL. In the larval mortality assays, protocatechuic acid caused 72.4% larval mortality of HcIVM-S at 8 mg/mL and 53.2% mortality of HcIVM-R at 16 mg/mL. These results indicate that protocatechuic acid was more effective in inhibiting egg hatching and causing larval mortality against HcIVM-S compared to HcIVM-R. Full article

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20 pages, 20781 KB

Open AccessReview

Unlocking the Black Box: The Molecular Dialogue Between ASFV and Its Tick Host

by Alina Rodríguez-Mallon and Thailin Lao González

Pathogens 2026, 15(1), 116; https://doi.org/10.3390/pathogens15010116 - 21 Jan 2026

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Abstract

African Swine Fever is a lethal hemorrhagic disease caused by a DNA virus that affects domestic and wild pigs, causing serious economic losses in the swine industry. African Swine Fever virus (ASFV) is maintained in a sylvatic cycle that includes wildlife and Ornithodoros [...] Read more.

African Swine Fever is a lethal hemorrhagic disease caused by a DNA virus that affects domestic and wild pigs, causing serious economic losses in the swine industry. African Swine Fever virus (ASFV) is maintained in a sylvatic cycle that includes wildlife and Ornithodoros tick species. A huge investigation about ASFV structure and its infection process in pigs has been carried out in recent years, and although these studies have increased our knowledge about its pathogenesis, there are still many unclear aspects about which immune responses protect swine hosts against the disease caused by this virus. The mechanisms of ASFV infection in ticks are even less well understood. This infection is long term and persistent, with relatively high levels of virus replication in different tick tissues. According to specific infected tissues, the Ornithodoros tick species that are ASFV-competent vectors show transstadial, transovarial and/or venereal transmissions. This review is focused on the main process taking place at the virus–vector interface, summarizing the latest findings about the molecular and cellular aspects of ASFV infection in ticks, which could constitute the basis for developing novel strategies to interrupt the arthropod transmission cycle. Full article

(This article belongs to the Section Ticks)

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15 pages, 1262 KB

Open AccessArticle

Genetic Diversity and Molecular Epidemiology of Mycobacterium tuberculosis Complex Clinical Isolates in New Brunswick, Canada—A Retrospective Chart Review

by Isdore Chola Shamputa, Derek J. Gaudet, Jason McKinney, Kim Barker, Hafid Soualhine, Catherine Yoshida, Meenu Kaushal Sharma and Duncan Webster

Pathogens 2026, 15(1), 115; https://doi.org/10.3390/pathogens15010115 - 20 Jan 2026

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Abstract

The incidence of tuberculosis disease (TBD) in New Brunswick (NB) is low but has been rising over the past decade. Analyzing these trends can help identify specific risk factors and transmission patterns to guide targeted public health strategies. This study aimed to provide [...] Read more.

The incidence of tuberculosis disease (TBD) in New Brunswick (NB) is low but has been rising over the past decade. Analyzing these trends can help identify specific risk factors and transmission patterns to guide targeted public health strategies. This study aimed to provide a comprehensive and detailed characterization of TBD in NB by examining data from 1 January 2002, to 31 December 2024. All TB patients with Mycobacterium tuberculosis complex (MTBC) clinical isolates identified in NB healthcare facilities were eligible for inclusion in the study. We analyzed demographic, drug susceptibility, and 24-locus Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) data from 166 patients. Most MTBC isolates were pan-susceptible to first-line anti-tuberculosis drugs (90.9–98.1%), with 2.4% showing multidrug resistance. The MIRU-VNTR demonstrated a high discriminatory power of 0.9982 and a low clustering rate of 20.4%. Two samples from the same patient, collected seven years apart, showed different genetic profiles, suggesting that the second episode was a new infection. The most prevalent MTBC lineage was East African Indian (n = 23, 13%). This study provides early insights into TB trends in NB, including what may be the first recorded case of TB reinfection in NB. Our findings will help guide future TB research, policies, and public health interventions in the region. Full article

(This article belongs to the Section Epidemiology of Infectious Diseases)

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7 pages, 4003 KB

Open AccessCase Report

Congenital Tuberculosis in a Stillborn Calf

by María Fiorella Alvarado Pinedo, Adrián Di Paolo, Martín Zumárraga, Federico Illanes, Damián Moyano, Luis María Peralta and Gabriel Travería

Pathogens 2026, 15(1), 114; https://doi.org/10.3390/pathogens15010114 - 20 Jan 2026

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Abstract

Bovine tuberculosis is a zoonotic infectious disease of cattle caused by the bacterium Mycobacterium bovis. In adult cattle, transmission is mainly via the respiratory route, whereas, in young calves, oral infection is also common. Congenital tuberculosis is rare. The purpose of this [...] Read more.

Bovine tuberculosis is a zoonotic infectious disease of cattle caused by the bacterium Mycobacterium bovis. In adult cattle, transmission is mainly via the respiratory route, whereas, in young calves, oral infection is also common. Congenital tuberculosis is rare. The purpose of this study was to describe in utero infection of a bovine stillbirth. The fetus was necropsied and tissue samples were processed for histopathology, bacteriology and PCR; a sample of the isolated strain was genotyped using spoligotyping. The whole herd was tuberculin skin tested and the dam’s serum was also assessed for the presence of antibodies against bovine tuberculosis with indirect ELISA. The macroscopic findings in different organs were consistent with tuberculosis. The histopathology demonstrated typical granulomatous lesions in the liver, spleen, hepatic and mediastinal lymph nodes. Acid-fast bacilli were observed in the smears stained using the Ziehl–Neelsen method. The colonies isolated were PCR-positive for IS6110 and the spoligotype corresponded to SB0140. The dam of the stillborn was positive for indirect ELISA and reacted to a single caudal skin test with bovine tuberculin. The fetal infection in utero with Mycobacterium bovis was confirmed through necropsy, histopathology and bacteriology, reinforcing the importance of testing young animals. Full article

(This article belongs to the Special Issue Animal Tuberculosis Caused by Mycobacterium tuberculosis complex: Epidemiology, Diagnostic Methods, and Multi-Species Case Analysis)

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12 pages, 1129 KB

Open AccessArticle

Detection of Benzimidazole-Resistant Haemonchus contortus in Domestic and Wild Ruminants in Bosnia and Herzegovina

by Naida Kapo, Teufik Goletić, Adis Softić, Šejla Goletić Imamović, Srđan Gligorić and Jasmin Omeragić

Pathogens 2026, 15(1), 113; https://doi.org/10.3390/pathogens15010113 - 20 Jan 2026

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Abstract

Gastrointestinal nematodes, particularly Haemonchus contortus, represent a major threat to ruminant health and productivity worldwide, largely due to the widespread emergence of anthelmintic resistance. In Bosnia and Herzegovina, benzimidazole resistance has previously been confirmed in domestic ruminants; however, data on wildlife remain [...] Read more.

Gastrointestinal nematodes, particularly Haemonchus contortus, represent a major threat to ruminant health and productivity worldwide, largely due to the widespread emergence of anthelmintic resistance. In Bosnia and Herzegovina, benzimidazole resistance has previously been confirmed in domestic ruminants; however, data on wildlife remain lacking. Given the frequent spatial and temporal overlap between domestic and wild ruminants on shared pastures, this study aimed to investigate the occurrence of benzimidazole-resistant H. contortus genotypes within a multi-host system. During the 2024/2025 season, a total of 111 abomasal samples were collected from sheep (n = 20), lambs (n = 12), goats (n = 17), roe deer (n = 40) and chamois (n = 22) across four localities in Bosnia and Herzegovina (Laktaši, Banja Luka, Modriča and Višegrad). Adult H. contortus specimens were morphologically identified and confirmed using real-time quantitative PCR (rt-qPCR). Benzimidazole resistance was assessed by allele-specific rt-qPCR targeting the F200Y mutation in the β-tubulin isotype 1 gene. Statistically significant interspecies differences in β-tubulin genotype distribution were observed (p < 0.05), primarily driven by variation in the homozygous resistant (RR) genotype. High RR prevalence was detected in sheep (60%), lambs (50%) and roe deer (52.5%), whereas lower proportions were observed in chamois (27.3%) and goats (23.5%). Overall, 44.1% of all analyzed H. contortus isolates carried homozygous resistant alleles, indicating an advanced stage of benzimidazole resistance within this multi-host system. These findings demonstrate that benzimidazole resistance in H. contortus is not confined to domestic livestock but is also present in wild ruminants sharing the same grazing areas, consistent with circulation of resistant parasites within shared grazing systems. Full article

(This article belongs to the Special Issue Parasites of Wildlife and Livestock: Recent Progress and Future Challenges)

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13 pages, 450 KB

Open AccessReview

Arthrographis Infections in Humans—A Narrative Review

by Afroditi Ziogou, Alexios Giannakodimos, Ilias Giannakodimos, Andreas G. Tsantes, Stella Baliou, Petros Ioannou, Georgia Vrioni and George Samonis

Pathogens 2026, 15(1), 112; https://doi.org/10.3390/pathogens15010112 - 20 Jan 2026

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Abstract

Background: Arthrographis spp. are environmental fungi commonly found in soil and compost. Infections caused by Arthrographis species remain an uncommon clinical occurrence. Although these infections are infrequent in the general population, their incidence appears to be elevated among immunocompromised patients or those with [...] Read more.

Background: Arthrographis spp. are environmental fungi commonly found in soil and compost. Infections caused by Arthrographis species remain an uncommon clinical occurrence. Although these infections are infrequent in the general population, their incidence appears to be elevated among immunocompromised patients or those with significant comorbidities. Objectives: This review seeks to examine all documented human cases of Arthrographis spp. infections, with particular focus on aspects such as epidemiology, microbiological features, resistance patterns, therapeutic approaches and associated mortality rates. Methods: A narrative review was performed based on data obtained from the PubMed/MedLine and Scopus databases. Results: A total of 21 articles reported Arthrographis spp. infections in 21 patients. The mean age of affected individuals was 43.62 years, with 66.6% being male. A history of trauma was the most common predisposing factor, present in 33.33% of cases. Fever and abscess formation were the predominant clinical manifestations (28.6%), followed by organ dysfunction in 19% of patients. In vitro, the yeast generally showed susceptibility to voriconazole and itraconazole, with a low rate of resistance to amphotericin B. Clinically, amphotericin B was the most frequently administered antifungal (55%), followed by voriconazole (40%) and itraconazole (30%). The overall mortality rate was 19%, while deaths directly attributable to the infection accounted for 14.3%. Conclusions: Due to the capacity of Arthrographis spp. to cause serious infections, it is important for healthcare providers to consider this organism when dimorphic yeast appears in biological specimens’ cultures, especially in patients with immunosuppression or significant underlying conditions, to facilitate timely and accurate diagnosis. Full article

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23 pages, 5560 KB

Open AccessArticle

Natural Protective Mechanisms of Cucumis callosus Leaves in Escherichia Species-Induced Urinary Tract Infection: An Integrated In Silico and In Vivo Study

by Meenal Sahu, Tripti Paliwal, Radhika Joshi, Arya Kuhu Vishwapriya, Namita Misra, Smita Jain, Gautam Singhvi, Gulshan Kumar, Devesh U. Kapoor, Dipjyoti Chakraborty and Swapnil Sharma

Pathogens 2026, 15(1), 111; https://doi.org/10.3390/pathogens15010111 - 19 Jan 2026

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Abstract

Leaves of Cucumis callosus, traditionally employed in Ayurvedic medicine for the treatment of urinary disorders, were investigated in depth for their therapeutic potential against bacterially induced urinary tract infection (UTI) for the first time. The present work is the first to explore [...] Read more.

Leaves of Cucumis callosus, traditionally employed in Ayurvedic medicine for the treatment of urinary disorders, were investigated in depth for their therapeutic potential against bacterially induced urinary tract infection (UTI) for the first time. The present work is the first to explore the antibacterial activity of C. callosus leaf fractions with an integrative in silico, in vitro, and in vivo approach. Through bioassay-guided fractionation, the chloroform fraction (F1) was identified as the most active, exhibiting potent activity against Uropathogenic Escherichia spp. species. Liquid chromatography–mass spectrometry (LC-MS) analysis of F1 revealed the presence of bioactive compounds, including stigmasterol, 1,2,3,4-tetrahydroisoquinoline, lactose, hydroxy(mesityl)acetic acid, and 2,4-di-tert-butylphenol. Molecular docking studies validated the strong binding affinities of these compounds for bacterial resistance enzymes, including AmpC β-lactamase and carbapenemases, thereby providing plausible mechanisms of antimicrobial action. In vivo studies carried out on female rats infected with Escherichia spp. species revealed a dose-dependent reduction in bacterial load, with a significant decrease in urinary tract inflammation upon F1 administration. Histopathological evaluation confirmed the protective effect, with reduced epithelial damage and inflammation in bladder tissues. These findings indicate significant antibacterial and tissue-protective effects of the C. callosus leaf fraction F1, supporting its ethnomedicinal use and establishing it as a promising phytotherapeutic agent for the treatment of urinary tract infections. Full article

(This article belongs to the Special Issue Current Progress on Bacterial Antimicrobial Resistance)

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22 pages, 2335 KB

Open AccessArticle

Burkholderia pseudomallei in Sarawak, Malaysian Borneo, Remains Highly Susceptible to Trimethoprim-Sulfamethoxazole Despite Resistance to Its Individual Components

by Liana Lantong Sumbu, Tonnii Loong-Loong Sia, Mong-How Ooi, Anand Mohan, Jin-Shyan Wong and Yuwana Podin

Pathogens 2026, 15(1), 110; https://doi.org/10.3390/pathogens15010110 - 19 Jan 2026

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Abstract

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in Sarawak, Malaysian Borneo, where it is represented by a unique gentamicin-susceptible population. Despite trimethoprim-sulfamethoxazole (co-trimoxazole) being the cornerstone of eradication therapy, emerging reports of elevated minimum inhibitory concentrations (MICs) among Sarawak isolates [...] Read more.

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in Sarawak, Malaysian Borneo, where it is represented by a unique gentamicin-susceptible population. Despite trimethoprim-sulfamethoxazole (co-trimoxazole) being the cornerstone of eradication therapy, emerging reports of elevated minimum inhibitory concentrations (MICs) among Sarawak isolates have raised concerns over its clinical efficacy. We performed a retrospective and comprehensive antibiotic susceptibility assessment of clinical B. pseudomallei isolates from hospitals across Sarawak. Susceptibility to trimethoprim-sulfamethoxazole was determined using disk diffusion and the E-test, interpreted by both CLSI and EUCAST guidelines. Resistance to the individual components, trimethoprim and sulfamethoxazole, was characterized by broth microdilution. The results demonstrated a high prevalence of trimethoprim-sulfamethoxazole susceptibility, with 96.3% of isolates susceptible by CLSI criteria and 97.6% by EUCAST criteria. Interestingly, broth microdilution revealed that resistance to trimethoprim and sulfamethoxazole individually did not confer resistance to the synergistic combination. Our analysis validated CLSI guidelines as the most reliable standard for antimicrobial resistance surveillance in this region. This study provides evidence that trimethoprim-sulfamethoxazole remains effective for melioidosis treatment in Sarawak, offering crucial reassurance to clinicians. The paradoxical finding of susceptibility to the drug combination despite resistance to its individual components underscores the critical importance of the synergistic activity of trimethoprim-sulfamethoxazole and highlights the need for further investigation into the molecular basis of resistance in this distinct B. pseudomallei population. Full article

(This article belongs to the Special Issue Updates on Human Melioidosis)

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13 pages, 1806 KB

Open AccessArticle

Listeria monocytogenes in Jiaxing: Whole-Genome Sequencing Reveals New Threats to Public Health

by Lei Gao, Wenjie Gao, Ping Li, Miaomiao Jia, Xuejuan Liu, Peiyan He, Henghui Wang, Yong Yan and Guoying Zhu

Pathogens 2026, 15(1), 109; https://doi.org/10.3390/pathogens15010109 - 19 Jan 2026

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Abstract

(1) Background: Listeria monocytogenes (Lm) is recognized by the World Health Organization (WHO) as one of the four principal foodborne pathogens. This study aimed to investigate the molecular characteristics of Lm isolates from Jiaxing, China, using whole-genome sequencing (WGS) to enhance our understanding [...] Read more.

(1) Background: Listeria monocytogenes (Lm) is recognized by the World Health Organization (WHO) as one of the four principal foodborne pathogens. This study aimed to investigate the molecular characteristics of Lm isolates from Jiaxing, China, using whole-genome sequencing (WGS) to enhance our understanding of their molecular epidemiology. (2) Methods: A total of 39 foodborne Lm isolates and 7 clinical Lm isolates were analyzed via WGS to identify resistance genes, virulence factors, lineage, sequence type (ST), and clonal complex (CC). Antibiotic susceptibility was assessed using Minimum Inhibitory Concentration (MIC) testing, and serotypes were confirmed via multiplex PCR. (3) Results: We found that 39 food isolates were mainly lineage II (66.67%), with 13 STs; ST8 was the dominant ST, and 2 new types, ST3210 and ST3405, were found. Among the seven clinical isolates, lineage I was dominant (57.14%), and ST87 was the dominant ST. Serotype 1/2a was dominant, accounting for 54.35%, followed by 1/2b, which accounted for 36.96%. The overall antimicrobial resistance rate was 13.04%, with a multidrug resistance rate of 2.17%. All strains harbored LIPI-1 and LIPI-2, and five strains carried LIPI-3 genes: one strain belonged to ST619 of lineage I, two strains belonged to ST224 of lineage I, and two strains belonged to ST11 of lineage II. (4) Conclusions: This study clarified the genotype and serotype characteristics of Listeria monocytogenes in Jiaxing, as well as their molecular characteristics relating to drug resistance and virulence, thus providing a technical basis for improving exposure risk assessment of Listeria monocytogenes. Continuous monitoring, prevention, and control are recommended to further improve regional public health and safety. Full article

(This article belongs to the Section Bacterial Pathogens)

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13 pages, 945 KB

Open AccessArticle

Comparison of Effectiveness Between Cysticidal and Surgical Treatments in Patients with Intraventricular Neurocysticercosis: A Single-Center Experience

by Alex Aarón Agallo-Martínez, Rebeca Ramírez-Bustamante, Polet Juárez-Ortíz, Ximena Gutiérrez-Bonilla, Sergio Moreno Jiménez, Roger Carrillo-Mezo and Agnès Fleury

Pathogens 2026, 15(1), 108; https://doi.org/10.3390/pathogens15010108 - 19 Jan 2026

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Abstract

Neurocysticercosis (NCC) remains a major public health problem in endemic countries. Clinical manifestations and therapeutic strategies vary depending on the location of the parasite. While the benefits of cysticidal treatment are well established for parenchymal and subarachnoid NCC, the optimal management of intraventricular [...] Read more.

Neurocysticercosis (NCC) remains a major public health problem in endemic countries. Clinical manifestations and therapeutic strategies vary depending on the location of the parasite. While the benefits of cysticidal treatment are well established for parenchymal and subarachnoid NCC, the optimal management of intraventricular NCC (IVNCC) remains controversial. We conducted a retrospective study of 51 patients: 37 (72.54%) received cysticidal treatment as initial therapy and 14 (27.45%) underwent neurosurgical intervention. Although six months after treatment, the proportion of patients with inactive disease was higher in the surgical group, no significant difference was observed after one year. Patients in both groups showed significant improvement in functionality as measured by the Karnofsky Index (KI), with no significant difference between groups. These results are consistent with cysticidal treatment being a valid therapeutic option for IVNCC, with the choice of management largely determined by the available medical infrastructure and the degree of specialization of healthcare personnel. Full article

(This article belongs to the Section Parasitic Pathogens)

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27 pages, 4476 KB

Open AccessArticle

Kinetics of Biomarkers for Therapeutic Assessment in Swiss Mice Infected with a Virulent Trypanosoma cruzi Strain

by María Fernanda Alves-Rosa, Doriana Dorta, Alexa Prescilla-Ledezma, Jafeth Carrasco, Leighanne Bonner, Jon J. Tamayo, Michelle G. Ng, Adelenis Vega, Melany Morales, Davis Beltran, Rosa De Jesús and Carmenza Spadafora

Pathogens 2026, 15(1), 107; https://doi.org/10.3390/pathogens15010107 - 19 Jan 2026

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Abstract

Chagas disease (CD), caused by Trypanosoma cruzi, is a neglected tropical illness affecting 6–8 million people in Latin America. Reaching scholarly consensus on the host response to T. cruzi infection remains a significant challenge, primarily due to substantial heterogeneity in outcomes driven [...] Read more.

Chagas disease (CD), caused by Trypanosoma cruzi, is a neglected tropical illness affecting 6–8 million people in Latin America. Reaching scholarly consensus on the host response to T. cruzi infection remains a significant challenge, primarily due to substantial heterogeneity in outcomes driven by both the choice of animal model and the infecting parasite’s discrete typing unit (DTU). This variability complicates the evaluation and comparison of new therapeutic compounds against existing drugs, namely benznidazole and nifurtimox. This study provides a comprehensive, kinetic, multifaceted characterization of the acute infection using the highly virulent T. cruzi Y strain (TcII) in outbred Swiss mice. Here, crucial infection parameters are presented, including the optimal infective dose, the parasitemia dynamics, tissue damage markers, hematological profiles, cytokine production (Th1/Th2/Th17/Th22), and molecular parasite identification in target organs (heart, colon, esophagus, spleen, and liver) across the span of the infection. The novelty of this study lies in the kinetic integration of these parameters within a defined model; rather than presenting isolated data points, we demonstrate how the biochemical, physiological, and clinical signs and immunological responses, with the resulting organ involvement, evolve and interact over time. To complete the report, a necropsy evaluation was performed at the end of the acute, fatal infection, and it is presented here. This study fulfills a long-standing recommendation from diverse drug discovery groups for the creation of a definitive reference model to standardize preclinical testing for anti-Chagasic agents. Full article

(This article belongs to the Special Issue New Insights into Protozoa Parasites: Essential Processes and Drug Targets)

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22 pages, 626 KB

Open AccessReview

Sheep Genetic Resistance to Gastrointestinal Nematode Infections: Current Insights from Transcriptomics and Other OMICs Technologies—A Review

by Krishani Sinhalage, Guilherme Henrique Gebim Polizel, Niel A. Karrow, Flavio S. Schenkel and Ángela Cánovas

Pathogens 2026, 15(1), 106; https://doi.org/10.3390/pathogens15010106 - 19 Jan 2026

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Abstract

Gastrointestinal nematode (GIN) infections are the most prevalent parasitic diseases in grazing sheep worldwide, causing significant productivity losses, high mortality and, as a result, economic losses and emerging animal welfare concerns. Conventional control strategies, primarily relying on anthelmintic treatments, face limitations due to [...] Read more.

Gastrointestinal nematode (GIN) infections are the most prevalent parasitic diseases in grazing sheep worldwide, causing significant productivity losses, high mortality and, as a result, economic losses and emerging animal welfare concerns. Conventional control strategies, primarily relying on anthelmintic treatments, face limitations due to rising drug resistance and environmental concerns, underscoring the need for sustainable alternatives. Selective breeding for host genetic resistance has emerged as a promising strategy, while recent advances in transcriptomics and integrative omics research are providing deeper insights into the immune pathways and molecular and genetic mechanisms that underpin host–parasite interactions. This review summarizes current evidence on transcriptomic signatures associated with resistance and susceptibility to H. contortus and T. circumcincta GIN infections, highlighting candidate genes, functional genetic markers, key immune pathways, and regulatory networks. Furthermore, we discuss how other omics approaches, including genomics, proteomics, metabolomics, microbiome, and multi-omics integrations, provide perspectives that enhance the understanding of the complexity of the GIN resistance trait. Transcriptomic studies, particularly using RNA-Sequencing technology, have revealed differential gene expression, functional genetic variants, such as SNPs and INDELs, in expressed regions and splice junctions, and regulatory long non-coding RNAs that distinguish resistance from susceptible sheep, highlighting pathways related to Th2 immunity, antigen presentation, tissue repair, and stress signaling. Genomic analyses have identified SNPs, QTL, and candidate genes linked to immune regulation and parasite resistance. Proteomic and metabolomic profiling further elucidates breed- and tissue-specific alterations in protein abundance and metabolic pathways, while microbiome studies demonstrate distinct microbial signatures in resistant sheep, suggesting a role in modulating host immunity. In conclusion, emerging multi-omics approaches and their integration strategies provide a comprehensive framework for understanding the complex host–parasite interactions that govern GIN resistance, offering potential candidate biomarkers for genomic selection and breeding programs aimed at developing sustainable, parasite-resistant sheep populations. Full article

(This article belongs to the Special Issue Parasitic Helminths and Control Strategies)

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21 pages, 2319 KB

Open AccessSystematic Review

Torque Teno Virus (TTV) Plasma Load and Immune Reconstitution Post-Transplantation in Patients with Lymphoproliferative Disorders: A Systematic Review

by Eugenia Quiros-Roldan, Martina Salvi, Maria Alberti, Giorgio Tiecco, Giorgio Biasiotto, Roberto Bresciani, Diego Bertoli, Alessandra Sottini and Maria Antonia De Francesco

Pathogens 2026, 15(1), 105; https://doi.org/10.3390/pathogens15010105 - 19 Jan 2026

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Abstract

Torque Teno Virus (TTV), a common and genetically diverse component of the human virome, is not linked to any known disease but reflects immune status. Its plasma viral load has shown clinical relevance in solid organ transplant recipients, correlating it with immunosuppression when [...] Read more.

Torque Teno Virus (TTV), a common and genetically diverse component of the human virome, is not linked to any known disease but reflects immune status. Its plasma viral load has shown clinical relevance in solid organ transplant recipients, correlating it with immunosuppression when present at high levels. However, the clinical significance of TTV viral load in hematopoietic stem cell transplantation (HSCT) recipients is less understood. This systematic review aims to evaluate whether plasma TTV DNA load directly correlates with the degree of T-cell immune reconstitution after HSCT, supporting its potential role as a biomarker for immune competence. The study protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD420251116208) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Twenty-one studies were included. The results showed concordant data about TTV kinetics with peak levels reaching approximately between +90 to +120 days after transplantation. Contradictory results have instead been found for the association of TTV load with immune parameters (lymphocyte counts, viral opportunistic infection, and development of acute graft versus host diseases). Even if a low-risk bias assessment was classified in most studies (67%), it was possible to identify important clinical and methodological differences between them, which might account for the different findings observed. Therefore, future larger studies with standardized protocols are needed to assess whether TTV viral load can serve as a reliable tool for guiding clinical decisions in the context of HSCT. Full article

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

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32 pages, 950 KB

Open AccessReview

Gammaretrovirus Infections in Humans in the Past, Present, and Future: Have We Defeated the Pathogen?

by Antoinette Cornelia van der Kuyl

Pathogens 2026, 15(1), 104; https://doi.org/10.3390/pathogens15010104 - 19 Jan 2026

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Abstract

Gammaretroviruses are ubiquitous pathogens, often associated with the induction of neoplasia, especially leukemia, lymphoma, and sarcoma, and with a propensity to target the germline. The latter trait has left extensive evidence of their infectious competence in vertebrate genomes, the human genome being no [...] Read more.

Gammaretroviruses are ubiquitous pathogens, often associated with the induction of neoplasia, especially leukemia, lymphoma, and sarcoma, and with a propensity to target the germline. The latter trait has left extensive evidence of their infectious competence in vertebrate genomes, the human genome being no exception. Despite the continuing activity of gammaretroviruses in mammals, including Old World monkeys, apes, and gibbons, humans have apparently evaded novel infections by the virus class for the past 30 million years or so. Nevertheless, from the 1970s onward, cell culture studies repeatedly discovered gammaretroviral components and/or virus replication in human samples. The last novel ‘human’ gammaretrovirus, identified in prostate cancer tissue, culminated in the XMRV frenzy of the 2000s. In the end, that discovery was shown to be due to lab contamination with a murine gammaretrovirus. Contamination is also the likely source of the earlier findings. Complementation between genes of partially defective endogenous proviruses could have been another source of the virions observed. However, the capacity of many gammaretroviruses to replicate in human cell lines, as well as the presence of diverse infectious gammaretroviral species in our animal companions, for instance in mice, cats, pigs, monkeys, chickens, and bats, does not make a transmission to humans an improbable scenario. This review will summarize evidence for, or the lack of, gammaretrovirus infections in humans in the past, present, and near future. Aspects linked to the probabilities of novel gammaretrovirus infections in humans, regarding exposure risk in connection to modern lifestyle, geography, diet, and habitat, together with genetic and immune factors, will also be part of the review, as will be the estimated consequences of such novel infections. Full article

(This article belongs to the Section Viral Pathogens)

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11 pages, 1445 KB

Open AccessArticle

Antiviral Role of Surface Layer Protein A (SlpA) of Lactobacillus acidophilus

by Govindaraj Anumanthan, Ananta Prasad Arukha, Ayalew Mergia and Bikash Sahay

Pathogens 2026, 15(1), 103; https://doi.org/10.3390/pathogens15010103 - 19 Jan 2026

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Abstract

Norovirus is associated with vomiting and diarrhea and, in severe cases, can result in death. Currently, there is no effective treatment or vaccine for this virus. Bilateral interactions have been reported between gut microbiota and viral infection. Our laboratory has been studying the [...] Read more.

Norovirus is associated with vomiting and diarrhea and, in severe cases, can result in death. Currently, there is no effective treatment or vaccine for this virus. Bilateral interactions have been reported between gut microbiota and viral infection. Our laboratory has been studying the Surface layer protein A (SlpA) of a human isolate of Lactobacillus acidophilus. Previously, we reported that SlpA induces a variety of antiviral genes in human dendritic cells, suggesting it may prevent viral replication. SlpA binds to its cognate receptor SIGNR3-expressed on limited dendritic cells. To achieve a homogenous expression of the gene, we modified murine macrophage RAW 264.7 (RAW) cells by transducing SIGNR3-expressing lentivirus, resulting in RAWS cells. These cells and wild-type RAW cells were pretreated with SlpA for one hour and infected with 1 MOI of murine norovirus (MNV). We report that RAWS cells, when treated with SlpA, enhance the antiviral program to prevent viral replication, as determined by quantitative real-time PCR and viral titer. RNA isolated from MNV-infected cells revealed an elevation in two critical antiviral genes, Iigp1 and Ifit1, in SlpA-treated RAWS cells, potentially preventing viral replication. Full article

(This article belongs to the Section Viral Pathogens)

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29 pages, 5959 KB

Open AccessReview

Inside Enemy Lines: Adhesion, Invasion, and Intracellular Persistence of Acinetobacter baumannii in the Respiratory Epithelium

by Dolores Limongi, Daniela Scribano, Anna Teresa Palamara and Cecilia Ambrosi

Pathogens 2026, 15(1), 102; https://doi.org/10.3390/pathogens15010102 - 19 Jan 2026

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Abstract

Acinetobacter baumannii is a critical pathogen and a leading cause of hospital-acquired pneumonia, especially in immunocompromised patients. Although most research has focused on antimicrobial resistance, growing evidence shows that A. baumannii can efficiently adhere to, invade, and persist within human airway epithelial cells. [...] Read more.

Acinetobacter baumannii is a critical pathogen and a leading cause of hospital-acquired pneumonia, especially in immunocompromised patients. Although most research has focused on antimicrobial resistance, growing evidence shows that A. baumannii can efficiently adhere to, invade, and persist within human airway epithelial cells. Thus, the aim of this review is to summarize current knowledge on the mechanisms used by A. baumannii to establish infection, highlighting the bacterial traits responsible for attachment to airway epithelia, entry into host cells, manipulation of intracellular trafficking pathways to avoid degradation, metabolic adaptation to the host environment, and interference with immune defenses. The findings reported herein come from host–pathogen studies performed using epithelial cell lines, Galleria mellonella, and murine models, and from human primary airway cells. Despite the prominent role of the outer membrane protein OmpA, it is clear that A. baumannii pathogenicity relies on multiple, often redundant, virulence strategies to secure its intracellular niche and resist host pressures. Remarkably, strain heterogeneity in virulence traits between lab-domesticated and clinical isolates supports differential intracellular behavior and pathogenic potential. A deeper understanding of A. baumannii infection mechanisms is essential to design anti-virulence strategies that disarm this life-threatening bacterium, reduce selective pressure, limit resistance, and guide next-generation therapeutic interventions. Full article

(This article belongs to the Special Issue Thinking Inside the Host: Strategies of Facultative Intracellular Bacteria)

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17 pages, 1198 KB

Open AccessArticle

Comparative Analysis of Oral and Oropharyngeal Mucosal Lesions of American Tegumentary Leishmaniasis and Other Infectious Granulomatous Diseases and Squamous Cell Carcinoma

by Clarissa Souza Mota Reis, João Gustavo Corrêa Reis, Raquel de Vasconcellos Carvalhaes de Oliveira, Cláudia Maria Valete and Fátima Conceição-Silva

Pathogens 2026, 15(1), 101; https://doi.org/10.3390/pathogens15010101 - 17 Jan 2026

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Abstract

American tegumentary leishmaniasis (ATL) and other infectious granulomatous diseases (IGDs) may present with oral/oropharyngeal mucosal lesions (OOPML). IGD-OOPML can result from fungal, parasitic, or bacterial infections, and squamous cell carcinoma (SCC) represents the main differential diagnosis. ATL, other IGD, and SCC share overlapping [...] Read more.

American tegumentary leishmaniasis (ATL) and other infectious granulomatous diseases (IGDs) may present with oral/oropharyngeal mucosal lesions (OOPML). IGD-OOPML can result from fungal, parasitic, or bacterial infections, and squamous cell carcinoma (SCC) represents the main differential diagnosis. ATL, other IGD, and SCC share overlapping clinical and epidemiological features, making diagnostic suspicion challenging. This study compared sociodemographic and clinical characteristics among ATL, other IGD, and SCC. Descriptive, comparative, and multivariable logistic regression analyses were performed. Among 7551 patients, 213 met inclusion criteria (83-SCC and 130-IGD). Except for smoking, which differed only between ATL and SCC, most IGD parameters were similar. Male patients predominated in all groups. SCC patients were significantly older (p < 0.001) and had a shorter median disease duration (p = 0.007). The presence of pain increased the odds of SCC-OOPML by 3.96 times (95% CI 1.97–12.51). SCC patients were more likely to present lesions in a single subsite, either the oral cavity or oropharynx. Painful, ulcerated, or exophytic lesions favored SCC diagnosis, whereas infiltrative, granular, or mulberry-like lesions, involvement of multiple subsites, or associated nasal and laryngeal lesions suggested IGDs. Although clinical differentiation remains difficult, these findings may support early diagnostic suspicion, prompt treatment, and reduced sequelae. Full article

(This article belongs to the Special Issue Leishmania & Leishmaniasis)

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15 pages, 1984 KB

Open AccessArticle

Genetic Determinants Linked to MDR/XDR in Pseudomonas aeruginosa Strains from a Mexican Tertiary Hospital

by Liliana Nicolas-Sayago, Miguel Ángel Loyola-Cruz, Yesseny Vásquez-Martínez, Marcelo Cortez-San Martín, Laura Margarita Márquez-Valdelamar, Clemente Cruz-Cruz, Emilio Mariano Durán-Manuel, Mireya Ruíz-Valdés, Claudia Camelia Calzada-Mendoza, Araceli Rojas-Bernabé, María Concepción Tamayo-Ordóñez, Yahaira de Jesús Tamayo-Ordóñez, Julio César Castañeda-Ortega, Briceida López-Martínez, Benito Hernández-Castellanos, Daniela Moreno-Torres, Graciela Castro-Escarpulli and Juan Manuel Bello-López

Pathogens 2026, 15(1), 100; https://doi.org/10.3390/pathogens15010100 - 17 Jan 2026

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Abstract

Background: Pseudomonas aeruginosa is one of the leading agents causing healthcare-associated infections (HAIs) due to its intrinsic resistance, its capacity to acquire resistance mechanisms, and its persistence in hospital environments. In Mexico, it ranks among the most frequently reported pathogens in national surveillance [...] Read more.

Background: Pseudomonas aeruginosa is one of the leading agents causing healthcare-associated infections (HAIs) due to its intrinsic resistance, its capacity to acquire resistance mechanisms, and its persistence in hospital environments. In Mexico, it ranks among the most frequently reported pathogens in national surveillance systems. The aim of this study was to characterize antimicrobial resistance profiles and the genetic determinants associated with MDR/XDR phenotypes in P. aeruginosa strains from HAIs at Hospital Juárez de México (HJM). Methods: Sixty-three strains from patients with HAIs were analyzed. Identification was confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing followed CLSI guidelines. MDR/XDR phenotypes were classified according to the Latin American consensus for categorizing MDR, XDR, and PDR pathogens. Screening for resistance mechanisms was carried out by PCR for the main β-lactamases circulating at HJM. Finally, mutations in the oprD gene were detected in imipenem-resistant isolates through amino acid sequence alignment. Results: Resistant phenotypes allowed the identification of MDR and XDR profiles. Only the metallo-β-lactamase bla_VIM was detected. Analysis of oprD porin sequences revealed recurrent mutations (S103T, T115K, L170F, G186P, and T189V) associated with imipenem resistance. Conclusions: In P. aeruginosa, the presence of bla_VIM and structural alterations in OprD confirms the multifactorial nature of carbapenem resistance. These findings underscore the need to strengthen microbiological surveillance programs and antimicrobial stewardship strategies to mitigate the impact and spread of MDR/XDR isolates. Full article

(This article belongs to the Special Issue Classic and Emerging Pathogens as a Cause of Healthcare-Associated Infections: Current Knowledge and Future Approaches)

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15 pages, 2077 KB

Open AccessArticle

Phage PM16 Therapy Induce Long-Term Protective Immunity Against Proteus mirabilis via Macrophage Priming

by Lina Al Allaf, Anton V. Chechushkov, Vera V. Morozova, Yulia N. Kozlova, Tatiana A. Ushakova and Nina V. Tikunova

Pathogens 2026, 15(1), 99; https://doi.org/10.3390/pathogens15010099 - 16 Jan 2026

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Abstract

Bacteriophages, traditionally viewed solely as antibacterial agents, are increasingly being studied for their immunomodulatory properties. In this study, we demonstrate that PM16 phage therapy not only effectively controls subcutaneous Proteus mirabilis infection in mice but also induces long-term specific humoral immunity against subsequent [...] Read more.

Bacteriophages, traditionally viewed solely as antibacterial agents, are increasingly being studied for their immunomodulatory properties. In this study, we demonstrate that PM16 phage therapy not only effectively controls subcutaneous Proteus mirabilis infection in mice but also induces long-term specific humoral immunity against subsequent reinfection. This immunomodulatory effect was dose-dependent. In vitro, PM16 directly activates macrophages, leading to increased production of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and inducible nitric oxide synthase, and enhances macrophage bactericidal activity against P. mirabilis. We assume that the enhancement of the adaptive immune response is mediated not by the phage acting as a classical antigenic adjuvant but by its ability to prime innate immune cells, specifically macrophages. This priming leads to more efficient bacterial clearance, antigen presentation, and the formation of protective immunological memory. Full article

(This article belongs to the Section Bacterial Pathogens)

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13 pages, 538 KB

Open AccessArticle

Urinary Tract Infection in Patients with Urolithiasis: A Large Retrospective Observational Study of Clinical Features and Microbiological Spectrum

by Mehmet Erinmez and Mehmet Ozturk

Pathogens 2026, 15(1), 98; https://doi.org/10.3390/pathogens15010098 - 16 Jan 2026

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Abstract

Urinary tract infections (UTIs) and urolithiasis exhibit a complex bidirectional relationship in which microbial colonization and urinary obstruction may mutually reinforce each other. This retrospective observational study evaluated clinical and microbiological factors associated with UTI in patients with urolithiasis using a large institutional [...] Read more.

Urinary tract infections (UTIs) and urolithiasis exhibit a complex bidirectional relationship in which microbial colonization and urinary obstruction may mutually reinforce each other. This retrospective observational study evaluated clinical and microbiological factors associated with UTI in patients with urolithiasis using a large institutional dataset. A total of 23,241 urine cultures obtained from 12,708 unique patients were analyzed, comparing individuals with and without urolithiasis. In stone-forming patients, demographic variables, urine pH, hydronephrosis, ureteral double J stent presence and indwelling duration, urinary anomalies, and stone characteristics were assessed. Logistic regression identified independent associations, and ROC analysis defined optimal risk thresholds. UTI were more frequent in the stone group (34.5%) compared with non-stone forming patients (28.9%, p < 0.001). Escherichia coli was the most common uropathogen overall, whereas Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa were significantly enriched in patients with stones. Elevated urine pH (OR: 6.37; CI: 2.67–15.19; p = 0.001) and hydronephrosis (OR: 9.14; CI: 3.74–22.35; p = 0.001) were independently associated with UTI. A stent dwell time above 29.5 days was associated with infection with 85% sensitivity and 54% specificity (AUC: 0.70; CI: 0.68–0.73), and urine pH 6.2 or higher was associated with infection with 86% sensitivity and 67% specificity (AUC: 0.77; CI: 0.75–0.80). These findings underscore that urine alkalinity, obstruction, and prolonged stenting are key factors associated with infection risk, supporting the need for careful stent management and timely microbiological evaluation in patients with urolithiasis. Full article

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16 pages, 773 KB

Open AccessArticle

A Two-Year Study on Swifts (Apus spp.) as Bioindicators of Environmental Antimicrobial Resistance Within a One Health Framework

by Erika Esposito, Raffaele Scarpellini, Tiziano De Lorentis, Anna Zaghini, Giovanna Marliani, Elisabetta Mondo, Stefano Pesaro and Silvia Piva

Pathogens 2026, 15(1), 97; https://doi.org/10.3390/pathogens15010097 - 16 Jan 2026

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Abstract

Antimicrobial resistance (AMR) is a global threat to human, animal and environmental health, underscoring the need for integrated surveillance to understand its dynamics and ecosystem interactions. This study investigated the potential of swifts (Apus spp.), long-distance migratory birds, as valuable bioindicators of [...] Read more.

Antimicrobial resistance (AMR) is a global threat to human, animal and environmental health, underscoring the need for integrated surveillance to understand its dynamics and ecosystem interactions. This study investigated the potential of swifts (Apus spp.), long-distance migratory birds, as valuable bioindicators of environmental AMR dissemination. Four sampling sessions were conducted over two years (2023–2024) at a wildlife rehabilitation center in Trieste, Italy. Buccal and cloacal swabs were collected from 47 swifts: 10 sampled at arrival and 37 before autumn migration. Swabs were streaked on selective media for targeted isolation of Enterobacterales, Bacillales and Lactobacillales, yielding 168 bacterial isolates. Bacteria were identified using MALDI-TOF and antimicrobial susceptibility was assessed through disk diffusion method, using ECOFFs values or “no inhibition zone” criterion. Of the 168 bacterial isolates, 51 (30.36%) were non-wild type (NWT), with highest percentages of NWT isolates for clarithromycin (33.33%), erythromycin (31.50%), clindamycin (21.88%) and tetracycline (14.29%). Methicillin-resistant staphylococci (45.83%) and carbapenem NWT isolates (9.38%) were also detected. Bacillales isolates showed significantly higher NWT proportion (58.33%; p < 0.0001) compared to Enterobacterales and Lactobacillales. These findings, in clinically healthy non-antimicrobial treated swifts, suggest environmental exposure to resistant bacteria, and support a possible role of swifts as bioindicators of environmental AMR contamination, highlighting the need to strengthen environmental AMR surveillance within a One Health perspective. Full article

(This article belongs to the Special Issue Bacterial Infections and Drug Resistance in Wildlife)

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13 pages, 1340 KB

Open AccessArticle

The Controversial Link Between Human Papillomavirus Infection and Esophageal Health: An Exploratory Translational Study

by Maximilian Egg, Markus Wiesmüller, Bertram Aschenbrenner, Lili Kazemi-Shirazi, Werner Dolak, Behrang Mozayani, Reinhard Kirnbauer, Michael Trauner, Bettina Huber and Alessandra Handisurya

Pathogens 2026, 15(1), 96; https://doi.org/10.3390/pathogens15010096 - 15 Jan 2026

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Abstract

Evidence on the contribution of human papillomaviruses (HPVs) to the development of esophageal papillomas is still controversial. Esophageal papillomatosis (EP) is considered an exceedingly rare, but distinct entity within esophageal proliferations, with about 57 cases published so far. Tissues derived from an EP [...] Read more.

Evidence on the contribution of human papillomaviruses (HPVs) to the development of esophageal papillomas is still controversial. Esophageal papillomatosis (EP) is considered an exceedingly rare, but distinct entity within esophageal proliferations, with about 57 cases published so far. Tissues derived from an EP case and from non-EP esophageal papillomas were investigated for the presence of HPVs and virus-positive specimens were subsequently analyzed for transcriptional activity and surrogate markers of infection. Low-risk type HPV6 DNA was detected in a subset of the esophageal papillomatous tissues, including EP, and a variant isolate belonging to lineage A. In the EP tissue, the abundant expression of the viral E6/E7 mRNA and the presence of HPV6-specific E1^E4 transcripts, the latter indicative of productive viral infection, were detected. An analysis of HPV-specific neutralizing antibodies in sera obtained from the EP case during natural infection as well as after HPV vaccination revealed that, despite extensive manifestation, HPV6-specific antibodies were absent during natural infection and only elicited after repeated HPV immunizations. Although limited by a small sample size, this exploratory study suggests a possible involvement of HPV6 in the development of EP. Furthermore, this study may contribute to the evidence distinguishing EP from less extensive forms of non-EP esophageal squamous papillomas. Full article

(This article belongs to the Special Issue Viral Oncology and Targeted Therapies for Virus-Associated Cancers)

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11 pages, 2529 KB

Open AccessArticle

Ultrastructural Evaluation (SEM) of Ascaris lumbricoides Eggs Treated with Silver Nanoparticles Biosynthesised by Duddingtonia flagrans Using Scanning Electron Microscopy (SEM)

by Carolina Magri Ferraz, João Pedro Barbosa de Assis, Eduarda Cavalini Guerini, Juliany Veloso Leal, Filippe Elias de Freitas Soares, Marcio Fronza, Jackson Victor de Araujo, Luís Madeira de Carvalho and Fabio Ribeiro Braga

Pathogens 2026, 15(1), 95; https://doi.org/10.3390/pathogens15010095 - 15 Jan 2026

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Abstract

Ascaris lumbricoides is one of the most epidemiologically significant soil-transmitted helminths, and the environmental persistence of its eggs is largely attributed to their robust structural architecture. The search for ovicidal alternatives capable of overcoming this barrier has increasingly focused on metallic nanoparticles obtained [...] Read more.

Ascaris lumbricoides is one of the most epidemiologically significant soil-transmitted helminths, and the environmental persistence of its eggs is largely attributed to their robust structural architecture. The search for ovicidal alternatives capable of overcoming this barrier has increasingly focused on metallic nanoparticles obtained through biological synthesis. Scanning electron microscopy (SEM) was employed to evaluate the ultrastructural effects of silver nanoparticles (AgNPs) biosynthesised by the nematophagous fungus Duddingtonia flagrans on A. lumbricoides eggs. Ultraviolet-visible spectroscopy and transmission electron microscopy confirmed the synthesis of AgNPs, revealing predominantly spherical, well-dispersed particles with an average diameter of 9.22 ± 4.9 nm. Cytotoxicity assays indicated an IC₅₀ of 7.7 µg/mL. SEM analyses showed that eggs in the control group maintained intact morphology, with no apparent deformities. In contrast, exposure to AgNPs induced pronounced structural alterations, including marked wrinkling, surface erosion and shell collapse, suggesting disruption of multiple layers. Albendazole alone produced deep linear fissures consistent with internal metabolic failure, though with minimal external erosion. The combined treatment with AgNPs and albendazole resulted in severe degradation. These findings demonstrate that AgNPs exhibit significant ovicidal activity and may serve as effective adjuvants to enhance the action of conventional anthelmintics against highly resistant helminth eggs. Full article

(This article belongs to the Section Parasitic Pathogens)

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Pathogens, Volume 15, Issue 1 (January 2026) – 124 articles

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