Search Results (123)

Enteropathogenic Escherichia coli (EPEC) is a significant diarrheagenic pathotype responsible for severe gastrointestinal infections, particularly in vulnerable populations. The aim of this study is to utilize genome-based in silico analysis to study the structural and functional characteristics of the Type III Secretion System (T3SS) and its core effector proteins in EPEC strains. Representative proteins were selected, with particular interest placed on EscV and EscD as major parts of the export apparatus and the basal body, while the EspA effector protein forms the filamentous structure. Several in silico-based techniques were employed, revealing key structural proteins, core effectors, and adhesion-related proteins among the sequenced isolates. Of the 27 isolates analyzed, only 3 (11%) were found to carry LEE-encoded proteins associated with T3SS structural components (escV, escN, escD, and escU) and core effector proteins (espA, espD, espG, and eae). Structural predictions and Ramachandran plot validations suggested stability and potential functional conservation of T3SS proteins, with EscV and EspA selected for detailed 3D structural modelling. Insights into transmembrane domains, protein–protein interaction, and secondary structures were obtained, providing a comprehensive understanding of T3SS assembly and function. These findings suggest that the T3SS in EPEC consists of stable proteins that enable the system to remain functional. The structural and functional properties of the LEE genes encoding the T3SS in the EPEC pathotype represent promising targets for developing virulence blockers to disrupt the pathogenesis of a broad range of bacteria. This study is the first to report EPEC strains with functional T3SS in South Africa, emphasizing the importance of continued surveillance and molecular characterization of EPEC strains. The findings contribute to the development of targeted interventions to mitigate foodborne infections and improve public health. Full article

Norovirus (NoV) is a leading cause of acute gastroenteritis (AGE) in young children worldwide. Following the introduction of universal rotavirus (RVA) vaccination in Argentina in 2015, the role of NoV in pediatric AGE warrants evaluation. This study aimed to assess the prevalence, clinical characteristics, and molecular diversity of NoV in children under five years of age, comparing the periods before and after RVA vaccine implementation. Methods: A descriptive observational study was conducted in two pediatric hospitals in Argentina. Stool samples were obtained from both outpatient and hospitalized children presenting with acute gastroenteritis (AGE) during two distinct one-year periods: 285 samples from the pre-vaccination period (2011–2012) and 212 samples from the post-vaccination period (2019–2020). NoV, RVA and other viral enteropathogens were detected by RT-qPCR or immunoassay. Positive NoV samples were genotyped by Sanger sequencing of the ORF1/ORF2 junction. Results: NoV was detected in 30.1% (86/285) and 23.5% (50/212) of cases in the pre- and post-vaccination periods, respectively. Children under two years of age and inpatients had significantly higher NoV detection in both periods. NoV mono-infections were more frequent in post-vaccination period (72% vs. 50%). NoV GII predominated in both periods, with increased genotype diversity observed post-vaccination, including GII.3[P12], GII.4 Sydney[P16], GII.6[P7], and GII.2[P16]. Conclusions: NoV remains a major cause of pediatric AGE in Argentina, particularly in children under two years old. Although NoV prevalence did not increase after RVA vaccine introduction, its clinical relevance persists. Continued molecular surveillance is essential to monitor genotype dynamics and implement prevention strategies. Full article

The emergence of antibiotic-resistant bacteria has resulted in a lack of available drugs that can be used to treat various diseases. Antimicrobial peptides (AMPs) are green and safe antibiotic alternatives. In 2022, an outbreak of an acute diarrheal disease caused by Gram-negative cocci named Neisseria occurred among domestic geese (Anser cygnoides orientalis) in Northeast China. In this study, we analyzed Neisseria S1, which caused diarrhea in geese, and determined whether AMP R7I designed in our laboratory can be used to treat Neisseria infection. This is the first report and isolation of enteropathogenic Neisseria, as well as the first report of Neisseria infection in Anser cygnoides orientalis. Peptide R7I has the capability to counteract Neisseria S1 infection both in vivo and in vitro. R7I induced the release of intracellular contents, leading to the death of Neisseria. Oral treatment of R7I modulated metabolic levels, antioxidant capacity, and immune responses and inhibited inflammation in Neisseria-infected geese. Furthermore, R7I significantly contributed to the recovery of intestinal homeostasis and regulated intestinal function via a signaling pathway related to metabolism in Neisseria infection. During our study of the mechanism of R7I against Neisseria infection, we preliminary found that R7I regulates lipid metabolism disorder and inflammation caused by Neisseria infection through the PPAR signaling pathway. In conclusion, R7I shows a strong ability against Neisseria infection, and it can be used as an oral antibiotic alternative in animal feed. Full article

Background/Objectives: Infant diarrhea is a major global cause of morbidity and mortality. While Bifidobacterium is linked to diarrhea, its preventive effects, underlying mechanisms, and potential synergistic benefits with prebiotics remain unclear. The objective of this study was to explore the efficacy of a synbiotic composed of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) and 2′-fucosyllactose (2′-FL) in alleviating infant diarrhea. Methods: One-week-old C57BL/6J mice were used to construct a model of infant diarrhea via infection with enteropathogenic Escherichia coli (EPEC) O127. Mice were administered BB-12 (10⁸ CFU per mouse), 2′-FL (1 g/kg), or their combination (synbiotic) for three consecutive weeks. Results: Administration of the synbiotic not only markedly improved diarrhea, anxiety-like behavior, colon inflammation, and gut barrier function but also positively reshaped the microbial community. This was achieved through a significant rise in short-chain fatty acid (SCFA)-producing bacteria (e.g., Akkermansia and Paraprevotella), a rise in fecal SCFAs, and a reduction in harmful bacteria such as Escherichia. Conclusions: The synbiotic effectively relieves EPEC-induced infant diarrhea by regulating gut microbiota composition and metabolic functions. These findings highlight its potential as a dietary intervention in infant diarrhea and provide new insights into infant health applications. Full article

Access to microbiologically safe water in preschool educational settings constitutes a pressing public health challenge, particularly in rural areas with deficient infrastructure. Repeated exposure to enteropathogens present in contaminated water has been associated with acute gastrointestinal infections, environmental enteropathy, and disruptions in the intestinal microbiota of young children. Motivated by this concern, the present study evaluates the microbiological quality of water in 32 public preschool facilities in the municipality of Matehuala, San Luis Potosí—18 urban and 14 rural—by analyzing the presence of aerobic mesophilic bacteria (AMB), total coliforms (TC), fecal coliforms (FC), and helminth eggs. The assessment was conducted in accordance with Mexican standards NOM-092-SSA1-1994 and NOM-230-SSA1-2002 and supplemented with the World Health Organization’s guidelines for drinking-water quality. The findings revealed a marked territorial disparity: 100% of rural schools that relied on rooftop water tanks exceeded permissible limits for TC, and 35.7% tested positive for FC. In contrast, all urban schools—supplied through piped water systems—complied with current regulations. Statistical analysis (Mann–Whitney U test, p < 0.05) confirmed significant differences in microbiological contamination based on geographic location and type of water supply. In all FC-positive cases, a lack of sewage infrastructure and inadequate sanitation practices in storage containers were documented. These results demonstrate that formal access to water does not ensure its microbiological safety, particularly in settings with poor structural conditions. The study underscores the urgent need to implement point-of-use water treatment technologies, establish regular microbiological monitoring protocols, and provide training for educational staff in water hygiene practices. Full article

Porcine deltacoronavirus (PDCoV), an emerging enteropathogenic coronavirus, has inflicted substantial economic losses on the global swine industry. While the severity of infectious disease depends on the dynamic interplay between inoculum dose and host response, the molecular mechanism by which PDCoV dose modulates host immunity remains unclear. Hence, we systematically compared the transcriptomic changes in intestinal epithelial cells infected with different doses of PDCoV, and investigated the relationships between inoculum dose, host immune responses, and disease progression. PDCoV replication peaked at 24 h post-infection, and host responses showed a distinct dose-dependent pattern, with high-dose infection inducing more extensive transcriptional remodeling than low-dose infection. Both doses significantly activated the transcription of STAT1 and its downstream interferon-stimulated genes, while high-dose infection additionally triggered a cytokine storm characterized by excessive IL-6 and TNF-α expression. Functional validation demonstrated that STAT1 overexpression markedly inhibited PDCoV infection by enhancing ISRE promoter activity, and overexpression of its downstream ISG15 and MX2 also exerted independent and significant antiviral effects. These findings reveal the biphasic nature of PDCoV dose-dependent regulation of immunopathological mechanisms and identify STAT1 and specific ISGs (ISG15, MX2) as potent antiviral effectors, providing crucial insights into PDCoV pathogenicity and offering promising targets for developing immunomodulatory therapeutics or vaccines to control PDCoV outbreaks in swine. Full article

Escherichia coli contamination in poultry is a significant concern due to its potential to cause foodborne illness. The presence of extraintestinal pathogenic E. coli (ExPEC) strains in chicken carcasses can lead to severe human infections. This study investigates the prevalence, virulence, and antibiotic resistance of E. coli isolates from chicken carcasses processed in both wet market and industrial environments, with a focus on the detection capabilities of MALDI-TOF MS. A total of 119 E. coli isolates were obtained. Only a small proportion (5/119) carried enteropathogenic virulence genes. In contrast, 71.42% (85/119) of the isolates harbored multiple extraintestinal virulence genes. Among these, iucC and sitA, which are associated with systemic infections, were present in 68.24% (58/85) and 43.53% (37/85) of the isolates, respectively. Furthermore, 47.06% (56/119) of the isolates carrying at least two extraintestinal virulence genes were classified as ExPEC. Additionally, 94.6% (54/56) of ExPEC isolates were multidrug resistant (MDR), showing resistance to over three antibiotic classes, raising concerns about the spread of antibiotic resistance. MALDI-TOF MS profiling revealed significant heterogeneity among the ExPEC isolates, with no distinct clustering patterns based on processing environment or sampling site. These findings underscore the public health risks posed by ExPEC in poultry and emphasize the need for improved surveillance, stringent hygiene practices, and responsible antibiotic use in poultry production. Full article

The intestinal health and functionality of animals play pivotal roles in nutrient digestion and absorption, as well as in maintaining defense against pathogenic invasions. These biological processes are modulated by various determinants, including husbandry conditions, dietary composition, and gut microbial ecology. The excessive use of anthropogenic antibiotics may disrupt intestinal microbiota composition, potentially leading to dysbiosis that directly compromises host homeostasis. While Lactobacillus species are recognized for their immunomodulatory properties, their precise mechanisms in regulating host anti-inflammatory gene expression and influencing mucosal layer maturation, particularly regarding E. coli colonization resistance, require further elucidation. To investigate the regulatory mechanisms of Lactobacillus in relation to intestinal architecture and function during E. coli infection, we established a colonic infection model using Bal b/c mice, conducting systematic analyses of intestinal morphology, inflammatory mediator profiles, and microbial community dynamics. Our results demonstrate that Lactobacillus supplementation (Pediococcus acidilactici) effectively mitigated E. coli O78-induced enteritis, with co-administration during infection facilitating the restoration of physiological parameters, including body mass, intestinal histoarchitecture, and microbial metabolic functions. Microbiome profiling revealed that the Lactobacillus intervention significantly elevated Lactococcus abundance while reducing Weissella populations (p < 0.05), concurrently enhancing metabolic pathways related to nutrient assimilation and environmental signal processing (including translation mechanisms, ribosomal biogenesis, amino acid transport metabolism, and energy transduction systems; p < 0.05). Mechanistically, Lactobacillus administration attenuated E. coli-induced intestinal pathology through multiple pathways: downregulating pro-inflammatory cytokine expression (IL-1β, IL-1α, and TNF-α), upregulating epithelial junctional complexes (Occludin, Claudin-1, and ZO-1), and stimulating mucin biosynthesis (MUC1 and MUC2; p < 0.05). These modifications collectively enhanced mucosal barrier integrity and promoted epithelial maturation. This investigation advances our comprehension of microbiota–host crosstalk during enteropathogenic infections under probiotic intervention, offering valuable insights for developing novel nutritional strategies and microbial management protocols in animal husbandry. Full article

Porcine deltacoronavirus (PDCoV) is a newly discovered enteropathogenic coronavirus primarily responsible for diarrhea and mortality in piglets, with the potential to infect humans, thereby posing a significant threat to both human health and the global pig industry. Currently, there is no commercially available live-attenuated vaccine for PDCoV. In this study, an isolated virulent PDCoV strain, DHeB1, was continuously passaged in LLC-PK1 cells for up to 110 passages. The virus growth kinetics in cell culture and complete genome sequences of various passages (F11, F40, F70, F90, and F110) were determined. The results indicated significant increases in virus titers at passages F40 and F90. Sequence analysis revealed that only a few single-nucleotide mutations (some of which resulted in amino acid changes) and one nucleotide insertion were observed throughout successive passages. Notably, the eight and seven amino acid mutations that emerged in F40 and F70, respectively, remained stable in subsequent passages and were predominantly located in the S glycoprotein. The pathogenicity of F11, F40, F70, and F90 was assessed in 5-day-old piglets, revealing markedly reduced clinical symptoms, histopathological lesions, and intestinal PDCoV antigen distributions in piglets inoculated with F70 or F90. Importantly, F90 exhibited little to no virulence in piglets. The immunogenicity of F70, F90, and F110 was further evaluated in weaned piglets, with results indicating that the neutralizing antibody titers induced by F70 and F90 were comparable and significantly higher than those induced by F110. Collectively, these findings suggest that the PDCoV strain DHeB1 has been attenuated and can be used to develop a live-attenuated vaccine against PDCoV. Full article

Background/Objectives: Enterobacteriaceae, including pathogenic Shigella (S.) flexneri and Escherichia (E.) coli, cause severe gastrointestinal infections through toxins like Shiga and Shiga-like toxins. Antibiotic use is often discouraged due to its potential to increase toxin effects or contribute to the development of resistance. The host protease furin is capable of activating several viral glycoproteins and bacterial toxins, thus enhancing pathogen infectivity. Methods: To assess the therapeutic potential of furin inhibitors, cultured epithelial cell models (IPEC-J2 and MDCK) were used. The effects of MI-1851 and MI-2415 were evaluated after short-term (2 h) and long-term (6 h) exposure to S. flexneri, enterohemorrhagic E. coli (EHEC), and enteropathogenic E. coli (EPEC). Cytotoxicity was determined using the CCK-8 assay, and the inflammatory response was assessed by measuring interleukin (IL)-6 and IL-8 levels. Additionally, extracellular hydrogen peroxide production was monitored in IPEC-J2 cells to evaluate the potential alterations in redox status. Results: Infections with EHEC, EPEC, and S. flexneri significantly reduced the viability of epithelial cells after 6 h of incubation. Furin inhibitors MI-1851 and MI-2415 decreased cytotoxicity and compensated for IL-6 and IL-8 overproduction in cells during infection with EHEC and S. flexneri, but not in cells exposed to EPEC. In addition, they alleviated oxidative stress, particularly during S. flexneri addition. Conclusions: The development of new antimicrobial drugs that act via alternative mechanisms and effectively manage life-threatening enterobacterial infections is of key importance. Targeting furin with inhibitors MI-1851 and MI-2415, thus blocking toxin activation, could prevent the development of antimicrobial resistance, reduce the need for antibiotics and enhance overall treatment outcomes. Full article

Escherichia coli (E. coli) is a Gram-negative, commensal/pathogenic bacteria found in human intestines and the natural environment. Pathogenic E. coli is known as extra-intestinal pathogenic E. coli (ExPEC) or intestinal pathogenic E. coli (InPEC). InPEC E. coli strains are separated into six pathogenic groups, known as enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), enteroaggregative (EAEC), enterohaemorrhagic (EHEC), and diffusely adherent (DAEC), that have various virulence factors that cause infection. Virulence factors refer to a combination of distinctive accessory traits that affect a broad range of cellular processes in pathogens. There are two important virulence factors that directly interact with cells to cause diarrhoeal diseases within the intestines: adhesion and colonization factors and exotoxins. Virulence factors are crucial for bacteria to overcome the host’s immune system and result in antibiotic resistance. Antibiotics are used to combat the symptoms and duration of infection by pathogenic E. coli. However, the misuse and overuse of antibiotics have led to the global concern of antibiotic resistance. Currently, the antibiotic colistin is the last-resort drug to fight infection caused by this bacterium. Antibiotic resistance can be achieved in two main ways: horizontal gene transfer and mutation in different genes. The genetic basis for developing antibiotic resistance in E. coli occurs through four mechanisms: limiting drug uptake, modification of the drug target, inactivation of the drug, and active efflux of the drug. These mechanisms use different processes to remove the antibiotic from the bacterial cell or prevent the antibiotic from entering the bacterial cell or binding to targets. This prevents drugs from working effectively, and bacteria can acquire antibiotic resistance. E. coli is classified into different phylogenetic groups (A, B1, B2, D1, D2, E, and clade I). It is a very versatile bacterium that can easily adapt to different environmental factors. The present review gathered information about the pathogenicity, antimicrobial resistance, and phylogenetics of E. coli. These aspects are interconnected; thus, it will provide information on tracking the spread of pathogenic strains and antibiotic resistance genes of different strains using phylogenetics and how antibiotic resistance genes evolve. Understanding genetic variation in E. coli will help in monitoring and controlling outbreaks and in developing novel antibiotics and treatment. The increasing rate of antibiotic resistance, and the ability of E. coli to evolve rapidly, suggest that in-depth research is needed in these areas. Full article

Aeromonas species are enteropathogens that cause gastroenteritis with a unique three-peak infection pattern related to patient age. The contributions of individual Aeromonas species to age-related infections remain unknown. Multi-locus sequence typing (MLST) was performed to determine the species of Aeromonas strains from Australian patients with gastroenteritis. Public database searches were conducted to collect strains of enteric Aeromonas species, identified by either MLST or whole genome sequencing with known patient age. Violin plot analysis was performed to assess Aeromonas infection distribution across patients of different ages. Generalized additive model (GAM) analysis was employed to investigate the relationship between Aeromonas species and patient age. A total of 266 strains of seven Aeromonas species met the selection criteria, which were used for analyses. The violin plots revealed distinct patterns among individual Aeromonas species in relation to patient age. The GAM analyses identified a significant association between Aeromonas species and patient age (p = 0.009). Aeromonas veronii (153 strains) showed the highest probability of infection in most ages, particularly among young adults. Aeromonas caviae (59 strains) is more common in young children and adults over 60 years of age. The probability of infection for Aeromonas hydrophila (34 strains) and Aeromonas dhakensis (9 strains) was generally low, there was a slight increase in individuals aged 50–60 for A. hydrophila and over 60 years for A. dhakensis. These findings provide novel evidence of the varied contributions of different Aeromonas species to human enteric infections related to patient age, offering valuable insights for epidemiology and clinical management. Full article

Bacillus cereus is a Gram-positive pathogen associated with foodborne illnesses and severe non-gastrointestinal infections. Robust tools for accurate gene transcription analysis are essential for studying toxin gene expression dynamics and deciphering the complex regulatory networks orchestrating the expression of toxin and virulence factors. This study aimed to identify reliable reference genes for normalizing reverse transcription quantitative PCR (RT-qPCR) data in toxigenic B. cereus. An emetic and an enteropathogenic strain were used as model organisms to establish a suitable reference gene set to monitor the dynamics of toxin gene transcription. Ten candidate reference genes were evaluated for their expression stability using geNorm, NormFinder, BestKeeper and the ΔCq method, with the final rankings integrated via RefFinder. Among the tested genes, rho, rpoD and recA were identified as the most stable expressed reference genes across all tested conditions. As shown in this proof-of-principle study, the established reference gene set provides a suitable tool to investigate the influence of extrinsic and intrinsic factors on toxin gene transcription. In conclusion, our newly established reference gene set provides a robust basis for studying toxin gene expression in B. cereus and contributes to a better understanding of its pathogenicity and potential strategies to mitigate its harmful effects. Full article

Swine coccidiosis is a widespread disease caused by species of the apicomplexan parasites Eimeria and Cystoisospora. Coccidiosis is a common cause of diarrhea in suckling piglets worldwide that directly reduces piglets’ immunity and increases the risk of infection with other enteropathogens, leading to increased clinical infection and mortality and consequent economic losses in the global pig industry. We searched the available literature to date, including English and Chinese articles, using six electronic bibliographic databases, including PubMed, ScienceDirect, Web of Science, CNKI, VIP Chinese Journal Database, and Wanfang Data. A standard approach for conducting scoping reviews was used to identify studies on the species and distribution of genus Sus coccidia worldwide. A quality assessment was done for each study reviewed and relevant information reported in the identified studies was collated, categorized, and summarized. A total of 149 publications and references were eligible for the final review. The distribution of 18 species of genus Sus coccidia recorded in 63 countries was collated. These included 15 Eimeria and 3 Cystoisospora species. C. suis was found in 48 countries, E. debliecki in 45 countries, E. scabra in 33 countries, E. polita in 31 countries, E. suis in 28 countries, E. perminuta in 26 countries, E. porci in 24 countries, E. neodebliecki and E.spinosa in 21 countries each, E.guevarai in 5 countries, C. almataensis in 4 countries, E. betica in 2 countries, and E. almataensis, E. ibrahimovae, E. residualis, E. szechuanensis, E. yanglingensis, and C. sundarbanensis were each found in only 1 country. Each species was listed according to its scientific name, host name, finding location, and geographical distribution. This review reflects the distribution and infection of genus Sus coccidia worldwide and provides more complete basic information to aid our understanding of the species and geographical distribution of coccidia in the genus Sus. Full article

The research aimed to investigate the perinatal pathology of Alpine ibex (Capra ibex) through the study of four young subjects (at the age of 3 to 4 months) found dead in Valle d’Aosta, a region of northwestern Italy. The carcasses were submitted to necropsy followed by an examination of ecto- and endoparasites (ECP and ENP); samples from the gross lesions (in summary, cutaneous papilloma and crusts, ocular discharge, lobular haemorrhagic areas in the lungs, catarrhal–haemorrhagic enterocolitis) were analysed by bacteriological, histopathological, and biomolecular methods to define the etiological agent. The subjects, with various co-infection patterns, were affected by contagious ecthyma virus (ORFV) (agent of a highly diffusive pustular dermatitis transmissible to small ruminants and humans), Enteropathogenic Escherichia coli (EPEC) (major etiological agent of infantile diarrhoea especially in developing countries), Mycoplasma conjunctivae (MC) (cause of an ocular infection common to goats and sheep), various ECP (ticks and keds) and ENP (lung and intestinal nematodes, and coccidia). This study emphasises the potential role of the Alpine ibex in the transmission of infectious diseases to other animals such as to humans and, secondly, the need to apply diversified analytical approaches, with the commitment of various specialistic skills, in order to define, in detail, the various and frequently overlapping causes that led a free-ranging animal to the death. Full article