Search Results (130)

The emergence of colistin-resistant Escherichia coli (E. coli) in livestock poses a major public health concern due to its zoonotic potential and multidrug resistance (MDR). The study aimed to detect mobilized colistin resistance genes (mcr-1 to mcr-9) in E. coli isolates, along with characterizing their antimicrobial susceptibility, resistance genes, virulence genes, and whole genome sequencing. We investigated E. coli contamination in a swine slaughterhouse in Nakhon Si Thammarat Province, Thailand. A total of 200 fecal samples were collected and screened for E. coli using selective media supplemented with colistin. A total of 200 fecal samples were collected from a swine slaughterhouse and screened for E. coli using selective media supplemented with colistin. Presumptive E. coli isolates were confirmed by PCR, followed by molecular detection of mcr-1 to mcr-9 genes. Antimicrobial susceptibility testing was performed using the disk diffusion method. Selected isolates were further analyzed for additional antimicrobial resistance genes and virulence associated genes by PCR. Whole genome sequencing was conducted on representative isolates exhibiting high levels of antimicrobial resistance. Our results showed that out of 200 fecal samples, 124 presumptive E. coli isolates were recovered from a swine slaughterhouse using selective media containing colistin. PCR confirmation identified 112 isolates (90.32%) as E. coli. Molecular detection of mobilized colistin resistance (mcr) genes (82 isolates, 73.21%) demonstrated that mcr-1 (50.89%) was the most prevalent, followed by mcr-9 (25.89%) and mcr-3 (24.11%). Overall, the 82 mcr E. coli isolates showed the highest level of resistance to ampicillin (97.56%), followed by tetracycline (95.12%), piperacillin (73.17%), and chloramphenicol (65.85%). For non-mcr E. coli isolates, the highest resistance percentage was observed for ampicillin (96.67%), followed by piperacillin (80%) and tetracycline (73.33%). Among the isolates, 75% exhibited MDR phenotypes, showing 22 distinct resistance profiles. The most common MDR pattern was AMP-PIP-TE-C-S (12.5%). Additional antimicrobial resistance genes, including aadA, ampC, and bla_TEM, were detected in over 60% of a subset of 30 tested isolates. The virulence gene analysis revealed that eae (74.10%), associated with enteropathogenic E. coli (EPEC), was the predominant pathotype. Whole genome sequencing of five selected isolates confirmed the presence of multiple antimicrobial resistance and virulence determinants. In conclusion, this study reveals a high prevalence of MDR E. coli harboring colistin resistance genes (mcr-1 to mcr-9) in a swine slaughterhouse in southern Thailand. The findings highlight the potential risk of zoonotic transmission of antimicrobial resistant E. coli through the food production chain and emphasize the importance of continuous genomic surveillance and prudent antimicrobial use in livestock production systems. Full article

This pilot study investigated the presence of methicillin-resistant Staphylococcus aureus (MRSA) and third-generation cephalosporin-resistant (3GC-R) Enterobacterales in conventionally kept domestic pigs and their environment across four districts in Rwanda. A total of 114 swabs (nasal, rectal, manure, dust) from 29 farms were collected and processed to isolate resistant bacteria. Thirty-two 3GC-R Enterobacterales were detected. Escherichia coli predominantly harboring bla_CTX-M group 1 β-lactamase genes, alongside Klebsiella pneumoniae isolates, all displaying extended-spectrum β-lactamase (ESBL) phenotypes. Four MRSA isolates, all belonging to clonal complex 398 and SCCmec type IV, the typical livestock MRSA, were recovered from nasal and environmental samples. Multidrug resistance was frequently observed. The co-occurrence of β-lactamase genes, non-β-lactam resistance genes, and virulence factors such as fimH and loci associated with extraintestinal pathogenic and enteropathogenic E. coli. The detection of both MRSA and 3GC-R Enterobacterales in the present study indicates pigs and their farm environments as reservoirs of WHO priority pathogens in Rwanda, highlighting a potential public health risk in the context of extensive human–animal–environment interaction. These findings emphasize the urgent need for integrated One Health surveillance and comprehensive AMR control strategies addressing both animal and environmental reservoirs to support Rwanda’s National Action Plan on Antimicrobial Resistance. Full article

Objectives: This observational and cross-sectional study investigated differential associations between entero-invasive and non-entero-invasive enteric pathogens and HIV infection, considering socioeconomic, clinical and immunological aspects. In a Ghanaian population with a high prevalence of enteric pathogens, stool samples from people living with HIV (PLWH) were screened for Salmonella spp., Shigella spp./EIEC (enteroinvasive Escherichia coli), and Campylobacter jejuni as entero-invasive bacteria, for enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enteroaggregative E. coli (EAEC) as non-entero-invasive bacteria. Arcobacter butzleri, with uncertain enteropathogenicity, was also included. Methods: Stool samples from PLWH (with and without antiretroviral therapy) and HIV-negative controls were analyzed by real-time PCR for the presence and quantity of the selected enteropathogens. Results were correlated with socioeconomic, clinical, and immunological parameters. Results: The presence of Shigella spp. /EIEC in stool was both qualitatively and quantitatively associated with reduced CD4+ T lymphocyte counts and was qualitatively associated with clinically apparent diarrhea. EAEC showed a weak positive association with HIV infection, supported by a negative correlation between EAEC DNA quantity and CD4+ T lymphocyte counts. EPEC colonization was associated with HIV negativity, higher CD4+ T lymphocyte counts, and lower socioeconomic status. Abundance of Salmonella enterica was associated with clinically apparent diarrhea. Conclusions: This explorative, hypothesis-forming study suggests species- or pathovar-specific associations between enteric bacterial pathogens and HIV-related immunosuppression. Observed relationships with clinically apparent diarrhea largely align with findings from sub-Saharan African children, except for a more pronounced association between diarrhea and Salmonella in this cohort. Full article

Background: Escherichia coli strains associated with poultry are increasingly recognized as reservoirs of both virulence and resistance genes, posing significant zoonotic risks throughout the food production chain. However, the genotypic architecture and pathogenic potential of isolates from large-scale turkey farms remain under characterized, particularly in the context of extended-spectrum β-lactamase (ESBL) production. Methods: A total of 160 ESBL-producing E. coli isolates were collected from healthy turkeys on intensive Hungarian farms. Whole genome sequencing (WGS) was performed to characterize virulence factors. Functional annotation included screening for fimbrial adhesins, iron acquisition systems, secretion pathways, and autotransporter toxins, using VirulenceFinder and Prodigal-based genome annotations. Data analysis included assembly quality control with QUAST and BUSCO, and comprehensive virulome profiling. Results: The isolates exhibited a functionally diverse virulence profile encompassing classical ExPEC-associated colonization factors (type I, P, S fimbriae; curli; ECP), multiple iron acquisition systems (enterobactin, salmochelin, aerobactin, yersiniabactin, and heme uptake), and key secretion systems (LEE-associated T3SS and T2SS). Genetic hallmarks of avian pathogenic E. coli (APEC), uropathogenic pathogenic E. coli (UPEC), and enteropathogenic E. coli (EPEC) pathotypes co-occurred in 44% of the isolates, indicating a mosaic virulence landscape. Notably, serine protease autotransporters of Enterobacteriaceae (SPATE) toxins (Vat, Pic) and ColV-type plasmid-associated modules were frequently detected. All isolates were confirmed by ESBL producers, highlighting their antimicrobial resistance potential. Conclusions: This study reveals that E. coli strains isolated from turkeys possess a complex, host-adapted virulence repertoire capable of supporting both enteric and extraintestinal infections. The co-occurence of APEC-, UPEC-, and EPEC-like traits—combined with ESBL production—underscores their One Health relevance. These findings support the need for host-specific surveillance, functional validation, and integrative control strategies in poultry systems. Full article

Background: Enteropathogenic Escherichia coli (EPEC) disrupts intestinal barrier integrity by adhering to epithelial cells, leading to diarrhea, impaired nutrient absorption, oxidative stress, and intestinal inflammation in young animals. This study aimed to isolate and characterize a neutral exopolysaccharide (EPS-T1) from Enterococcus faecium HDRsEf1, evaluate its functional activities in vitro, and assess its protective effects against EPEC-induced enteritis in vivo. Results: EPS-T1, with a molecular weight of 81.21 ± 1.28 kDa, was mainly composed of glucose, galactose, rhamnose, and mannose, and exhibited a porous, sheet structure with relatively high thermal stability. In vitro, EPS-T1 (200 μg/mL) significantly inhibited EPEC growth and biofilm formation, reduced bacterial adhesion to intestinal epithelial cells, and exhibited broad-spectrum free radical scavenging activity. In vivo, EPS-T1 treatment alleviated EPEC-induced weight loss and intestinal tissue damage, reduced the intestinal EPEC load, downregulated pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), upregulated the anti-inflammatory cytokine IL-10, and improved serum antioxidant indices (T-AOC, SOD, and GSH-PX) while decreasing MDA levels. Conclusions: These results demonstrate that EPS-T1 derived from Enterococcus effectively mitigates EPEC-induced intestinal inflammation and oxidative stress, highlighting its potential as an immunobiotic functional candidate. Full article

Melia azedarach L. (Meliaceae) exhibits potential as a source of bioactive antibacterial compounds. In this study, the effect of solvent polarity on ultrasound-assisted extraction of M. azedarach leaves and twigs was evaluated in relation to their phytochemical composition and antibacterial activity against both non-resistant and multidrug-resistant bacteria. The results showed that solvent polarity significantly affected the extraction yield, with methanol and water producing yields above 10%. The methanol extracts of twigs and leaves exhibited the strongest antibacterial activity, showing greater potency against Escherichia coli than Bacillus subtilis. Consistent with these findings, the methanol extracts inhibited the growth of multidrug-resistant enteropathogenic E. coli K1-1, resulting in inhibition zone diameters of 10.93 mm (leaf) and 7.73 mm (twig). Furthermore, the methanol extract contained the highest levels of phenolic, flavonoid, and hydroxyl-rich compounds, which were associated with its antibacterial properties. In silico analysis further revealed that isofucosterol, meliasenin, and melianone exhibited strong predicted binding affinities to key antibacterial proteins, particularly those involved in multidrug-resistant bacterial mechanisms. Full article

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

Background: Diarrheagenic Escherichia coli (DEC) remains relevant to public health and agri-food chains. The context in Brazil, as a major food producer and exporter, reinforces the need for genomic surveillance. Objective: We aimed to characterize Brazilian diffusely adhering (DAEC), enteropathogenic (EPEC), and Shiga toxin-producing E. coli (STEC) sequences in silico across O-serogroups, in addition to sequence-type (ST), virulence, resistome, and phylogenomic relationships. Methodology: We retrieved 973 genomes assigned to Brazil from NCBI Pathogen Detection Database and performed virtual-PCR screening for key DEC-genes. We then typed O-serogroups (ABRicate/EcOH), Multi-Locus Sequencing Type (MLST), virulome (Ecoli_VF), resistome (ResFinder), and characterized stx genes. Results: DEC represented 18.7% of genomes, driven primarily by EPEC. In EPEC, the eae β-1 subtype was most common; we detected, for the first time in Brazilian sequences, ξ-eae subtype and ST583/ST301. Seventy-eight percent of DAEC isolates were multidrug-resistant (MDR), and two ST were newly reported in the country (ST2141/ST500). In STEC, O157 formed a largely susceptible clade with uniform eae γ-1, whereas 57% of non-O157 were MDR. New STs (ST32/ST1804) were observed, and three genomes were closely related to international isolates. Conclusions: Despite the low DEC representation in the dataset, new STs and eae subtypes were detected in Brazil. Also, MDR in DAEC and non-O157 STEC reinforces the need for antimicrobial-resistance genomic surveillance. Full article

Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) are E. coli pathovars of particular relevance to infant health. While the intestinal tract of humans and animals constitutes their primary habitat, these bacteria can also persist in natural environments such as sand. The aim of this study was to evaluate the persistence of STEC and EPEC strains in sand microcosms under controlled conditions of heat and desiccation in order to estimate their viability in this matrix and provide evidence regarding the potential risks associated with the use of sandboxes in public spaces. The study included STEC strains belonging to clinically important serotypes (O26:H11, O103:H2, O111:H8, O121:H19, O145:NM, O157:H7 and O174:H28), animal-derived EPEC strains, and a non-pathogenic E. coli strain (NCTC 12900). The strains were inoculated into sterile sand microcosms and maintained at 37 °C. Death curves, persistence in the matrix, presence of virulence genes, and ability to produce biofilm were evaluated. The death and persistence curves varied by serotype; some strains remained viable in the viable but non-culturable state for extended periods. All strains retained their virulence-associated genetic markers throughout the assays. None of the STEC strains was classified as a biofilm producer under the experimental conditions, whereas the two EPEC strains were identified as weak and moderate biofilm producers. However, no association was found between biofilm formation and persistence in the matrix. The findings provide an initial approach and provide relevant evidence of the capacity of STEC and EPEC strains to survive in sand, which could represent a potential risk in recreational environments. 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

Background/Objectives: Increasing levels of antimicrobial resistance (AMR) have recently been observed at the human–domestic animal–wildlife interface. Wild birds have been identified as carriers of antimicrobial-resistant bacteria and serve as excellent biomarkers for epidemiological studies. This study assessed the current AMR presence in Eastern Spain’s commensal Escherichia coli isolated from free-ranging Bonelli’s eagles (Aquila fasciata). Methods: Nestlings and their nests were intensively sampled between 2022 and 2024 to determine their AMR profile and characterize E. coli. AMR testing was conducted using the broth microdilution method, following the European Committee on Antimicrobial Susceptibility Testing guidelines. Additionally, the presence of eaeA (intimin gene) and stx-1 and stx-2 (shiga toxins) was analyzed by real-time PCR to classify E. coli strains into enteropathogenic (EPEC) and Shiga-toxigenic (STEC) pathotypes. Results: Of all E. coli isolates, 41.7% were resistant to at least one antimicrobial, and 30% were multidrug-resistant. Only two strains were classified as EPEC and none as STEC. The highest resistance rates were observed for amoxicillin and tetracycline (19.6% each). Alarmingly, resistance to colistin and meropenem, last-resort antibiotics in human medicine, was also detected. Conclusions: Although the mechanisms of resistance acquisition remain unclear, transmission is likely to occur through the food chain, with synanthropic prey acting as intermediary vectors. These results highlight the role of Bonelli’s eagles as essential sentinels of environmental AMR dissemination, even in remote ecosystems. Strengthening One Health-based surveillance is necessary to address AMR’s ecological and public health risks in wildlife. Full article

Gamma-aminobutyric acid (GABA) is a non-protein amino acid playing a significant role in the central nervous system and the gut–brain axis. This study investigated the potential to produce GABA by lactic acid bacteria (LAB) isolated from different varieties of organic tomatoes. The isolated LAB were taxonomically identified by 16S rRNA gene sequencing, the presence of the gadB gene (glutamate decarboxylase) was detected, and GABA production was quantified using HPLC. Levilactobacillus brevis CRAI showed the highest GABA production under optimised fermentation conditions with 4% monosodium glutamate (MSG). The genome sequencing of L. brevis CRAI revealed the presence of gadA and gadB isoforms and assessed the strain’s safety profile. The gene expression analysis revealed that the gadA and gadB genes were upregulated in the presence of 4% MSG. The probiotic potential of L. brevis CRAI was also assessed by functional assays. The strain showed strong antimicrobial activity against representative enteropathogens, i.e., Escherichia coli ETEC, Salmonella choleraesuis, and Yersinia enterocolitica, and anti-inflammatory effect, reducing nitric oxide production in LPS-stimulated RAW264.7 macrophages. In addition, its ability to adhere to intestinal epithelial Caco-2 cells was demonstrated. These results highlight L. brevis CRAI as a promising candidate for the development of GABA-enriched functional foods or probiotic supplements with the perspective to modulate the gut-brain axis. Full article

Acute diarrhoeal disease caused by antibiotic-resistant diarrhoeagenic bacteria is a significant global public health issue, particularly in low- and middle-income countries. This study provides the first molecular characterisation of antimicrobial resistance profiles, including the detection of CTX-M-15 and CTX-M-55 extended-spectrum beta-lactamases (ESBLs), among diarrhoeagenic Enterobacterales in Bioko Island, Equatorial Guinea, offering novel epidemiological insights into an understudied region. This study investigated the antibiotic resistance profiles of pathogenic bacteria isolated from diarrhoeal samples on Bioko Island. A total of 153 clinical isolates were collected between 1 February and 30 May 2014, and antimicrobial susceptibility testing was performed at Loeri Comba Polyclinic (Malabo) using the Kirby–Bauer method. The molecular characterisation of β-lactamase-associated genes was performed on different isolates of diarrhoeagenic pathotypes—144 Escherichia coli, 7 Salmonella enterica, and 2 Shigella flexneri—at the National Centre for Microbiology (Majadahonda, Spain). High resistance rates were detected against ampicillin (98%), tetracycline (93.5%), sulfonamides (94.8%), sulfamethoxazole–trimethoprim (88.2%), and cefotaxime (78.8%), while moderate rates of resistance were noted for ciprofloxacin (26.7%), and all isolates remained susceptible to imipenem. Of the isolates, 107 (69.9%) produced either single or multiple β-lactamases. Among these, 73 (68.2%) harbored classical β-lactamases, specifically TEM and OXA-1 types, representing 47.7% of the total sample. Additionally, 34 (31.8%) of the isolates were identified as producers of extended-spectrum β-lactamases (ESBLs), specifically CTX-M enzymes. Sequencing identified CTX-M-15 and CTX-M-55 variants. The predominant ESBL-producing bacteria were enteroaggregative Escherichia coli (56.2%), followed by enteropathogenic and enterotoxigenic E. coli. These findings confirm the circulation of multidrug-resistant diarrhoeagenic Enterobacterales in Equatorial Guinea, raising concerns about limited treatment options due to widespread resistance to multiple antibiotic classes, including third-generation cephalosporins and quinolones. The most important conclusion drawn from this study is that a high percentage of diarrhoeagenic bacteria have an antibiotic resistance and multi-resistance profile, especially to beta-lactams and other groups of antibiotics such as tetracyclines and sulphonamides. There is also a moderate prevalence of isolates carrying ESBLs on Bioko Island, Equatorial Guinea, which could indicate the inappropriate use of antimicrobials. 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