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With increasing urbanization and industrialization, the prevalence of inflammatory bowel diseases (IBDs) has steadily been rising over the past two decades. IBD involves flares of gastrointestinal (GI) inflammation accompanied by microbiota perturbations. However, microbial mechanisms that trigger such flares remain elusive. Here, we analyzed the association of the emerging pathogen atypical enteropathogenic E. coli (aEPEC) with IBD disease activity. The presence of diarrheagenic E. coli was assessed in stool samples from 630 IBD patients and 234 age- and sex-matched controls without GI symptoms. Microbiota was analyzed with 16S ribosomal RNA gene amplicon sequencing, and 57 clinical aEPEC isolates were subjected to whole-genome sequencing and in vitro pathogenicity experiments including biofilm formation, epithelial barrier function and the ability to induce pro-inflammatory signaling. The presence of aEPEC correlated with laboratory, clinical and endoscopic disease activity in ulcerative colitis (UC), as well as microbiota dysbiosis. In vitro, aEPEC strains induce epithelial p21-activated kinases, disrupt the epithelial barrier and display potent biofilm formation. The effector proteins espV and espG2 distinguish aEPEC cultured from UC and Crohn’s disease patients, respectively. EspV-positive aEPEC harbor more virulence factors and have a higher pro-inflammatory potential, which is counteracted by 5-ASA. aEPEC may tip a fragile immune–microbiota homeostasis and thereby contribute to flares in UC. aEPEC isolates from UC patients display properties to disrupt the epithelial barrier and to induce pro-inflammatory signaling in vitro.

Enteropathogenic Escherichia coli (EPEC) uses a type three secretion system to inject effector proteins into host intestinal epithelial cells, causing diarrhea. EPEC induces the formation of pedestals underlying attached bacteria, disrupts tight junction (TJ) structure and function, and alters apico-basal polarity by redistributing the polarity proteins Crb3 and Pals1, although the mechanisms are unknown. Here we investigate the temporal relationship of PAR polarity complex and TJ disruption following EPEC infection. EPEC recruits active aPKCζ, a PAR polarity protein, to actin within pedestals and at the plasma membrane prior to disrupting TJ. The EPEC effector EspF binds the endocytic protein sorting nexin 9 (SNX9). This interaction impacts actin pedestal organization, recruitment of active aPKCζ to actin at cell–cell borders, endocytosis of JAM-A S285 and occludin, and TJ barrier function. Collectively, data presented herein support the hypothesis that EPEC-induced perturbation of TJ is a downstream effect of disruption of the PAR complex and that EspF binding to SNX9 contributes to this phenotype. aPKCζ phosphorylates polarity and TJ proteins and participates in actin dynamics. Therefore, the early recruitment of aPKCζ to EPEC pedestals and increased interaction with actin at the membrane may destabilize polarity complexes ultimately resulting in perturbation of TJ. [ABSTRACT FROM AUTHOR]

Diarrheagenic E. coli (DEC) are one of the most common causes for diarrhea worldwide, especially in children. We evaluated the rapid RIDA ® GENE (RG) real-time multiplex PCR assays (R-Biopharm, Darmstadt, Germany) for the detection of the most important diarrheagenic E. coli . Three hundred fifteen liquid or non-formed stool specimens were examined. The results of the RG multiplex assays were compared to specific PCR methods. The sensitivity and specificity of the RG PCRs were as follows, 100%/100% for the detection of EHEC, 96.3% and 99% for EPEC, 100% and 100% for the detection of EAEC, ETEC and EIEC, respectively. Overall, the RG real-time PCR system for the detection of DEC tested in this study provided reliable and rapid results and shows the ability as a useful addendum for the detection of diarrheagenic E. coli in the medical laboratory. [ABSTRACT FROM AUTHOR]

Aim: This study aims to investigate the prevalence of intestinal pathogenic Escherichia coli (InPEC) in healthy pig-related samples and evaluate the potential virulence of the InPEC strains., Methods and Results: A multiplex PCR method was established to identify different pathotypes of InPEC. A total of 800 rectal swab samples and 296 pork samples were collected from pig farms and slaughterhouses in Hubei province, China. From these samples, a total of 21 InPEC strains were isolated, including 19 enteropathogenic E. coli (EPEC) and 2 shiga toxin-producing E. coli (STEC) strains. By whole-genome sequencing and in silico typing, it was shown that the sequence types and serotypes were diverse among the strains. Antimicrobial susceptibility assays showed that 90.48% of the strains were multi-drug resistant. The virulence of the strains was first evaluated using the Galleria mellonella larvae model, which showed that most of the strains possessed medium to high pathogenicity. A moderately virulent EPEC isolate was further selected to characterize its pathogenicity using a mouse model, which suggested that it could cause significant diarrhea. Bioluminescence imaging (BLI) was then used to investigate the colonization dynamics of this EPEC isolate, which showed that the EPEC strain could colonize the mouse cecum for up to 5 days., (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)

It was reported that probiotics could maintain the balance of intestinal microfloral and increase intestinal immune system. The objective of this study was to analyze the influence of indigenous probiotic Lactobacillus fermentum and Lactobacillus plantarum on the morphological profile of small intestine of Enteropathogenic E. coli (EPEC)- infected rats. This study was done from August to November 2011 at Bogor Agricultural University. A total of 90 male rats Sprague Dawley were used in this study. They were devided into 6 groups; negative control (A), Lactobacillus plantarum treated (B), Lactobacillus fermentum treated (C), Lactobacillus plantarum and EPEC treated (D), Lactobacillus fermentum and EPEC treated (E), and EPEC infected group (F). The treatments were done for 21 days. Small intestine tissues were processed using paraffin embedding standard method and stained with haematoxylin eosin. The data were analyzed using analysis of variance (ANOVA). The results showed that L. fermentum and L. plantarum treatments decreased percentage of small intenstine villi damage (14 to 62%) and increased the thickness of small intestine mucosa (14 to 29%). In conclusions, treatment of indigenous probiotic L. fermentum and L. plantarum increase the health of small intestine. L. fermentum give better effect in inhibiting the damage of small intestine of rats, which under EPEC infection.

The histopathological alterations in the intestinal tract of recently weaned rabbits with experimental and spontaneous Eschercihia coli (O15:H-) infection were followed. A considerable shortening and thickening of well epithelized intestinal villi were observed, whose tips, after a Warthin-Starry staining, were profusely colonized with coliform bacteria. The observed pathological pattern was a permanent finding in such infections and could be used as a pathognomic feature in the differential diagnosis of spontaneous diarrhoeic syndromes. The adhesion of colibacteria to enterocytes, together with the data from the bacteriological studies (isolation, identification, determination of the O-serogroup affiliation and the biochemical behaviour) allowed the assignment of isolates to the group of enteropathogenic E. coli (EPEC). Only when required, more detailed diagnostical procedures as PCR, could be performed.

Immunity development known as one of effective ways in avoiding infection. Antibacterial agent product isolated from Lactobacillus acidophillus has been reported can activate T lymphocyte as part of adaptive immunity. This experimental study aimed at investigation of lactic acid and bacteriocins filtrate from L. acidophillus in modulating phagocytosis activity of human macrophages infected by enteropathogenic Escherichia coli (EPEC). Each of human macrophages culture was supplemented with lactic acid and bacteriocins filtrate at concentration of 3.125, 6.25, and 12.5 µg mL-1 as well as control without filtrate addition and incubated for 24 h. Macrophages culture was then infected with EPEC for 30 minutes and was microscopically observed after being stained by Giemsa. Percentage of phagocytosis activity was gained from active macrophages in 100 observed cells. Macrophages cultures supplemented with bacteriocins filtrate showed augmented phagocytosis activity while cultures supplemented with lactic acid filtrate showed decreased phagocytosis activity. ANOVA analysis showed significant difference in phagocytosis activity of macrophage cultures supplemented with lactic acid (p=0,038) and bacteriocins (p=0,016 and 0,023). Tukey HSD analysis for phagocytosis activity of macrophage cultures supplemented by bacteriocins, each group of treatment showed significant difference againts control. In conclusion, lactic acid from L.acidophillus has no effect in modulation of macrophages phagocytosis activity while bacteriocins can improve phagocytic activity. Bacteriocins from L. acidophillus then can be suggested to have a role as immunomodulator.

Enteropathogenic E. coli causes attaching and effacing (A/E) intestinal lesions. The genes involved in the formation of A/E lesions are encoded within a chromosomal island comprising of five major operons, LEE1-5. The global regulator H-NS represses the expression of these operons. Ler, a H-NS homologue, counteracts the H-NS-mediated repression. Using a novel genetic approach, we identified the amino acid residues in Ler that are involved in the interaction with H-NS: I20 and L23 in the C-terminal portion of α-helix 3, and I42 in the following unstructured linker region. [ABSTRACT FROM AUTHOR]

Escherichia coli of the O157 serogroup are comprised of a diverse collection of more than 100 O157:non-H7 serotypes that are found in the environment, animal reservoir and infected patients and some have been linked to severe outbreaks of human disease. Among these, the enteropathogenic E. coli O157:non-H7 serotypes carry virulence factors that are hallmarks of enterohemorrhagic E. coli, such as causing attaching and effacing lesions during human gastrointestinal tract infections. Given the shared virulence gene pool between O157:H7 and O157:non-H7 serotypes, our objective was to examine the prevalence of virulence traits of O157:non-H7 serotypes within and across their H-serotype and when compared to other E. coli pathovars. We sequenced six O157:non-H7 genomes complemented by four genomes from public repositories in an effort to determine their virulence state and genetic relatedness to the highly pathogenic enterohemorrhagic O157:H7 lineage and its ancestral O55:H7 serotype. Whole-genome-based phylogenomic analysis and molecular typing is indicative of a non-monophyletic origin of the heterogeneous O157:non-H7 serotypes that are only distantly related to the O157:H7 serotype. The availability of multiple genomes enables robust phylogenomic placement of these strains into their evolutionary context, and the assessment of the pathogenic potential of the O157:non-H7 strains in causing human disease. [ABSTRACT FROM AUTHOR]

Abstract: Enteropathogenic Escherichia coli (EPEC) represents a major cause of lethal diarrhea in young mammals. Although the pathogenicity mechanisms of EPEC are now well understood, the intrinsic and environmental factors that control the expression of EPEC virulence remain largely unknown. In the rabbit, suckling reduces pups’ sensitivity to EPEC infection. Hence, we have hypothesized that uncharacterized factors present in doe milk may mediate this protection. Medium chain fatty acids (MCFA), known to possess antimicrobial properties, are highly abundant in doe milk. We demonstrate that caprylic acid exhibits a clear bacteriostatic effect in vitro against the rabbit EPEC strain E22 (O103:H2:K-), in a dose-dependent manner. In vivo, the dietary inclusion of triglycerides of MCFA did not however reduce the sensitivity of young rabbits challenged with this EPEC strain. The mortality and fecal excretion of EPEC were not reduced, and the bacterial adhesion to ileum was not inhibited. Amount of MCFA reaching the ileal level might have been too low and/or their association to other milk antimicrobials may have been required to observe a positive effect on disease evolution in a context of a highly virulent challenge. [Copyright &y& Elsevier]

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli O157:H7 (EHEC) form characteristic lesions on infected mammalian cells called actin pedestals. Each of these two pathogens injects its own translocated intimin receptor (Tir) molecule into the plasma membranes of host cells. Interaction of translocated Tir with the bacterial outer membrane protein intimin is required to trigger the assembly of actin into focused pedestals beneath bound bacteria. Despite similarities between the Tir molecules and the host components that associate with pedestals, recent work indicates that EPEC and EHEC Tir are not functionally interchangeable. For EPEC, Tir-mediated binding of Nck, a host adaptor protein implicated in actin signaling, is both necessary and sufficient to initiate actin assembly. In contrast, for EHEC, pedestals are formed independently of Nck, and require translocation of bacterial factors in addition to Tir to trigger actin signaling. [Copyright &y& Elsevier]

Shiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) make up an important group of pathogens causing major animal and public health concerns worldwide. The aim of this study was to determine the prevalence of different pathotypes of E. coli in captive wildlife. We analyzed 314 fresh fecal samples from captive wildlife, 30 stool swabs from animal caretakers, and 26 feed and water samples collected from various zoological gardens and enclosures in India for the isolation of E. coli, followed by pathotyping by multiplex PCR. The overall occurrence rate of E. coli was 74.05% (274/370). The 274 E. coli isolates were pathotyped by multiplex PCR targeting 6 genes. Of them, 5.83% were pathotyped as EPEC, 4.74% as STEC, and 1.09% as ETEC. The 16S rRNA genes from the selected isolates were amplified, sequenced, and a phylogenetic tree was constructed. The phylogenetic tree exhibited indiscriminate genetic profiling and some isolates from captive wild animals had 100% genetic identity with isolates from caretakers, suggesting that captive wildlife may serve as a reservoir for infection in humans and vice-versa. The present study demonstrates for the first time the prevalence of these E. coli pathotypes in captive wildlife in India. Our study suggests that atypical EPEC strains are more frequent than typical EPEC strains in captive wildlife. Discovering the implications of the prevalence of these pathotypes in wildlife conservation is a challenging topic to be addressed by further investigations.