Search Results (219)

Introduction: Haemolytic Escherichia coli (E. coli) is commonly associated with enteric disease in pigs and is frequently used as a phenotypic marker for enterotoxigenic E. coli (ETEC). This study aimed to characterise the resistance and virulence profiles of haemolytic E. coli isolated from Colombian pig farms. Methods: A total of 367 faecal samples from sows and pigs across all production stages were collected and analysed for the presence of haemolytic E. coli. Resistance and virulence genes associated with ETEC was detected by multiplex PCR, and antimicrobial susceptibility profiles were determined using broth microdilution and disc diffusion. Results: Haemolytic E. coli were identified in 40.3% of samples (n = 148 non-duplicate isolates), with the highest prevalence observed in growing piglets (47.1%). ETEC occurred in 5.4% of isolates. All isolates exhibited resistance to at least three antimicrobial classes (MDR), with high levels of resistance to tetracycline (98.0%), neomycin (97.3%), chloramphenicol (95.9%), sulfamethoxazole (93.9%), trimethoprim (91.9%), ampicillin (91.9%), nalidixic acid (82.4%), and ciprofloxacin (79.7%). Colistin resistance was observed in 5.4% of isolates, mediated by mcr1 or mcr3, while cefotaxime resistance (8.8%) was extensively associated with blaCTX-M. Conclusions: These findings reveal a concerning burden of MDR E. coli in Colombia’s pig-producing regions and indicate that haemolysis alone is a poor indicator of ETEC. Integrating farm-level antimicrobial use data with genomic analyses will be essential to identify drivers of AMR and guide effective stewardship in the Colombian pig industry. Full article

Transmissible gastroenteritis (TGE), caused by the TGE virus (TGEV), is a highly contagious enteric disease characterized by vomiting, dehydration, and watery diarrhea. It mainly endangers piglets within two weeks of age, with a 100% mortality rate, inflicting severe economic losses on the global swine industry. Since enteric tropism of the virus and mucosa serves as the first line of defense against viral invasion, an oral vaccine inducing sufficient secretory immunoglobulin A (SIgA) antibodies in animals should be developed. Being a generally recognized as safe (GRAS) microorganism, Bacillus subtilis can form endospores under extreme environmental conditions, which confer resistance to the hostile gastric environment and have been widely employed as delivery vehicles for oral vaccines owing to their immunoadjuvant activity and non-specific antidiarrheal effects. In this study, the AD antigenic epitope of the TGEV S protein was selected as the immunogen. The mature peptide of the B subunit of the heat-labile enterotoxin from enterotoxigenic Escherichia coli served as a mucosal adjuvant, and B. subtilis WB800N was used as the delivery host to construct the recombinant strain pHT43-LTB-AD/WB800N. After confirming the successful expression of the target protein, oral immunization was performed using mice as a model. The results demonstrated that this recombinant strain induced robust mucosal, humoral, and cellular immunity, along with considerable levels of neutralizing antibodies. These findings indicate that recombinant B. subtilis could serve as an oral vaccine candidate to combat TGEV infections. Full article

Enterotoxigenic Escherichia coli (ETEC)-induced neonatal calf diarrhea (NCD) causes significant economic losses to the cattle industry; therefore, understanding its antibiotic resistance is crucial for developing targeted prevention and treatment strategies. However, reports on antibiotic resistance in bovine ETEC are currently limited. This study conducted whole-genome sequencing (WGS) and antimicrobial susceptibility testing on ETEC F5- and F5-F41-positive strains isolated from neonatal calf diarrhea samples in Inner Mongolia, China. The results showed that both ETEC F5- and ETEC F5-F41-positive strains are multidrug-resistant, containing ceftriaxone (CRO), ceftazidime (CAZ)) and ciprofloxacin (CIP), which are listed as the highest priority critically important antimicrobial (HP-CIAs) by the World Health Organization (WHO). Combined analysis using the Comprehensive Antibiotic Resistance Database (CARD) and ResFinder 4.1 predictive analysis revealed that the chromosomes and plasmids of the 2 ETEC-positive strains contained 11 classes of antibiotic resistance genes, with the top 3 categories in terms of the number of resistance genes being aminoglycosides, β-lactamases, and chloramphenicols. In addition, various bacterial efflux pumps, including RND, MFS, SMR, and the ABC efflux pump family, were detected. A total of 74 antimicrobial resistance genes were identified in the 2 strains, belonging to 5 categories of drug resistance mechanisms; the antimicrobial resistance phenotype was consistent with the genotype. This study provides a reference for the prevention and treatment of diarrhea caused by ETEC. Full article

The objective of this study was to investigate the effects of replacing fishmeal with H. illucens larval meal on the colonic immune homeostasis in weaned piglets in enterotoxigenic Escherichia coli (ETEC)-challenged pig housing. Seventy-two weaned piglets, aged 28 days, were randomly divided into three groups for dietary treatment: the basal diet (negative control, NC), the positive control diet (PC) supplemented with 1445 mg zinc/kg zinc oxide in the basal diet, and the H. illucens larval meal complete replacement of fishmeal in the basal diet (HILM), for 28 days in ETEC-challenged pig housing. The results showed that the relative transcript abundances of ZO-1, pBD2, PR39, and PG1–5 were increased (p < 0.05) in pigs fed the HILM diet compared with those fed the NC diet. In addition, the HILM diet reduced (p < 0.05) the serum contents of IL-8 and increased (p < 0.05) the serum contents of IL-10 and IgG compared with the NC diet. In terms of the molecular mechanisms by which immune homeostasis is improved, the p-NF-κB/ NF-κB ratio and TLR2 protein expression in the colon were decreased (p < 0.05) in pigs fed the HILM diet compared with those fed the NC diet. Compared with the NC diet, the HILM diet reduced (p < 0.05) the protein expression of HDAC3 and HDAC7 in the colon of pigs. The SIRT1, acH3K9, and pH3S10 protein expressions in the colon were the greatest (p < 0.05) in pigs fed the HILM diet compared with the NC diet. HILM diets improved the colonic immune homeostasis in weaned piglets by enhancing the antimicrobial peptide expression, thereby mitigating ETEC challenges in pig housing. Mechanistically, HILM diets promote antimicrobial peptide expression through increased histone acetylation (acH3K9 and pH3S10). Full article

No vaccines are licensed against enterotoxigenic Escherichia coli (ETEC), a leading diarrheal cause in children and travelers. ETEC adhesins and enterotoxins are the virulence determinants and become the primary targets in ETEC vaccine development. However, ETEC strains produce > 25 adhesins and two potent enterotoxins, particularly the poorly immunogenic heat-stable toxin (STa), greatly hindering ETEC vaccine development. To overcome these challenges, we developed a multiepitope-fusion-antigen (MEFA) platform. MEFA presented multiple adhesin epitopes on a backbone and generated a polyvalent adhesin immunogen, CFA/I/II/IV MEF. CFA/I/II/IV protected against the seven ETEC adhesins (CFA/I, CS1-CS6) associated with two-thirds of ETEC diarrheal cases. We further used toxoids as safe antigens and created a toxoid fusion, 3xSTa_N12S-mnLT_R192G/L211A. This antigen induced antibodies neutralizing the enterotoxicity of STa and heat-labile toxin (LT), which, alone or together, cause all ETEC diarrheal cases. By combining two polyvalent proteins, we developed a multivalent ETEC vaccine, MecVax, that protects against seven ETEC adhesins and two enterotoxins. MecVax is broadly immunogenic. MecVax prevents intestinal colonization by ETEC strains expressing any of the seven adhesins and protects against clinical diarrhea from ETEC strains producing LT or STa enterotoxin preclinically, becoming a broadly protective ETEC vaccine candidate against children’s diarrhea and travelers’ diarrhea. 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

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in pigs. Virulence factors, such as colonization factors and enterotoxins, bind to specific receptors on intestinal epithelial cells (IECs), impairing the integrity of the IEC barrier by inducing cell death. Pyroptosis is a newly discovered form of programmed cell death (PCD), which is widely involved in the pathogenesis of multiple infectious gastrointestinal diseases. However, it is still unclear whether pyroptosis contributes to the ETEC-mediated damage of IECs. This study demonstrated that ETEC infection activated NLRP3 inflammasome and triggered gasdermin D (GSDMD)-executed pyroptosis of mouse IECs in vitro and in vivo. Mechanistically, ETEC infection triggered endoplasmic reticulum (ER) stress response to increase the expression of thioredoxin-interacting protein (TXNIP) by upregulation of C/EBP homologous protein (CHOP), which subsequently activated NLRP3 inflammasome. Removal of ER stress by tauroursodeoxycholic acid (TUDCA) alleviated the pyroptosis of IECs that was caused by ETEC infection. In addition, the induced ER stress impaired mitochondria and led to mitochondrial reactive oxygen species (mtROS) overproduction and cytosolic release of mitochondrial DNA (mtDNA), which activated STING, another factor that contributed to ETEC-triggered pyroptosis. Chemical inhibition of STING attenuated ETEC-induced pyroptosis of IECs. Collectively, this study demonstrated that the activation of the STING/ER stress/mitochondrial impairment/NLRP3 inflammasome axis is a critical pathway in the ETEC infection-derived pyroptosis of IECs. Hence, targeting ER stress response may serve as a promising therapeutic strategy to prevent ETEC infection caused damage to IECs. Full article

Post-weaning diarrhea caused by Enterotoxigenic Escherichia coli (ETEC) is a major disease in piglets and leads to substantial economic losses in the swine industry. Compared to conventional lysozyme, yak stomach lysozyme (YSL) demonstrates distinctive resistance to pepsin, trypsin, high temperature, and acidic conditions. This study investigated the effects of dietary YSL supplementation on intestinal health in weaned piglets challenged with ETEC, utilizing metabolomics and proteomics. A total of 18 weaned piglets were randomly divided into three groups: control (C), diarrhea (D), and YSL treatment (YLT). Groups C and D were fed a basal diet, while the YLT group received the basal diet supplemented with YSL at a dosage of 100,000 U/kg following ETEC challenge. Following an acclimation period, piglets in groups D and YLT were orally challenged with ETEC, while group C received the same volume of sterile LB broth. The feeding trial lasted for 21 days before sample collection. The results demonstrated that dietary supplementation with YSL significantly reduced the diarrhea rate (p < 0.05). Compared with the D group, the YLT group exhibited significantly increased serum albumin levels (p < 0.05), along with a tendency toward greater villus height (p = 0.085) and higher serum glucose levels (p = 0.052), indicating an improvement in nutritional and metabolic status Metabolomic analysis identified 260 differentially abundant metabolites between the YLT and D groups (81 upregulated, 179 downregulated), which were predominantly enriched in pathways related to amino acid biosynthesis and metabolism, purine metabolism, and nucleic acid metabolism. Proteomic profiling revealed 571 differentially expressed proteins (237 upregulated, 334 downregulated). Upregulated proteins were mainly involved in arginine biosynthesis and base excision repair, while downregulated proteins were associated with the PPAR signaling pathway and Salmonella infection. In summary, dietary YSL supplementation alters the metabolic and proteomic profiles in the intestines of diarrheic piglets, potentially improving gut barrier function and nutrient utilization. This study offers novel insights into the potential of YSL as a promising feed additive for prevention of post-weaning diarrhea in pigs. Full article

Background/Objectives: The incidence of early-onset colorectal cancer (EOCRC) is rising worldwide, although its biological and clinical features remain incompletely understood. Emerging evidence implicates gut microbial dysbiosis as a key driver of EOCRC pathogenesis, acting through complex interactions with host genetics, mucosal immunity, and early-life exposures. This review synthesizes current evidence on EOCRC-specific microbial signatures, delineates host–microbiome interactions, and evaluates how these insights may inform precision prevention, early detection, and therapeutic strategies. Methods: A systematic literature search was conducted in PubMed, Scopus, and Web of Science up to August 2025, using combinations of “early-onset colorectal cancer,” “gut microbiome,” “dysbiosis,” and “host–microbiome interactions.” Both clinical and preclinical studies were included. Extracted data encompassed microbial composition, mechanistic insights, host-related factors, and microbiome-targeted interventions. Evidence was synthesized narratively to highlight consistent patterns, methodological limitations, and translational implications. Results: EOCRC is consistently associated with enrichment of pro-inflammatory and genotoxic taxa (e.g., Fusobacterium nucleatum, colibactin-producing Escherichia coli, enterotoxigenic Bacteroides fragilis) and depletion of short-chain fatty acid–producing commensals. Multi-omics analyses reveal distinct host–microbiome signatures influenced by germline predisposition, mucosal immunity, sex, and early-life exposures. However, substantial methodological heterogeneity persists. Collectively, these data point to candidate microbial biomarkers for early detection and support the rationale for microbiome-targeted preventive and adjunctive therapeutic approaches. Conclusions: EOCRC harbors unique microbial and host–environmental features that distinguish it from late-onset disease. Integrating host determinants with microbiome signatures provides a framework for precision prevention and tailored therapeutic strategies. Future priorities include harmonizing methodologies, validating microbial biomarkers in asymptomatic young adults, and rigorously testing microbiome-targeted interventions in clinical trials. Full article

Foodborne pathogens represent a significant public health risk in both developed and developing countries. Among these pathogens, enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in humans and one of the leading causes of mortality in newly weaned pigs. The main sources of ETEC contamination include environments with poor hygiene and contaminated water, meat, cereals, and vegetables. Therefore, this review manuscript focuses on the pathogenesis of ETEC in humans and pigs. The main virulence factors responsible for ETEC-associated infections, such as colonization factors and toxins, will be described for both species, with particular emphasis on the toxins as well as, their classification and structural characterization. More specifically, this study will outline the main physiological alterations and adaptive mechanisms induced by these enterotoxins, namely heat-stable toxin (ST) and heat-labile toxin (LT), in the three most affected systems: the gastrointestinal system, the enteric nervous system (ENS), and the immune system. This set of findings provides a deeper insight into the pathogenesis of this relevant foodborne pathogen, which is crucial for empowering food scientists and stakeholders to more effectively mitigate associated risks. As such, it provides valuable understanding of toxin activity, serving as a means to raise awareness of food safety practices and strengthening risk communication, surveillance and intervention strategies, thereby ensuring consumer protection. Additionally, this knowledge enables the development of preventive strategies to reduce ETEC infections, thereby decreasing the need for clinical management among consumers exposed to this bacterium. Ultimately, it contributes to the preservation of public health, the reduction of antimicrobial use, and the lowering of antimicrobial resistance gene prevalence. 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

Background: Enterotoxigenic Escherichia coli (ETEC) is a zoonotic pathogen causing diarrhea and mortality in infants and livestock. Its numerous serotypes necessitate the urgent development of multivalent vaccines for effective prevention, thereby reducing public health and economic threats. Methods: Computational bioinformatics analyses were conducted on five major ETEC adhesins structural subunits (FaeG, FanC, FasA, FimF41a, and FedF). Dominant epitopes were selected and concatenated via flexible linkers, incorporating the PADRE sequence and LTb adjuvant to design a multi-epitope fusion antigen (MEFA). The recombinant MEFA protein was expressed in a prokaryotic system. Furthermore, molecular dynamics simulations, docking, and immune simulations assessed structural stability and immunogenicity. Immunoreactivity was tested by Western blot. Murine immunization evaluated antibody responses, lymphocyte proliferation, cytokine secretion, and protection against ETEC challenge. Results: Structural modeling showed an extended conformation, with docking and simulations indicating strong immune activation. Western blot confirmed MEFA immunoreactivity. MEFA induced high antigen-specific antibody titers, enhanced splenocyte proliferation, and increased IFN-γ and IL-4 secretion, indicating a Th2-biased response in mice. Vaccinated mice survived lethal ETEC challenge and maintained intestinal integrity. Conclusions: The MEFA candidate vaccine effectively induces robust humoral and cellular immune responses and provides protection against ETEC infection, representing a promising strategy for next-generation multivalent ETEC vaccines. Full article

Several different pathogens, including Escherichia coli, are strongly associated with calf diarrhoea. The population diversity of intestinal E. coli within each diarrhetic calf and between diarrhetic calves is not well understood. In the present study, 391 faecal samples were obtained during 2023–2024 from Danish dairy calves with diarrhoea. Semi-quantified growth estimates of E. coli after culturing did not reflect the diarrhetic grade nor whether E. coli was the only pathogen observed in the sample. From each sample, five isolates were subjected to multiple-locus variable-number tandem repeat analysis (MLVA) and revealed that 70% of faecal samples contained more than one type of E. coli. Genotyping, sequence typing and in silico serotyping showed a large diversity of E. coli between faecal samples. Surprisingly, isolates with a genotype representing mixed features of Diffusely adhering E. coli/Extraintestinal pathogenic E. coli were found in 25% of the isolates, while the classic Enterotoxigenic E. coli genotype was only observed in 5% of the isolates, and only 4% of the faecal samples were positive for E. coli F5 (K99) fimbriae, as determined by PCR. In conclusion, a diverse population of (non-F5) E. coli is associated with diarrhoea in calves. High genomic diversity of E. coli within samples needs to be considered when selecting only one isolate for antimicrobial resistance profiling and vaccination measurements. Full article

This study focused on utilizing the double-mutant heat-labile toxin (R192G/L211A) (dmLT) as a backbone protein, into which neutralizing epitopes of ETEC (FaeG, FedF, FanC, FasA, and Fim41a) were embedded. A combination of computational modeling and immunogenicity analysis was conducted to evaluate the dmLT_{(R192G/L211A)} multiepitope fusion antigen (MEFA). Both the computational modeling and experimental results confirmed that all relevant epitopes were clearly exposed on the surface of the MEFA. Subcutaneous immunizations of rabbits with the MEFA protein yielded the development of IgG antibodies that targeted all five fimbriae. Furthermore, these antibodies demonstrated significant inhibition of adhesion for K88+, K99+, 987P+, F18+, and F41+ ETEC strains to porcine small intestinal epithelial cell line IPEC-J2 cells. These results indicated that the dmLT toxoid-based MEFA protein effectively elicits high-titer, functional antibodies capable of neutralizing the attachment of multiple prevalent ETEC fimbrial types, highlighting its potential as a broad-spectrum vaccine candidate. Consequently, it shows promising potential as a broad and effective vaccine against ETEC. Full article

Colorectal cancer (CRC) remains a major global challenge, with growing attention to its pathogenesis as mediated by the gut microbiome and epigenetic regulation. Despite therapeutic progress, clinical management remains difficult. CRC accounts for ~10% of cancers and is the second leading cause of cancer death worldwide. Romania bears a substantial burden, with many diagnoses at advanced stages. Etiology—Integrated Genetic, Environmental, and Microbial Determinants. Hereditary syndromes explain 10–15% of cases; most are sporadic, with hypermutated MSI/POLE (~15%), non-hypermutated chromosomal instability (~85%), and a CpG island methylator phenotype (~20%). GWAS implicate loci near SMAD7, TCF7L2, and CDH1; in Romania, SMAD7 rs4939827 associates with risk. Lifestyle exposures—high red/processed meat, low fiber, adiposity, alcohol, and smoking—shape susceptibility. Microbiome–Epigenome Interactions. Dysbiosis promotes carcinogenesis via genotoxins (e.g., colibactin), hydrogen sulfide, activation of NF-κB/STAT3, barrier disruption, and epigenetic remodeling of DNA methylation and microRNAs. Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and pks⁺ Escherichia coli exemplifies these links. Population-Specific Risk—Romania within Lifestyle–Microbiome Evidence. Incidence is rising, including early-onset disease. Romania lacks CRC-specific microbiome datasets. However, metabolic cohorts show loss of butyrate producers, enrichment of pathobionts, and SCFA imbalance—patterns that mirror European CRC cohorts—and exhibit regional heterogeneity. Beyond Fusobacterium nucleatum. Additional oncobacteria shape tumor biology. Peptostreptococcus stomatis activates integrin α6/β4→ERBB2–MAPK and can bypass targeted inhibitors, while Parvimonas micra enhances WNT/β-catenin programs and Th17-skewed immunity. Together, these data support a systems view in which microbial cues and host epigenetic control jointly drive CRC initiation, progression, metastasis, and treatment response. Full article