Molecular analysis of enteropathogenic Escherichia coli (EPEC) isolates from healthy food-producing animals and humans with diarrhoea.

Enteropathogenic Escherichia coli (EPEC) is a pathogen associated with acute diarrhoea in humans. To determine whether EPEC isolated from healthy food-producing animals possesses the same virulence gene repertoire as EPEC isolated from human with diarrhoea, we compared six typical EPEC (tEPEC) and 20 atypical EPEC (aEPEC) from humans with diarrhoea and 42 aEPEC from healthy animals (swine, sheep and buffaloes), using pulsed-field gel electrophoresis (PFGE), virulence markers, serotyping and subtyping of eae and tir genes. We found that human and animal isolates shared virulence genes, including nleB, nleE and nleF, which were associated with human diarrhoea. Serogroups and serotypes identified in isolates of food-producing animals such as O26:H11, O128:H2, O76:H7, O103, O108, O111 and O145, have previously been implicated in human disease. The subtypes eae and tir were also shared between human and animal isolates, being eae-γ1 and eae-ß1 the most prevalent in both groups, while the most common tir subtypes were α and ß. Despite PFGE analysis demonstrating that EPEC strains are heterogeneous and there was no prevalent clone identified, EPEC isolated from humans and food-producing animals shared some characteristics, such as virulence genes associated with human diarrhoea, indicating that food-producing animals could play a role as reservoirs for those genes.

Shigatoxigenic and atypical enteropathogenic Escherichia coli in fish for human consumption

ABSTRACT Shigatoxigenic and enteropathogenic Escherichia coli with virulence and multidrug resistance profile were isolated from Nile tilapia. This study finding is of great importance to public health because they help understand this pathogen epidemiology in fish and demonstrate how these animals can transmit E. coli related diseases to humans.

Shigatoxigenic and atypical enteropathogenic Escherichia coli in fish for human consumption.

Shigatoxigenic and enteropathogenic Escherichia coli with virulence and multidrug resistance profile were isolated from Nile tilapia. This study finding is of great importance to public health because they help understand this pathogen epidemiology in fish and demonstrate how these animals can transmit E. coli related diseases to humans.

Detection of Shiga toxigenic (STEC) and enteropathogenic (EPEC) Escherichia coli in dairy buffalo.

Enteropathogenic (EPEC) and Shiga toxigenic (STEC) Escherichia coli are among the bacteria most associated with enteric diseases in man. The aims of this study were to determine the prevalence of STEC and EPEC in dairy buffalo and then characterize these isolates genetically. To determine the prevalence of these bacteria, samples were collected from the feces and milk of buffaloes. In total, 256 samples were collected in 3 samplings, of which 76 samples tested positive for either the stx1, stx2 or eae genes or a combination thereof. From the positive samples, 22 STEC and 11 atypical EPEC (aEPEC) isolates were obtained. The isolates showed 23 different genetic profiles. No profile was very frequent in STEC isolates. On the other hand, the profile eae+, ehxA+, iha+, efa1+, toxB+, paa+, lpfAO113+ was found in 45% of the aEPEC isolates. In addition to stx1, stx2 and eae, the genes ehxA, efa1, saa, lpfAO113, lpfAO157/OI-141, lpfAO157/OI-154, toxB and iha were present in the isolates. Serogroup O26 was found in 26% of the aEPEC. Other serogroups detected include O87, O145, O176 and O179. The isolates were sensitive to almost all drugs tested and some isolates shared the same fingerprint patterns by enterobacterial repetitive intergenic consensus sequence-PCR (ERIC-PCR). The results suggest that, besides major reservoirs of STEC, buffaloes are also aEPEC reservoirs. The detection of a serogroup (O26), and putative virulence genes (efa1 ehxA, paa and lpfAO113), previously associated with aEPEC isolated from humans with diarrhea in aEPEC from buffaloes should be studied further.

Shiga toxigenic and atypical enteropathogenic Escherichia coli in the feces and carcasses of slaughtered pigs.

Escherichia coli is a pathogen of major importance in swine and public health. To determine the prevalence of Shiga toxigenic E. coli (STEC) and enteropathogenic E. coli (EPEC), samples were collected from the feces and carcasses of swines. In total, 441 samples were collected in four samplings, of which 141 samples tested positive for either the stx1, stx2, and/or eae genes. From the positive samples, one STEC and 15 atypical EPEC (aEPEC) isolates were obtained, and all originated from the same sampling. In addition to eae, lpfA(O157/OI-141), ehxA, toxB, and lpfA(O113) were present in the aEPEC isolates. The only stx2-containing isolate carried stx2e and belonged to serotype O103:HNT. Resistance to four or more antimicrobials was found in almost half of the isolates, and some isolates shared the same fingerprint patterns by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The presence of certain virulence genes and the high level of resistance to antimicrobials, as well as the possible fecal contamination of carcasses showed that some of the isolates are of public health concern.