Organisation and in vitro expression of esp genes of the LEE (locus of enterocyte effacement) of bovine enteropathogenic and enterohemorrhagic Escherichia coli40

Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli infections are characterised by the formation of attaching and effacing (AE) lesions on intestinal epithelial cells. Secretion of extracellular proteins (EspA, EspB, and EspD) via a type III secretion apparatus is necessary for the formation of the AE lesions by human EPEC. In this study, we show that bovine EPEC and EHEC are also able to secrete polypeptides homologous to the already described Esp proteins, most probably via a type III secretion system. Bovine EPEC and EHEC strains present two different secretion profiles of Esp proteins which correlate to the pathotypes of the esp genes as determined by PCR. We also demonstrate that genes encoding secreted proteins, present in the LEE of two bovine strains, are organised in the same way as in the human EPEC strain E2348/69</p

Genotypic characterization of enteropathogenic Escherichia coli (EPEC) isolated in Belgium from dogs and cats41

Enteropathogenic Escherichia coli (EPEC) are isolated from man and farm animals but also from dogs and cats. They produce typical histological lesions called &#039;attaching and effacing&#039; lesions. Both plasmid and chromosomal elements are involved in the pathogenesis of EPEC infection. The presence of these genetic elements was investigated in 14 dog and three cat EPEC isolates. A bfpA-related gene was detected in five of the 17 isolates in association with high molecular weight plasmids, and a locus of enterocyte effacement (LEE) was present in all isolates. The LEE was inserted in the selC region in only 12% of the isolates. The eae, tir, espA and espB genes were analyzed by multiplex PCR. The results indicated the presence of those genes in the tested isolates with heterogeneity in the gene subtypes present: eae gamma-tir alpha-espA alpha-espB alpha (65%), eae beta-tir beta-espA beta-espB beta (29%), eae alpha-tir alpha-espA alpha-espB alpha (6%). Moreover, the espD gene was also present in dog and cat EPEC. The DEPEC and CEPEC form a heterogeneous group and five of them are closely related to human EPEC</p

Comparison of eae, tir, espA and espB genes of bovine and human attaching and effacing Escherichia coli by multiplex polymerase chain reaction44

Attaching and effacing Escherichia coli (AEEC) virulence genes include the eae, the tir, the espA and the espB genes. These genes have been sequenced from several AEEC strains. The sequences alignments revealed the presence of constant and variable regions. Multiplex polymerase chain reactions were developed, in order to determine the subtype of each gene present in a particular isolate. AEEC strains isolated from calves dead of diarrhea, from healthy calves and from infected humans were compared. The same pathotypes were found in sick and healthy calves but in inverted proportion. These pathotypes were also found in human AEEC. Although, the human EHEC strains from serotype O157 possessed their own pathotype</p

Bacterial Intestinal Flora Associated with Enterotoxaemia in Belgian Blue Calves

The enterotoxaemia syndrome in Belgian Blue calves is characterised by a high case fatality rate, sudden death, lesions of haemorrhagic enteritis of the small intestine and, quite often an absence of other clinical signs but its cause has not been yet identified. As a first step in this identification, the aerobic and anaerobic intestinal flora of a population of 78 calves, originating from farms located in southern Belgium and that died in circumstances defined as "calf enterotoxaemia" (study population) and of 64 calves that died in other circumstances (control population) were studied qualitatively and quantitatively. The colonies were identified after subcultures with appropriate API sugar sets. Anaerobically Clostridium perfringens was isolated in higher numbers (mean values of 10(7)-10(7.5) colony forming units (CFU) versus 10(4)-10(5) CFU per ml of intestinal content) and from more animals (79 versus 19%) in the study population than in the control population, although individual results from both populations could overlap. Other clostridial species, i.e. mainly urease-negative C. sordellii and C. bifermentans, were isolated in high numbers (>10(6) CFU per ml of intestinal content) from a few animals in the study population only. All but one of the 705 C. perfringens isolates from both populations belonged to the A toxin type and none of the urease-negative C. sordellii was toxigenic. Gram-negative anaerobes were not isolated in high numbers from any of the samples. Aerobically beta-haemolytic E. coli were significantly more frequent among the study population, but were isolated from only 25% of the animals. Salmonella Typhimurium was isolated from only two animals in the study population. Less than 1% of the E. coli isolated were verotoxigenic and one-third were necrotoxigenic. At this stage only non-enterotoxigenic type A C. perfringens are thus statistically associated with the enterotoxaemia syndrome in Belgian Blue calves and fulfil the first of the Koch's postulates

Heterogeneity of the eae genes in attaching/effacing Escherichia coli from cattle: comparison with human strains45

Enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli isolated from cattle were studied by DNA colony hybridization to subtype their intimin-encoding (eae) gene with probes derived from the variable parts of the eae alpha gene of the human EPEC strain E2348/69, the eae gamma gene of the human O157:H7 EHEC strain ATCC43888, and the eae beta gene of the bovine O26:H- EHEC strain 193, whose eae gene was first cloned and sequenced during this work. The EPEC and EHEC had been isolated from diarrhoeic calves (143 EPEC and 48 EHEC) and from healthy animals at the slaughterhouse (10 EPEC and 34 EHEC). The 191 bovine EPEC and EHEC isolated from diseased calves were positive with the Eae beta probe (55 and 27% respectively) and with the Eae gamma probe (9 and 73% respectively), whereas 52 EPEC (36%) were negative with the Eae alpha, Eae beta, and Eae gamma probes. The results were different for the 44 bovine EPEC and EHEC isolated from healthy cattle at slaughterhouses: most tested positive with the Eae gamma probe (80 and 82% respectively) and the remaining (20 and 18% respectively) with the Eae beta probe. Nine O26 human EHEC tested positive with the Eae beta probe and seven O111 with the Eae gamma probe. The bovine and human EPEC and EHEC belonging to these two serogroups gave identical results: the 18 bovine and human O26 isolates tested positive with the Eae beta probe, whereas the 13 O111 isolates were positive with the Eae gamma probe. In contrast, the isolates belonging to other serogroups (O5, O15, O18, O20, and O118) gave more variable results. The eae beta and eae gamma, but not the eae alpha, variants were thus distributed amongst bovine EPEC and EHEC. The eae beta variant seemed to be more frequently associated with the presence of clinical signs in calves, but one third of EPEC from diarrhoeic calves carried an eae gene variant other than the alpha, beta, or gamma variants. In addition, the use of these gene probes did not enable differentiation between bovine and human EHEC belonging to the same O serogroup</p

Pathotypes of bovine verotoxigenic Escherichia coli isolates producing attaching/effacing (AE) lesions in the ligated intestinal loop assay in rabbits51

Effacement of the microvilli and intimate attachment to the enterocytes (AE lesions) are two common properties of enteropathogenic (EPEC) and many verotoxigenic (VTEC) E. coli isolates from humans and animals. However not all of the several chromosomal and plasmidic genes and loci involved in the pathogenesis of the human EPEC strain E2348/69 are present in EPEC and VTEC isolates from animal species. We here report that in addition to verotoxin-encoding genes, bovine VTEC isolates harbour a variant of the original eaeA gene, confirming previous results, but neither the eaf nor the hfp loci which are involved in early attachment stage, and that not all of them possess an eaeB gene, as determined by the colony hybridization assay. Have these bovine VTEC isolates lost some of the loci or are they not necessary for the production of AE lesions in vivo? We also report the results of the ligated intestinal loop assay in rabbits with several bovine VTEC isolates. The production of AE lesions was correlated with the presence of an eaeA gene, but not with the presence of an eaeB gene, and was of course independent of the presence of the eaf and bfp loci. The eaeA-negative VTEC isolates produced no AE lesions. Either the eaeB gene is unnecessary for the production of AE lesions in the rabbit ligated intestinal loop assay or bovine VTEC possess other loci coding for similar functions. As to the adhesins involved in the early attachment step of bovine VTEC, they are most probably specific to cattle</p

Pathogenic Escherichia coli srains from dogs and cats: II clinical and bacteriological data on enteropathogenic E. Coli strains214

Clinical and bacteriological data on enteropathogenic Escherichia coli (EPEC) isolated from dogs and cats between 1979 and 1993 were collected as follows: (i) case history; (ii) in vivo production of attaching and effacing lesions; (iii) bio- and serotyping; (iv) antibiotic sensitivity. The clinical data for 13 dogs and three cats, showed an association with gastrointestinal pathologies (acute diarrhea/enteritis, sometimes haemorhagic, or subacute recurrent diarrhea/enteritis), sometimes lethal, in young animals (&lt; 3 months). The four strains studied in the rabbit ligated intestinal loop assay produced typical attaching and effacing lesions, although not consistantly. The biotypes of the 18 EPEC strains studied were classical of E. coli species, but for the production of an arginine dihydrolase (ADH), a test which was positive for 17 of them. On the other hand, none was haemolytic on sheep blood agar, nor was any serotypeable. Most of them were resistant to ampicillin and to the association amoxycilline/clavulanic acid</p