Characterization of Shiga toxin producing E. coli and O157 serotype E. coli isolated in France from healthy domestic cattle

• Published in: International journal of food microbiology Vol. 63; no. 3; pp. 217 - 223
• Main Authors: Rogerie, François, Marecat, Armelle, Gambade, Stéphanie, Dupond, Francis, Beaubois, Pierre, Lange, Marc
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-02-2001; Elsevier
• Subjects: Abattoirs; Animal productions; Animals; asymptomatic infections; Bacterial Toxins; Bacterial Typing Techniques; Biological and medical sciences; bulls; Cattle; cattle manure; cows; dairy cows; eae gene; ehx gene; Epidemiology; Escherichia coli; Escherichia coli - classification; Escherichia coli - isolation & purification; Escherichia coli - pathogenicity; Escherichia coli O157 - classification; Escherichia coli O157 - isolation & purification; Escherichia coli O157 - pathogenicity; Feces - microbiology; Female; Food industries; Food microbiology; Food toxicology; France; Fundamental and applied biological sciences. Psychology; genes; Genes, Bacterial; genetic variation; Healthy cattle; Human physiology applied to population studies and life conditions. Human ecophysiology; Immunomagnetic Separation; Male; Meat - microbiology; meat carcasses; Medical sciences; nucleic acid hybridization; Nutritional survey. Food supply and nutritional requirement; Phenotype; Polymerase Chain Reaction; Serotyping; Shiga Toxin - biosynthesis; Shiga toxin producing E. coli; slaughterhouses; stx gene; surveys; Terrestrial animal productions; Vertebrates; Virulence - genetics; France; Europe; Western Europe; Shiga toxin producing E. coli; France; Epidemiology; Healthy cattle; Farming animal; Bovine; Escherichia coli; Polymerase chain reaction; Toxin; Vertebrata; Meat animals; Mammalia; Pathogenic; Bacteria; Poison; Artiodactyla; Field inquiry; Ungulata; Serotyping; Enterobacteriaceae
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/S0168-1605(00)00422-0

A study was carried out in France in collaboration with the meat industry to investigate the occurrence and characteristics of Shiga toxin-producing
E. coli (STEC) and O157
E. coli in a population of healthy bovines representative of French livestock. A total of 851 animals belonging to three bovine classes (106 young bulls, 374 dairy cows and 371 meat cows) were included in the study. Samples of feces and of the corresponding carcasses were collected from March 97 to August 97 in seven abattoirs spread throughout the national territory. STEC cultures from the 1702 samples were screened using PCR for the presence of
stx genes. Positive samples were further subjected to colony blot hybridization and to O157-specific immunomagnetic separation. Probe-positive colonies and O157 colonies were then analyzed for the presence of virulence genes and phenotypic characters (serotype, Stx production). In 154 (18.1%) feces and 91 (10.7%) carcass samples
stx genes were detected. Two hundred and twenty-two STEC colonies were isolated from 67 (7.9%) feces and 16 (1.9%) carcass samples, with 183 STEC isolated from feces and 39 from carcasses. Only eight O157 isolates were collected from feces samples. None of these O157
E. coli isolates presented
stx genes and thus could not be considered as pathogenic regarding hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). In 3.2% of STEC isolated from feces and in 10.2% of STEC from carcasses
eae genes were detected. In 17% of STEC from feces and in 30.7% from carcasses
ehx genes were detected. Using these data, the 222 STEC colonies could be classified in 11 different ‘virulence patterns’ (presence/absence of
stx1,
stx2,
eae and
ehx genes), showing that more than 77% of isolates presented only one virulence factor. Only three STEC on 222 colonies (1.3%) presented the three virulence factors
stx,
eae and
ehx in association, none of them reacting with antisera specific for enterohemorrhagic
E. coli. (EHEC). These data, together with the fact that only five isolates on the 222 (2.2%) reacted with such antisera (three O111 and two O26 isolates) demonstrated that the natural bacterial populations isolated during this study were clearly distinct from EHEC.