Prevalence and characteristics of necrotoxigenic Escherichia coli CNF1+ and CNF2+ in healthy cattle.
From February to July of 1994, 328 faecal samples from 32 herds were collected and examined for necrotoxigenic Escherichia coli (NTEC). Strains producing the cytotoxic necrotizing factors type 1 (CNF1) and type 2 (CNF2) were found on 4 and 63% of the farms, respectively. The proportion of animals infected within each herd varied from 0 to 38%. NTEC producing CNF2 were significantly more frequently isolated from calves (24%; 17 of 71) than from cows (4%; 11 of 257) (chi 2corr. 25.088; P < 0.001). Although the bovine CNF2+ strains belonged to 16 different serogroups, 5 (O15, O77, O88, O142 and O153) accounted for 44% of strains. This study confirmed that healthy cattle are a reservoir of NTEC producing CNF2, and revealed that CNF2+ strains are more frequently carried by calves than by adult cows.
Department of Microbiology and Parasitology, School of Veterinary Science, University of Santiago de Compostela, Lugo, Spain.
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D000383:Agriculture; D000818:Animals; D001427:Bacterial Toxins / Q000302:isolation & purification*; D002353:Carrier State; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D003603:Cytotoxins / Q000302:isolation & purification*; D004197:Disease Reservoirs; D004926:Escherichia coli / Q000145:classification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000662:veterinary*; D029968:Escherichia coli Proteins; D019081:O Antigens; D015995:Prevalence; D012703:Serotyping; D013030:Spain / Q000453:epidemiology
D001427:Bacterial Toxins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; D019081:O Antigens; C086995:cytotoxic necrotizing factor type 2; C060296:cytotoxic necrotizing factor type 1