Prevalence of four enterotoxin (STaP, STaH, STb, and LT) and four adhesin subunit (K99, K88, 987P, and F41) genes among Escherichia coli isolates from cattle

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Abstract
Colony hybridizations with DNA probes for 3 heat-stable (STap, STaH, and STb) enterotoxins and 1 heat-labile (LT) enterotoxin and for 4 adhesins (K99, F41, K88, 987P) were performed on 870 Escherichia coli isolates to determine pathotypes prevalent among enterotoxigenic E coli (ETEC) isolated form cattle in Belginum. One hundred thirty-two E coli isolates (15.2%) hybridized with probes STap, K99, and/or F41. The 5 other probes were not hybridized by E coli isolates. Therefore, only STaP enterotoxin and K99 and F41 adhesins were virulence factors of ETEC isolated from cattle. Two major pathotypes accounted for 95% of the ETEC: STaP+ K99+ F41+ (67.4%) and STaP+ K99+ (27.3%). The last 5% of probe-positive isolates had STaP+ STaP+ F41+, or K99+ F41+ minor pathotypes. Of 12 American ETEC isolates also assayed, 7 were positive with STb and/or 987P probes (pathotypes STap+ STb+ STaP+ 987P+, or STaP+STb+987P+) and may be porcine-rather than bovine-specific enteropathogens. The remaining 5 American ETEC isolates belonged to 3 minor pathotypes (STaP+, STaP+, F41+, and K99+ F41+) also found among Belgian E coli isolates. Such isolates may be derivatives of STaP+ K99+ F41+ or STaP+ K99+ etec after in vivo or in vitro loss of virulence genes and /or non-etec isolates, which have acquired virulence genes by in vivo transfer. Colony hybridizations with DNA probes for 3 heat-stable (STap, STaH, and STb) enterotoxins and 1 heat-labile (LT) enterotoxin and for 4 adhesins (K99, F41, K88, 987P) were performed on 870 Escherichia coli isolates to determine pathotypes prevalent among enterotoxigenic E coli (ETEC) isolated form cattle in Belginum. One hundred thirty-two E coli isolates (15.2%) hybridized with probes STap, K99, and/or F41. The 5 other probes were not hybridized by E coli isolates. Therefore, only STaP enterotoxin and K99 and F41 adhesins were virulence factors of ETEC isolated from cattle. Two major pathotypes accounted for 95% of the ETEC: STaP+ K99+ F41+ (67.4%) and STaP+ K99+ (27.3%). The last 5% of probe-positive isolates had STaP+ STaP+ F41+, or K99+ F41+ minor pathotypes. Of 12 American ETEC isolates also assayed, 7 were positive with STb and/or 987P probes (pathotypes STap+ STb+ STaP+ 987P+, or STaP+STb+987P+) and may be porcine-rather than bovine-specific enteropathogens. The remaining 5 American ETEC isolates belonged to 3 minor pathotypes (STaP+, STaP+, F41+, and K99+ F41+) also found among Belgian E coli isolates. Such isolates may be derivatives of STaP+ K99+ F41+ or STaP+ K99+ etec after in vivo or in vitro loss of virulence genes and /or non-etec isolates, which have acquired virulence genes by in vivo transfer.

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