A study of relationships among F17 a producing enterotoxigenic and non-enterotoxigenic Escherichia coli strains isolated from diarrheic calves

We investigated the clonal relationships among 41 enterotoxigenic (ETEC) or nonenterotoxigenic (NETEC) Escherichia coli strains producing the F17 a fi mbriae isolated from diarrheic calves in France or Belgium in the early 198 0s. Twenty-three of the 26 ETEC strains were highly clonally related, most of them with a O101:K32:H9-serotype. The NETEC strains were also divided in clonal subgroups, most of them with O101:H-serotype. The F17 a positive ET EC strains are no longer isolated from diarrheic calves in these countries. It is postulated that the use of a vaccine including O101, K32 and H9 anti gens in addition to K99 (F5) explains the strongly reduced isolation of the O101:K32:H9, K99 (F5) E. coli clone. (C) 1998 Elsevier Science B.V. All ri ghts reserved.