VIRULENCE PLASMIDS OF ENTEROTOXIGENIC ESCHERICHIA-COLI ISOLATES FROM PIGLETS

Virulence plasmids of 68 ETEC isolates from piglets belonging to diffe rent pathotypes and six ETEC isolates from calves with pathotypes typi cal of porcine ETEC were identified with seven virulence probes for th e heat-stable (STa and STb) and heat-labile (LT) enterotoxins, for the F4, F5, F6, and F41 fimbrial adhesin subunit, and also with five Rep probes for the RepFIA and RepFIB basic replicons, and the RepFIC famil y of basic replicons, With the exception of the F41 probe, the other v irulence probes hybridized with at least one plasmid band of a size ra nge from 65 to more than 100 Mda. Common associations of virulence fac tor-encoding genes on plasmid bands were: STb/LT, STa/F5, STa/F6, STa/ STb, Other associations, STa/F4, STa/F4/F6, and STa/STb/LT/F6, were ra rer. On the other hand the F4 adhesin-encoding genes were isolated on one plasmid band in all but three F4+ isolates, All but one of the 92 virulence plasmids which were studied have Rep probe hybridization pro files and replicon types typical of the uni- or multireplicon plasmids belonging to the various incompatibility groups of the F incompatibil ity complex. (C) 1998 Elsevier Science B.V. All rights reserved.