COLONIZATION ANTIGENS OF ENTEROTOXIGENIC ESCHERICHIA-COLI STRAINS ISOLATED FROM PIGLETS IN SPAIN

Eighty-eight enterotoxigenic E.coli strains isolated from 69 pigs with enteric infections (diarrhoea or oedema disease) were investigated fo r the presence of F4 (K88), F5 (K99), F6 (987P) and F41 colonization a ntigens. The commonest colonization antigen was F6 (987P), which was d etected in ETEC strains from 31.9% pigs, followed by F5 (K99) 11.6%, F 4 (K88) 10.1% and F41 8.7%. Presence of F6 (987P) and F5 (K99) fimbria e was statistically associated (0.025 > p < 0.005) with diarrhoeic pig lets younger than 15 days. F4 (K88) colonization antigen was only expr essed by ETEC isolated from piglets older than 15 days. 90.5% of ETEC isolated from 90.0% of piglets younger than 15 days expressed F5 (K99) , F6 (987P) or F41 antigens, whereas only 31.3% ETEC isolated from pig lets older than 15 days were positive for F4 (K88), F5 (K99), F6 (987P ) or F41 antigens (p < 0.001). None of the ETEC from pigs with oedema disease produced any of the four colonization antigens. ETEC bearing c olonization antigens were associated with particular serogroups and to xic phenotypes, whereas 4P(-) ETEC strains showed diverse phenotypic c haracteristics.