COLONIZATION FACTORS OF ENTEROTOXIGENIC ESCHERICHIA-COLI ISOLATED FROM CHILDREN IN NORTH-INDIA

Colonization factor antigens (CFAs) mediate attachment of enterotoxige nic Escherichia coli (ETEC) to the intestinal mucosa and induce protec tive immunity against ETEC diarrhea. ETEC strains (n = 111) isolated f rom North Indian children from 1985 to 1989 were examined for CFAs and putative colonization factors (PCFs). CFA/IV was the most common fact or (26%), followed by coli surface antigen 17 (CS17) (19%), CFA/I (14% ), PCFO166 (7%), and CFA/II (5%), while 24% of the isolates were negat ive for CFAs and PCFs. Among the strains producing heat-stable and hea t-labile toxin (ST(+)LT(+) strains), the STaI gene was strongly associ ated with the absence of known CFAs and PCFs, making the STaI(+)LT(+) isolates an interesting target for the identification of previously un described factors. Repetitive sequence-based polymerase chain reaction revealed that the CS17(+) strains, although clonally related, represe nted endemically circulating strains with a diversity greater than tha t of the CFA/I+ strains, which showed a substantial clonal clustering.