OCCURRENCE, DISTRIBUTION, AND ASSOCIATIONS OF O-SEROGROUP AND H-SEROGROUP, COLONIZATION FACTOR ANTIGENS, AND TOXINS OF ENTEROTOXIGENIC ESCHERICHIA-COLI

Enterotoxigenic Escherichia coli (ETEC) is a leading cause of infectio us diarrhea worldwide. Four categories of antigens have been commonly studied: O serogroup, H serogroup, colonization factor antigens (CFA), and toxins. A database has been compiled from published reports of ne arly 1,000 ETEC isolates from 18 locations and analyzed to determine t he occurrence, distribution, and associations of O serogroup, H serogr oup, CFA, and toxin type. Tables listing the associations of antigens are presented. This analysis documents the widespread nature and varie ty of ETEC. Even the most common combination of antigens, O6:H16 CFA/I I LTST, accounted for only 11% of the ETEC isolates in the database. I t was isolated from 12 locations. Many phenotypes occurred only once. CFA detection based on enzyme-linked antibodies with polyclonal sera i s suggested as the preferred assay. A combination of CFA and toxin-bas ed antigens is suggested as the most practical vaccine.