Hemagglutination activity and colonization factor antigens I and II in enterotoxigenic and non-enterotoxigenic strains of Escherichia coli isolated from humans

Abstract

There were 205 enterotoxigenic strains of E. coli examined for colonization factor antigens (CFA) I and II using an immunodiffusion technique with specific antisera. A total of 36 strains of serogroups O63, O78, O114, O128 and O153 and 1 rough strain possessed CFA/I and gave a single precipitin line; 47 strains of serogroups of O6, O8, 080, O85 and O115 possessed CFA/II. The latter strains gave a major precipitin line (component 3) when tested with specific antisera prepared against strain E1392 or PB-176 (both E. coli O6.H16; biotype A). All 16 strains of E. coli O6.H16 belonging to biotype A gave a 2nd precipitin line (component 1) when tested with both antisera. When CFA/II-positive strains were tested with a specific antiserum prepared against E. coli O6.H16 strains of biotype B or C, all strains gave component 3, but 16 of 17 strains of E. coli O6.H16 belonging to biotype B, C or F gave a 2nd precipitin line (component 2) not given by strains of biotype A. CFA/II-positive strains of serogroups other than O6 gave only component 3 in tests with all specific antisera. Nine enterotoxigenic strains of serotypes O7, O15, O25, O115 and O128 gave mannose-resistant hemagglutination of human or calf erythrocytes but lacked CFA/I or CFA/II. Although mannose-resistant hemagglutination was common in non-enterotoxigenic strains of E. coli none of the non-enterotoxigenic strains possessed CFA/I or CFA/II; these strains included fecal strains of serogroups O6, O8, O63 and O78, fecal strains of enteropathogenic serogroups and strains from extraintestinal sources.