Hemagglutination patterns of enterotoxigenic and enteropathogenic Escherichia coli determined with human, bovine, chicken, and guinea pig erythrocytes in the presence and absence of mannose.

A hemagglutination (HA)-typing system has been developed for the presumptive identification of enterotoxigenic Escherichia coli (ETEC) possessing the colonization factor antigens (CFA) CFA/I or CFA/II. E. coli isolates are grown on CFA agar and tested for mannose-sensitive (MS) or mannose-resistant (MR) HA of human, bovine, chicken, and guinea pig erythrocytes. CFA/I-positive ETEC exhibit MRHA with human, bovine, and chicken erythrocytes, but no HA with guinea pig erythrocytes. CFA/II-positive ETEC produce HA (MRHA) only with bovine and chicken erythrocytes. Common pili appear to be the primary MS-hemagglutinin of E. coli because the prototype strain K-12 exhibits HA (MSHA) with all but bovine erythrocytes. However, only 6.6% (23 of 351) of E. coli belonging to the classical enteropathogenic E. coli serogroups (EPEC) possessed the same HA pattern as strain K-12; 42% of the EPEC cultures (146 of 351) were similar to K-12 in producing MSHA with chicken and guinea pig erythrocytes and no HA with bovine erythrocytes, but different in that these produced either no HA or MRHA with human erythrocytes. These EPEC-associated HA patterns were assigned to a separate category, termed HA type III. Non-EPEC serogroups associated with sporadic diarrhea (i.e., the facultatively enteropathogenic E. coli, or FEEC) and 41% (19 of 46) of available Salmonella isolates also produced HA type III patterns. This observation is of considerable interest because many FEEC possess somatic antigens cross-reactive with Salmonella. Although the biochemical basis for this result has not been established, the data reported herein suggest a relationship between the HA type III phenotype and virulence (enteropathogenicity) in both the EPEC and FEEC serogroups. We propose that HA typing be used in conjunction with serotyping of E. coli to determine the degree of association of HA type III E. coli with sporadic diarrhea in infants and young children.