Virulence factors of Escherichia coli. I. Mannose resistant haemagglutinating capacity is associated with serogroup but not with site of infection.

: Different serogroups of Escherichia coli strains originating from faeces (patients with enteritis 244, healthy individuals 225), urine (pyelonephritis 111, cystitis 130, asymptomatic bacteriuria 59) and other extraintestinal sources (blood 30, cerebrospinal fluid 15, wound 13, autopsy material 9, umbilicus 8, vagina 20, throat 13 and nose swabs 5) were examined for mannose resistant haemagglutination of human A erythrocytes (MRHA hum.). The most frequent serogroups were O1, O2, O4, O6, O7, O18 and O75 uniformly among faecal (26.5%), urinary (34%) and other extraintestinal (57.9%) strains. Haemagglutinating activity was significantly more frequent in these serogroups than in others (p less than 0.001). There was no significant association between MRHA positivity and origin of the serogroups. It has been concluded that MRHA hum. property of an E. coli strain depends on its serogroup rather than its origin. As these serogroups are the most frequent in the intestinal flora, it is assumed that their physiological function is to colonize the bowel and their pathological significance is to provide a source for extraintestinal infection.