Summary.The prevalence of different types of diarrhoea-producing Escherichia coli was measured in 273 patients attending 12 out-patient clinics in Bandar-Abbas, State of Hormozgan, Iran, during March 1984. Enteropathogenic E. coli (EPEC) belonging to 12 different serogroups, of which 0128 and 0126 were the most common, were found in almost 31% of the patients. Enterotoxigenic strains of E. coli (ETEC) were the next most frequent group (21.9%); among these, 36 (60%) strains produced heatstable enterotoxin (ST), 14 (23.3%) strains produced both heat-labile enterotoxin (LT) and ST, and 10 (16.7%) strains produced LT only. The same pattern of toxigenicity was observed among the EPEC isolates. Ten of the 12 serogroups encountered in this study contained toxin producers, amongst which strains producing ST were dominant. Enteroinvasive E. coli (EIEC) strains were not isolated. These findings suggest that enterotoxin-producing E. coli may be an important cause of diarrhoea in this part of Iran.

A total of 70 enteropathogenic Escherichia coli (EPEC) strains belonging to 11 serogroups, isolated from infantile diarrhoea in Tehran, Iran, were tested for the production of verocytotoxin (VT), enterotoxin, and also for their adherence to HeLa cells. In total 55 (78.5%) strains were either VT (32 strains) or enterotoxin (23 strains) producers, and of these 8 strains produced both VT and enterotoxins. 57 (81.4%) strains showed either Localized (LA) or Diffuse adherence (DA) or both types of adhesion (LA/DA) on HeLa cells, with strains showing LA/DA in the same preparations being dominant (32 strains), followed by those showing LA (14 strains) and DA (11 strains). Among adherent EPEC, 26 (37.1%) strains belonging to the serogroups 020, 086, 0119, 0125, 0126, 0127 and 0128 also produced VT. These findings suggest that production of VT and enterotoxin is an important factor in the pathogenesis of EPEC diarrhoea in Iran and that the combination of adherence and production of toxins is a common feature of EPEC strains which cause diarrhoea in this country.