Studies on enterotoxigenic Escherichia coli isolated from persons without diarrhoea in Western Australia

The epidemiology of enterotoxigenic Escherichia coli (ETEC) was studied in children without diarrhoea in two remote Aboriginal communities in tropical north-western Australia. Serial surveys of the same individuals during different seasons showed that isolations were much more frequent in the wet monsoonal summer than in the dry winter. All E. coli were isolated from symptomless children aged 5 years or less; in addition, clearance of ETEC carriage without treatment was observed in all individuals within 3 months of isolation. Of the 58 ETEC strains isolated, 40 had either an H32 or an O126 antigen. Five O antigens which have never been associated with ETEC (O2, O41, O71, O77 and O157) were found. A recently proposed system to detect ETEC, using groups of polyvalent antisera, would have detected only 3 out of these 58 ETEC strains.