Prevalence of childhood diarrhoea-associated Escherichia coli in Thailand

Escherichia coli isolates (n = 2629) were collected between 1996 and 2000 from 2100 Thai children less than 12 years of age with acute diarrhoea. Enterotoxigenic (ETEC), enteroinvasive (EIEC), Shiga-toxin-producing (STEC), enteropathogenic (EPEC) and enteroaggregative (EAEC) E coli were identified by their virulence marker profiles, as determined by multiplex PCR, and HeLa. cell-adherence patterns. Serogroups of isolates were determined using 43 monovalent 0 antisera. Of 2629 isolates, 16(.)9% were identified as diarrhoeagenic E coli, and the mean isolation rates per year were 10.2% for EAEC (range 8-12(.)5%), 3(.)2% for EPEC (0-8%), 3-0% for ETEC (2-5(.)4%), 0-5% for EIEC (0-1%) and 0-04% for STEC(0-0.1%). The isolation rates of pathotypes from four different age groups (0-5 months, 6-11 months, 1-2 years and 2-12years) in 905 children whose ages were recorded were respectively 19(.)3, 18(.)2, 9(.)1 and 8(.)1% for EAEC, 3(.)1, 4(.)3, 1(.)7 and 2(.)2% for EPEC and 2(.)6, 2(.)3, 1(.)3 and 5% for ETEC. About 38% of diarrhoeagenic E coli, including 55(.)1, 66(.)7, 100, 45(.)9 and 29%, respectively, of ETEC, EIEC, STEC, EPEC and EAEC, and 24% of non-diarrhoeagenic E. coli were O-antigen typable. Only four serogroups (9(.)3%) were restricted to single pathotypes, whereas 27 serogroups (62(.)8%)were not restricted to any pathotype. This study shows that EAEC are the most prevalent diarrhoea-associated pathotype in Thai children.