serotypes of enteropathogenic escherichia coli isolated from children under 5 years of age

background: the purpose of this study was to find out the frequency of different serotypes of enteropathogenic es­cherichia coli (epec) among healthy/diarrheal cases. methods: a total of 191 strains, 111 from diarrheal and 80 from asymptomatic persons were examined. determination of the epec sero­groups was performed by agglutination tests using polyvalent and monovalent o antiserum. pcr-rflp analysis of the flag­el­lin-encoding ( fli c) gene and agglutination tests using polyvalent and monovalent sera against   h antigens (h1 to h 56) according to the instructions of the manufacturer was performed.  results: seventeen (8.9%) strains were non-motile and untypable with conventional serotyping method that showed as h - . forty-three fli c restriction patterns were found for motile and non-motile serotypes. each motile sero-type was characterized by one or two flic specific restriction patterns. o142:h48 (6.8%), o86:h48 (6.3%), o111:h21 (4.7%) and o127:h21 (4.2%) were the most prevalent serotypes, and o55:h12/45, o86:h48, o127:h21, o142: h48, o126:h48 and o126:h19 sero­types were the most frequently agents in diarrheal cases, compared to asym-ptomatic children ( p < 0.05). there were com­mon epec serotypes in diarrheal and asymptomatic children, however some serotypes either found only in diarrheal cases or isolated from asymptomatic persons. conclusion: some serotypes were isolated more frequently from diarrheal cases than asymptomatic persons. the conven­tional serological method using antisera is the basis for the h typing system in e-coli , but it is impossible to serotype non-mo­tile bacteria. pcr-rflp analysis of fli c gene is a practical method in identifying the h variant in motile and non-motile epec serotypes and is useful for epidemiological studies.