Distribution of serogroups of 162 diarrheagenic E.coli strains isolated from children under five in Ha Noi

ABSTRACT

E. coli is an emerging diarrheagenic pathogen. Serotyping is important to identify bacteria and trace their epidemiology. Objectives: (1) To identify the distribution of serogroup O among 4 kinds of diarrheagenic E. coli strains isolated from children with and without diarrhea in Hanoi, Vietnam. (2)To find out the relationship between serogroup O and different diarrheagenic E. coli. Method: One hundred and sixty-two strains of diarrheagenic E. coli including 86 EAEC, 50 EPEC, 12 EIEC, and 14 ETEC have been serotyped by slide agglutination with antisera specific for O serogroups. Results: More than 60% of the strains were serotyped. Serogroup O25 was the most common with the prevalence of 16.7% followed by O15 (4.3%). The other serogroups (O127a, O128, O126, O6, and O16) were seen in very few numbers. 38.3% of E. coli strains were not serotypeable with available antisera. EAEC were the most prevalent among diarrheagenic E. coli and 25.6% of them belong to the serogroup O25. Conclusion: 60% of the diarrheagenic E. coli strains were serotyped. Serogroup 025 was the most common. The findings were very useful for assessing the distribution of serogroups of diarrheagenic E. coli and will be useful for future vaccine development.