Detection and Molecular Characterization of Enteroaggregative Escherichia Coli from Diarrheal Patients in Tertiary Hospitals, Southern Thailand.

Enteroaggregative Escherichia coli (EAEC) is a member of diarrheagenic E. coli, which plays an important role in human infections in developing countries. Investigations of EAEC in diarrheal patients at Hat-Yai and Pattani Hospitals, southern Thailand identified 5 EAEC strains, which were classified into serogroups, O44 and O127a. All 5 EAEC contained the global transcriptional regulator gene, aggR, and possessed fimbrial subunit genes, aggA and aafA, and EAEC-related toxin genes, astA and pet. PCR-based phylogenetic group assay revealed that the EAEC belonged to groups B1 and D. Low levels of clump formation were observed for all EAEC strains. Scanning electron microscopy showed an absence of fimbrial structure. DNA profiles generated by BOX- and ERIC2-PCR exhibited correspondingly identical patterns among all 5 EAEC strains, suggesting that they evolved from the same bacterial clone. Thus, there exists a low but still significant prevalence of EAEC-related diarrheal illnesses in the southern region of Thailand.