Phenotypic and Genotypic Characterization of Enteroaggregative Escherichia coli Strains Isolated From Diarrheic Children in Iran

Several studies performed in developed and developing countries have identified enteroaggregative Escherichia coli (EAEC) as the emerging cause of pediatric diarrhea. This study investigated the phenotypic and genetic characteristics of EAEC strains isolated from children with diarrhea between 2007 - 2008 in Tehran, Iran. EAEC strains were examined for virulence plasmid genes (aap, aggR, and aatA), biofilm formation, and drug resistance. In addition, pulsed-field gel electrophoresis (PFGE) profiles of these strains were determined. Significant percentage of local EAEC strains carried the virulence plasmid genes and formed biofilms. In addition, these strains showed high resistance to ampicillin (100%), tetracycline (65.7%), streptomycin (58.7%), chloramphenicol (52.6%), and trimethoprim/sulfamethoxazole (51.7%) and had different PFGE patterns. These results indicated that EAEC strains isolated from Iranian children with diarrhea were heterogeneous and showed high resistance rates against commonly used antibiotics, which was similar to that reported in studies performed in other countries.