title: Distribution of class 1 integrons among enteropathogenic  Escherichia coli.
abstract: The aim of this study was to investigate the incidence of and resistance gene content of class 1 integrons among enteropathogenic Escherichia coli (EPEC) and non-EPEC and to investigate intraspecies genetic diversity of EPEC strains isolated from children with diarrhea in Iran. Twenty-eight EPEC and 16 non-EPEC strains isolated from children with diarrhea were tested for the presence of a class 1 integron associated integrase gene (int1). Sequence analysis was performed to identify the resistance gene content of integrons. Genetic diversity and cluster analysis of EPEC isolates were also investigated using enterobacterial repetitive intergenic concensus-polymerase chain reaction (ERIC-PCR) fingerprinting. Twenty-three (82%) EPEC isolates and 11 (68.7%) non-EPEC isolates harbored the int1 gene specific to the conserved integrase region of class 1 integrons. Sequence analysis revealed the dominance of dfrA and aadA gene cassettes among the isolates of both groups. ERIC-PCR fingerprinting of EPEC isolates revealed a high diversity among these isolates. The widespread distribution of 2 resistance gene families (dfrA and aadA) among both groups of EPEC and non-EPEC isolates indicates the significance of integrons in antibiotic resistance transfer among these bacteria. Furthermore, clonal diversity of EPEC isolates harbouring a class 1 integron also suggests the circulation of these mobile elements among a diverse population of EPEC in this country.
authors.affiliation: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Avenue, Tehran 14117-13116, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Najibi
authors.forename: B
authors.initials: B
authors.lastname: Bakhshi
authors.forename: S
authors.initials: S
authors.lastname: Fallahzad
authors.forename: M R
authors.initials: MR
authors.lastname: Pourshafie
authors.forename: M
authors.initials: M
authors.lastname: Katouli
authors.forename: M
authors.initials: M
authors.lastname: Sattari
authors.forename: M
authors.initials: M
authors.lastname: Alebouyeh
authors.forename: M
authors.initials: M
authors.lastname: Tajbakhsh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D017124:Conserved Sequence; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D054308:Enteropathogenic Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D019426:Integrases / Q000235:genetics; D032023:Integrons / Q000235:genetics*; D007492:Iran; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D019426:Integrases