Distribution of class 1 integrons among enteropathogenicEscherichia 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.

Clonal dissemination of a single Shigella sonnei strain among Iranian children during Fall 2012 in Tehran, I.R. Iran

“…Similar array of gene cassettes of class I integrons was primarily detected among enteric bacteria including Proteus, E. coli and Shigella spp. (Eftekhari et al, 2013;Hussein et al, 2009;Najibi et al, 2012). Moreover, comparable array of gene cassettes have been detected in Klebsiella pneumonia and UPEC (Lee et al, 2001).This may reveal the fact that the Enterobacteriaceae act as a reservoir of resistance genes that can be transferred to other species within or outside the family and alter the genetic contents and resistance potential in bacteria (Young and Amyes, 1986).…”

Molecular Characterization of Enterohemorrhagic <i>Escherichia coli</i> Isolates from Cattle

“…Four classes of integrons have been reported up to now, and the class I integrons are more commonly recognized among clinical isolates [ 21 , 30 ]. Several studies have shown the widespread distribution of integrons among enteric bacteria from different countries including Iran [ 12 , 16 , 19 , 25 , 26 , 28 ].…”

Genetic Elements Associated With Antimicrobial Resistance Among Intestinal Bacteria

“…sonnei , and S. enterica isolates were nearly identical, suggesting that probably these different species have similar mechanisms for attainment of MDR. All of these results together with earlier finding of the extremely efficient interspecies transfer of integron-carrying elements, illustrated that horizontal transfer of integron-carrying elements plays a dominant role in the development of MDR among members of Enterobacteriaceae , independent of species or origin of isolation (10). …”