title: Genetic elements associated with antimicrobial resistance among intestinal bacteria.
abstract: BACKGROUND
  Integrons are the major reasons of multidrug resistance (MDR) among enteropathogenic bacteria. Occurrence of horizontal gene transfer between integron-carrying microorganisms and other enteric bacteria may increase the rate of emergence of integron-associated antibiotic resistance.
  
  
  OBJECTIVE
  The objective of this study was to investigate class 1 integrons among members of enteropathogenic bacteria isolated from patients in Iran.
  
  
  METHODS
  A total of 120 enteropathogenic bacterial isolates from diarrhoeal patients were included in this study. Identities of the isolates were investigated by biochemical tests and confirmed by genus or species specific PCRs. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Presence of class 1 integron among the isolates was investigated using primers specific for the integrase gene conserved region.
  
  
  RESULTS
  The result of this study showed the highest resistance to trimethoprim and cotrimoxazole, especially in enteropathogenic Escherichia coli (EPEC) (100%), Shigella sonnei (93.7%) and Vibrio cholerae (95%). The results showed that 16 (57.1%) of the 28 EPEC, 9 (25%) of the 36 Salmonella enterica, 32 of the 13 (40.6%) Sh. sonnei, and only 1 (4.2%) of the 24 V. cholerae isolate harbored class 1 integron.
  
  
  CONCLUSIONS
  The data obtained in the present study suggested that class 1 integrons are widely distributed among members of Enterobacteriaceae. The resistance patterns of our E. coli, S. sonnei, and S. enterica isolates were nearly identical, suggesting the same genetic elements involved in attainment of multi-drug resistance.
authors.affiliation: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran.
authors.forename: Bita
authors.initials: B
authors.lastname: Bakhshi
authors.affiliation: Department of Biology, Faculty of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, IR Iran.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Eftekhari
authors.affiliation: Department of Bacteriology, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Pourshafie
keywords: Antimicrobial Agents; Drug Resistance; Integrons; Intestinal Bacteria