title: Characterization of Diarrheagenic Antimicrobial Resistant Escherichia coli Isolated From Pediatric Patients in Tehran, Iran.
abstract: BACKGROUND
  Acute infectious diarrhea is one of the most important causes of morbidity and mortality worldwide.
  
  
  OBJECTIVE
  The objective of this study was to characterize antimicrobial resistant diarrheagenic Escherichia coli strains isolated from diarrheic children in Tehran, IR Iran.
  
  
  METHODS
  In total, 550 stool samples from diarrheic pediatric patients, aged less than 60 months, were collected and immediately transferred to the laboratory. Isolation and identification of E. coli strains was done using bacteriological methods. Antimicrobial susceptibility testing was performed using the disk diffusion technique. Multiplex PCR was used to detect aadA1, tetA, tetB, dfrA1, qnr, aac (3)-IV, sul1, blaSHV, CITM, cat1, and cmlA antibiotic resistance genes.
  
  
  RESULTS
  From the total of 550 fecal samples examined, 154 samples (28%) were positive for diarraheagenic E. coli. High rates of antibiotic resistance were seen against penicillin ﴾100%), ampicillin ﴾89.6%﴿ and tetracycline ﴾83.1%﴿. Resistance against ciprofloxacin was low ﴾28.6%﴿. The prevalence of different resistance genes in the studied strains varied from 96.10% for aadA1 gene to 40.25% for sul1 gene. The frequencies of aadA1, tetA, tetB, dfrA1, qnr, aac(3)-IV, sul1, blaSHV, CITM, cat1, and cmlA genes were 96.10%, 85.06%, 84.41%, 51.94%, 72.07%, 54.54%, 40.25%, 57.79%, 90.25%, 59.74% and 60.38%, respectively.
  
  
  CONCLUSIONS
  Our results indicated that antibiotic resistance is increasing in diarraheagenic E. coli strains in Iran. It is imperative to develop strategies for prevention and control of resistant organisms. Changes in patterns of resistance against commonly used antibiotics in Iran indicate that an applied surveillance system and introduction of guidelines for appropriate antibiotic prescription are necessary.
authors.affiliation: Department of Microbiology, Falavarjan Branch, Islamic Azad University, Falavarjan, IR Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Heidary
authors.affiliation: Department of Microbiology, Shahrekord Branch, Islamic Azad University, Shahrekord, IR Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Momtaz
authors.affiliation: Department of Microbiology, Falavarjan Branch, Islamic Azad University, Falavarjan, IR Iran.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Madani
keywords: Escherichia coli; Multiplex Polymerase Chain Reaction; child