A profile of drug resistance genes and integrons in E. coli causing surgical wound infections in the Faisalabad region of Pakistan

J Antibiot (Tokyo). 2009 Jun;62(6):319-23. doi: 10.1038/ja.2009.37. Epub 2009 May 15.

Abstract

Escherichia coli are one of the leading causes of infection in wounds. Emerging multiple drug resistance among E. coli poses a serious challenge to antimicrobial therapy for wounds. This study was conducted to ascertain a baseline profile of antimicrobial resistance in E. coli isolates infecting surgical wounds. A total of 64 pus samples from hospitalized patients were screened and 29 (45.3%) were found to have E. coli, which were identified biochemically and confirmed by molecular methods. Using the disc diffusion method, antimicrobial resistance was observed toward tetracycline (100%), cefradine (100%), nalidixic acid (93.1%), ampicillin (86.2%), gentamicin (86.2%), cefixime (82.8%), ceftriaxone (82.8%), aztreonam (82.8%), ciprofloxacin (75.9%), streptomycin (72.4%), cefoperazone (65.5%), chloramphenicol (58.6%) and amikacin (58.6%). In an effort to find relevant genes, 11 different genes were targeted by PCR. Among these, the mutated gyrA gene was found to be the most prevalent (82.8%), followed by the TEM (72.4%), catP (68.9%), catA1 (68.9%), tetB (62.1%), blt (58.6%), bla(CTX-M-15) (27.6%), bla(TEM) (20.7%), bla(OXA) (17.2%), tetA (17.2%) and aadA1 (13.8%) genes. The presence of integrons was also studied among these isolates. The prevalence of class 1 integrons was the highest (44.8%), followed by class 2 (27.6%). Three (10.3%) isolates carried both class 1 and class 2 integrons (first report from E. coli infecting wounds). The high incidence of integrons points toward their facilitation for carriage of antimicrobial resistance genes; however, in nearly 37% isolates, no integrons were detected, indicating the significance of alternative mechanisms of gene transfer. Another salient finding was that all isolates were multidrug-resistant E. coli.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • DNA, Bacterial / biosynthesis
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial / genetics*
  • Escherichia coli / drug effects*
  • Escherichia coli / genetics*
  • Escherichia coli Infections / microbiology*
  • Genes, Bacterial / genetics
  • Humans
  • Integrons / genetics*
  • Microbial Sensitivity Tests
  • Pakistan
  • Reverse Transcriptase Polymerase Chain Reaction
  • Surgical Wound Infection / microbiology*

Substances

  • Anti-Bacterial Agents
  • DNA, Bacterial