Emergence of carbapenem-resistant Acinetobacter baumannii in hospitals in Pakistan

J Med Microbiol. 2014 Jan;63(Pt 1):50-55. doi: 10.1099/jmm.0.063925-0. Epub 2013 Oct 1.

Abstract

The emergence of pan-resistance in bacterial pathogens poses a threat to human health. Carbapenem-resistant Acinetobacter baumannii has emerged as a serious challenge, causing nosocomial infection and community-acquired outbreaks in hospitals globally, including in Pakistan. We collected 90 Acinetobacter isolates from patients with secondary or nosocomial infections from different hospitals in Pakistan and screened for carbapenem-resistant strains. Of the 90 isolates, 59 were resistant to carbapenems. Among oxacillinase -encoding genes, blaOXA-51-like was common in all isolates, including in combination with blaOXA-23-like in 14 isolates; however, blaOXA-24-like and blaOXA-58-like were completely absent. Among metallo-β-lactamase-encoding genes, only blaNDM-1 was found in one isolate, while the other three genes, blaIMP, blaVIM and blaSIM, were completely absent. None of the isolates was found to harbour the blaCTX-M gene. The isolates were also tested for susceptibilities to a panel of different antibiotics belonging to several classes. Of all the drugs tested, tigecycline was the most effective with 80 % sensitivity amongst isolates, followed by colistin with 50 % sensitivity. Three categories of resistance were found in these isolates: extreme drug resistance in 26, pan-drug resistance in 19 and multidrug resistance in 87 isolates. The isolates exhibited a high resistance to cephalosporins, trimethoprim-sulfamethoxazole and β-lactam antibiotics, followed by tetracycline and β-lactam/β-lactam inhibitor combination, fluoroquinolone and aminoglycosides. The results show a prominent level of antibiotic-resistance phenotypes in A. baumannii and strongly suggest the need for full-scale national surveillance of carbapenem-resistant A. baumannii with particular emphasis on the newly identified NDM-1 (New Delhi metallo-β-lactamase-1).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / epidemiology
  • Acinetobacter Infections / microbiology*
  • Acinetobacter baumannii / drug effects*
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / isolation & purification
  • Adolescent
  • Adult
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / genetics
  • Carbapenems / pharmacology*
  • Child
  • Cross Infection / epidemiology
  • Cross Infection / microbiology*
  • Female
  • Hospitals
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Pakistan / epidemiology
  • Young Adult
  • beta-Lactam Resistance*
  • beta-Lactamases / genetics

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Carbapenems
  • beta-Lactamases
  • carbapenemase