Distribution of the multidrug efflux pump genes, adeABC, adeDE and adeIJK, and class 1 integron genes in multiple-antimicrobial-resistant clinical isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus complex

Int J Antimicrob Agents. 2009 Jan;33(1):27-32. doi: 10.1016/j.ijantimicag.2008.06.027. Epub 2008 Sep 13.


Of 112 non-repetitive clinical isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus complex, 80% were resistant to a variety of structurally unrelated antimicrobials although all isolates were susceptible to minocycline and polymyxin. Resistance to carbapenems occurred in 8% of the isolates. The presence of adeSR-adeABC, adeDE and adeIJK drug efflux system genes and class 1 integron genes (integrase gene int1) was assessed by polymerase chain reaction (PCR) in relation to the susceptibility of the isolates to 20 antimicrobials. The majority of isolates (75%) with high levels of multidrug resistance were positive for adeSR-adeABC and adeIJK as well as int1 and thus belong to A. baumannii (i.e. genomospecies 2). Positive adeE was only observed in adeSR-adeABC/adeIJK/int1-negative isolates (8%; likely belonging to Acinetobacter genomospecies 3) that were relatively susceptible to several agents, and adeE expression was undetectable. The results reveal a possible association between adeABC/adeIJK and int1 in multidrug-resistant isolates of A. baumannii. In addition, differential distribution of the resistance-nodulation-cell division (RND) genes can likely be used as indicators for differentiating Acinetobacter species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / microbiology
  • Acinetobacter baumannii / classification
  • Acinetobacter baumannii / drug effects*
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / metabolism
  • Acinetobacter calcoaceticus / classification
  • Acinetobacter calcoaceticus / drug effects*
  • Acinetobacter calcoaceticus / genetics
  • Acinetobacter calcoaceticus / metabolism
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Humans
  • Integrons / genetics*
  • Integrons / physiology
  • Membrane Transport Proteins / genetics*
  • Membrane Transport Proteins / metabolism
  • Microbial Sensitivity Tests


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Membrane Transport Proteins