title: [Role of the AdeABC efflux pump in carbapenems resistance of clinical isolates of Acinetobacter baumannii].
abstract: OBJECTIVE
  To investigate the role of AdeABC efflux pump in carbapenems resistance of Acinetobacter baumannii in light of the phenotype and genetype of the efflux pump.
  
  
  METHODS
  The phenotype of the efflux pump was detected in 138 clinical isolates of A.baumannii using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP). The mRNA expression of pump-encoding gene adeB in the strains was detected using quantitative real-time RT-PCR.
  
  
  RESULTS
  Of the 138 strains, 28 showed positivities for AdeABC efflux pump identified by Mueller-Hinton Broth with CCCP. Of the 39 strains resistant to meropenem, 15 (38.4%) showed positive results in CCCP assay, a rate significantly higher than that among the 99 sensitive strains (13.1%, 13/99) (X(2)=12.477(b), P=0.01). The mRNA expression of efflux pump-encoding gene adeB was detected by real-time RT-PCR at a level of 0.899∓∓1.172 in meropenem-sensitive strains, significantly lower than the level of 21.101∓∓21.443 in meropenem-resistant strains (t=4.403, P=0.000).
  
  
  CONCLUSIONS
  Efflux plays a role in carbapenems resistance in the clinical isolates of A. baumannii. The AdeABC efflux pump may be an important factor in reducing carbapenems sensitivity in A. baumannii.
authors.affiliation: Department of Respiratory Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen 518116, China. mazhen01@21cn.com
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ma
authors.forename: Shao-xi
authors.initials: SX
authors.lastname: Cai
authors.forename: Wan-cheng
authors.initials: WC
authors.lastname: Tong
authors.forename: Shi-chong
authors.initials: SC
authors.lastname: Ruan
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015780:Carbapenems / Q000494:pharmacology*; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018440:beta-Lactam Resistance / Q000235:genetics*
chemical_list: C492436:AdeA protein, Acinetobacter baumannii; C445684:AdeB protein, Acinetobacter baumannii; C492437:AdeC protein, Acinetobacter baumannii; D001426:Bacterial Proteins; D015780:Carbapenems; D026901:Membrane Transport Proteins