title: The role of RND efflux pump and global regulators in tigecycline resistance in clinical Acinetobacter baumannii isolates.
abstract: OBJECTIVE
  To analyze the expression and regulation of resistance-nodulation-division (RND) efflux systems in clinical tigecycline-nonsusceptible (TNS) Acinetobacter baumannii.
  
  
  METHODS
  Comparisons of molecular and clinical characteristics were performed between 52 TNS and 53 tigecycline-susceptible isolates. Expression of RND efflux pumps and global regulators were analyzed by real-time RT-PCR. A complementation experiment was performed to evaluate the contribution of the adeRS mutations.
  
  
  RESULTS
  Mechanical ventilation and prior use of carbapenems were more common among patients with TNS strains. The relative expression of adeB and adeJ was increased significantly in TNS isolates. Complementarity to the adeR or adeS mutations decreased tigecycline susceptibility by ≤2-fold. Decreased expression of marR and soxR was detected in TNS isolates.
  
  
  CONCLUSIONS
  A correlation between tigecycline MIC and expression level of adeB and adeJ was identified. The influence of adeRS mutation on adeB expression was limited. Global regulators marR and soxR may be involved in tigecycline resistance.
authors: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors: Henan
authors: H
authors: Li
authors: Xiaojuan
authors: X
authors: Wang
authors: Yawei
authors: Y
authors: Zhang
authors: Chunjiang
authors: C
authors: Zhao
authors: Hongbin
authors: H
authors: Chen
authors: Sen
authors: S
authors: Jiang
authors: Feifei
authors: F
authors: Zhang
authors: Hui
authors: H
authors: Wang
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D005260:Female; D019450:Genes, MDR; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D017384:Sequence Deletion; D000078304:Tigecycline
chemical_list: C445684:AdeB protein, Acinetobacter baumannii; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D000078304:Tigecycline; D008911:Minocycline
keywords: Acinetobacter baumannii; adeB; adeRS; marR; soxR; tigecycline