title: The sensor kinase BfmS mediates virulence in Acinetobacter baumannii.
abstract: OBJECTIVE
  BfmR, the response regulator component of the two-component system BfmRS, has important roles in biofilm formation and cellular morphology of Acinetobacter baumannii. Until now, the contribution of the sensor kinase BfmS to the virulence of this bacterium remains unknown. In this study, a bfmS knockout and complementation studies were performed to clarify the role of BfmS in A. baumannii virulence.
  
  
  METHODS
  We constructed a bfmS knockout mutant in the A. baumannii 17978 type strain by transposon inactivation. To clarify the role of bfmS in A. baumannii virulence, the biofilm formation, adherence ability to eukaryotic cells, serum resistance, and antibiotic susceptibility tests were performed in A. baumannii 17978 and its derivative knockout and complementation strains.
  
  
  RESULTS
  The bfmS knockout displayed a reduction in biofilm formation, loss of adherence to eukaryotic cells, and greater sensitivity to serum killing compared with the parent strain. Proteomic analysis of culture supernatants revealed that the release of outer membrane proteins (Omps), including CarO and outer membrane protein A (OmpA), was associated with the inactivation of BfmS in A. baumannii.
  
  
  CONCLUSIONS
  This study is the first to demonstrate that the pathway regulated by the sensor kinase BfmS is associated with biofilm formation, adherence to biotic surfaces, serum resistance, and antibiotic susceptibility, which may be associated with the release of Omps in A. baumannii.
authors: Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsin-Chu City, Taiwan; Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan.
authors: Ming-Li
authors: ML
authors: Liou
authors: Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan.
authors: Po-Chi
authors: PC
authors: Soo
authors: Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan.
authors: Siao-Ru
authors: SR
authors: Ling
authors: Department of Medicine, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chu City, Taiwan; School of Medicine, National Yang-Ming University, New Taipei City, Taiwan.
authors: Han-Yueh
authors: HY
authors: Kuo
authors: Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan.
authors: Chuan Yi
authors: CY
authors: Tang
authors: Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan; Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan. Electronic address: kaichih@mail.tcu.edu.tw.
authors: Kai-Chih
authors: KC
authors: Chang
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms; D002460:Cell Line; D056426:Genetic Loci; D059765:Homologous Recombination; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D040901:Proteomics; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D011494:Protein Kinases
keywords: Acinetobacter baumannii; BfmS; Virulence