title: Identification of an immuno-dominant protein from Klebsiella pneumoniae strains causing pyogenic liver abscess: implication in serodiagnosis.
abstract: BACKGROUND
  Klebsiella pneumoniae has emerged worldwide as a cause of pyogenic liver abscess (PLA) often complicated by meningitis and endophthalmitis. Early detection of this infectious disease will improve its clinical outcome. Therefore, we tried to isolate immunodominant proteins secreted by K. pneumoniae strains causing PLA.
  
  
  RESULTS
  The secreted proteins of the NTUH-K2044 strain were separated by two-dimensional electrophoresis and then immunoblotted using convalescent sera from patients with K. pneumoniae PLA. A ~30-kDa immunodominant protein was then identified. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed an open reading frame (KP1_p307) located on the pK2044 plasmid and bioinformatic analysis identified this protein as a signal peptide of unknown function. The KP1_p307 gene was more prevalent in PLA strains and capsular type K1/K2 strains, but disruption of this gene in NTUH-K2044 strain did not decrease virulence in mice. Ten of fourteen (71%) sera from patients with K. pneumoniae PLA were immunoreactive with the recombinant KP1_p307 protein. Seroconversion demonstrated by a rise in serum titer in serial serum samples confirmed that antibodies against the KP1_p307 protein were elicited after infection.
  
  
  CONCLUSIONS
  The KP1_p307 protein could be used as an antigen for early serodiagnosis of K. pneumoniae PLA, particularly in K1/K2 PLA strains.
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, 1, Sec 1, Jen-Ai Rd., Taipei, Taiwan. f87445101@ntu.edu.tw.
authors.forename: Tzu-Lung
authors.initials: TL
authors.lastname: Lin
authors.affiliation: Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan. ypchuang@ndmctsgh.edu.tw.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Chuang
authors.affiliation: Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan. yutsunghuang@gmail.com.
authors.forename: Yu-Tsung
authors.initials: YT
authors.lastname: Huang
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, 1, Sec 1, Jen-Ai Rd., Taipei, Taiwan. peifanghsieh@yahoo.com.tw.
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Hsieh
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ytlin8@vghtpe.gov.tw.|School of Medicine, National Yang-Ming University, Taipei, Taiwan. ytlin8@vghtpe.gov.tw.
authors.forename: Yi-Tsung
authors.initials: YT
authors.lastname: Lin
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, 1, Sec 1, Jen-Ai Rd., Taipei, Taiwan. wangjt@ntu.edu.tw.|Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. wangjt@ntu.edu.tw.
authors.forename: Jin-Town
authors.initials: JT
authors.lastname: Wang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002853:Chromatography, Liquid; D019295:Computational Biology; D004195:Disease Models, Animal; D042241:Early Diagnosis; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D017353:Gene Deletion; D006801:Humans; D015151:Immunoblotting; D007710:Klebsiella Infections / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D007711:Klebsiella pneumoniae / Q000276:immunology* / Q000472:pathogenicity*; D046290:Liver Abscess, Pyogenic / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D016366:Open Reading Frames; D012698:Serologic Tests / Q000379:methods; D053719:Tandem Mass Spectrometry; D014774:Virulence; D037521:Virulence Factors / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D037521:Virulence Factors