title: The role of pgaC in Klebsiella pneumoniae virulence and biofilm formation.
abstract: BACKGROUND
  Klebsiella pneumoniae has emerged as one of the major pathogens for community-acquired and nosocomial infections. A four-gene locus that had a high degree similarity with Escherichia coli pgaABCD and Yersinia pestis hmsHFRS was identified in K. pneumoniae genomes. The pgaABCD in E. coli encodes the envelope-spanning Pga machinery for the synthesis and secretion of poly-β-linked N-acetylglucosamine (PNAG). In a limited number of phylogenetically diverse bacteria, PNAG was demonstrated to mediate biofilm formation and had a role in the host-bacteria interactions. The presence of conserved pgaABCD locus among various K. pneumoniae strains suggested a putative requirement of PNAG for this bacterium.
  
  
  RESULTS
  In this study, an in-frame deletion of pgaC was generated in K. pneumoniae CG43 and named ΔpgaC. The loss of pgaC affected the production of PNAG and attenuated the enhancement of in vitro biofilm formation upon the addition of bile salts mixture. In mouse models, ΔpgaC exhibited a weakened ability to colonize the intestine, to disseminate extraintestinally, and to induce a systemic infection when compared to K. pneumoniae CG43.
  
  
  CONCLUSIONS
  Our study demonstrated that pgaC participated in the bile salts induced biofilm formation and was required for K. pneumoniae virulence in vivo.
authors.affiliation: Department of Infectious Disease, Antai Medical Care Cooperation Antai Tian-Sheng Memorial Hospital, Ping-tung, Taiwan, ROC. Electronic address: cowcutty@yahoo.com.tw.
authors.forename: Kuang-Ming
authors.initials: KM
authors.lastname: Chen
authors.affiliation: Department of Life Science, National Chung Cheng University, Chia-Yi, Taiwan, ROC. Electronic address: mkochiang@yahoo.com.
authors.forename: Ming-Ko
authors.initials: MK
authors.lastname: Chiang
authors.affiliation: Department of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC. Electronic address: wml@csmu.edu.tw.
authors.forename: Meilin
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Anatomy, Tzu Chi University, Hualien, Taiwan, ROC. Electronic address: hcho@mail.tcu.edu.tw.
authors.forename: Han-Chen
authors.initials: HC
authors.lastname: Ho
authors.affiliation: Department of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC; Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC. Electronic address: luminchi@csmu.edu.tw.
authors.forename: Min-Chi
authors.initials: MC
authors.lastname: Lu
authors.affiliation: Department of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC; Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC. Electronic address: yclai@csmu.edu.tw.
authors.forename: Yi-Chyi
authors.initials: YC
authors.lastname: Lai
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000235:genetics; D017353:Gene Deletion; D056426:Genetic Loci; D007710:Klebsiella Infections / Q000382:microbiology / Q000473:pathology; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D051379:Mice; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*; D015010:Yersinia pestis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors
keywords: Biofilm; Klebsiella pneumoniae; Poly-N-acetylglucosamine (PNAG); Virulence