title: Genomic heterogeneity in Klebsiella pneumoniae strains is associated with primary pyogenic liver abscess and metastatic infection.
abstract: BACKGROUND
  Primary pyogenic liver abscess (PLA) with septic complication by Klebsiella pneumoniae is an emerging infectious disease.
  
  
  RESULTS
  Using DNA microarray hybridization, we identified a 20-kb chromosomal region that contained 15 open-reading frames (ORFs), including an iron-uptake system (kfu), a phosphoenolpyruvate sugar phosphotransferase system (PTS), and 6 unknown ORFs. The region was more prevalent among tissue-invasive strains (35/46) than among noninvasive strains (19/98) (P<.0001, chi2 test). To test the role played by this region in pathogenesis, 3 different deletion mutants (NTUH-K2044 [Delta kfu], K2044 [Delta ORF7-9], and K2044 [Delta PTS]) were constructed. Only the Delta kfuABC mutants showed decreased virulence in mice, compared with the wild-type strain. An in vitro assay confirmed the involvement of kfu in iron acquisition. There was a high correlation rate (85%) between the kfu/PTS region and 2 tissue invasion-associated chromosomal regions (allS and magA). Moreover, all 3 regions were present in strains that caused PLA plus endophthalmitis or meningitis.
  
  
  CONCLUSIONS
  Our results suggest that chromosomal heterogeneity is present in tissue-invasive K. pneumoniae strains. A genotype containing all 3 regions is strongly associated with PLA and metastatic infection. These regions may serve as convenient markers for the rapid diagnosis of emergent tissue-invasive strains.
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Li-Chen
authors.initials: LC
authors.lastname: Ma
authors.forename: Chi-Tai
authors.initials: CT
authors.lastname: Fang
authors.forename: Cha-Ze
authors.initials: CZ
authors.lastname: Lee
authors.forename: Chia-Tung
authors.initials: CT
authors.lastname: Shun
authors.forename: Jin-Town
authors.initials: JT
authors.lastname: Wang
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D009877:Endophthalmitis / Q000382:microbiology; D014644:Genetic Variation; D016680:Genome, Bacterial; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000472:pathogenicity*; D046290:Liver Abscess, Pyogenic / Q000382:microbiology*; D016920:Meningitis, Bacterial / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D046228:Microarray Analysis; D010957:Plasmids; D018805:Sepsis / Q000382:microbiology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins