title: Virulence characteristics of Klebsiella and clinical manifestations of K. pneumoniae bloodstream infections.
abstract: We studied 455 consecutive episodes of Klebsiella pneumoniae bacteremia occurring in 7 countries. Community-acquired pneumonia and an invasive syndrome of liver abscess, meningitis, or endophthalmitis occurred only in Taiwan and South Africa. Infections by K1 and K2 capsular serotype, the mucoid phenotype, and aerobactin production were important determinants of virulence. The mucoid phenotype was seen in 94% of isolates in patients with community-acquired pneumonia and in 100% of isolates that caused the invasive syndrome in Taiwan and South Africa, compared with only 2% of isolates elsewhere. Mortality of mice injected with mucoid strains (69%) was strikingly higher than that occurring in mice injected with nonmucoid strains (3%, p < 0.001). Differences in clinical features of bacteremic infection with K. pneumoniae are due to the virulence factors expressed by the organism.
authors.affiliation: *University of Pittsburgh, Pittsburgh, Pennsylvania, USA. vly@pitt.edu
authors.forename: Victor L
authors.initials: VL
authors.lastname: Yu
authors.forename: Dennis S
authors.initials: DS
authors.lastname: Hansen
authors.forename: Wen Chien
authors.initials: WC
authors.lastname: Ko
authors.forename: Asia
authors.initials: A
authors.lastname: Sagnimeni
authors.forename: Keith P
authors.initials: KP
authors.lastname: Klugman
authors.forename: Anne
authors.initials: A
authors.lastname: von Gottberg
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Wagener
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Benedi
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D016667:Bacterial Capsules; D001681:Biological Assay; D017714:Community-Acquired Infections; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D007711:Klebsiella pneumoniae / Q000145:classification / Q000472:pathogenicity*; D008100:Liver Abscess / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D016920:Meningitis, Bacterial / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D011135:Polysaccharides, Bacterial; D011446:Prospective Studies; D012307:Risk Factors; D012703:Serotyping; D013019:South Africa / Q000453:epidemiology; D013624:Taiwan / Q000453:epidemiology; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial; C036962:capsular polysaccharide K1; C068924:capsular polysaccharide K2