Clinical and microbiological characteristics of Klebsiella pneumoniae isolates causing community-acquired urinary tract infections
- 561 Downloads
Klebsiella pneumoniae is the second most common species causing urinary tract infections (UTI). However, the host factors and virulence genes of K. pneumoniae related to UTI are poorly understood. The aim of this study was to analyze the capsular phenotype and virulence genes of K. pneumoniae isolates and host factors potentially relevant to community-acquired UTI.
Fifty-four K. pneumoniae isolates from patients with community-acquired UTI, 76 isolates from healthy adults, and 29 from patients with community-acquired pneumonia were compared. The virulence genes (rmpA, magA, uge, and wabG) and serotype (K1, K2, K5, K20, K54, or K57) were characterized by polymerase chain reaction (PCR). The modified string test was used to determine the hypermucoviscosity.
Diabetes mellitus was the most frequent underlying disease among UTI patients (53.7%, 29/54). No predominant K serotype was found in UTI strains. The hypermucoviscosity phenotype and rmpA gene were more often found in UTI isolates than in those from healthy adults (27.8 vs. 2.6%, P < 0.01; 29.6 vs. 11.8%, P < 0.01, respectively), whereas no significant difference in the frequency of magA, uge, wabG, or serotype genes was found. The prevalence of rmpA was significantly lower in isolates from patients with immunosuppression, chronic renal insufficiency, and urinary tract obstruction. Multivariate analysis showed that immunosuppression was negatively associated with the prevalence of rmpA.
Hypermucoviscosity was highly correlated with the presence of the rmpA gene in UTI strains, and rmpA may have a role in community-acquired UTI, especially in hosts without immunosuppression.
KeywordsUrinary tract infection Hypermucoviscosity Klebsiella pneumoniae Virulence factor
We are very grateful to Robert M. Jonas for his helpful comments on the manuscript. This work was supported in part by grants NSC97-2311-B-006-004-MY3 and NSC96-2320-B-006-008 from the National Science Council and by grant NCKUH-9804021 from the National Cheng-Kung University Hospital, Taiwan.
Conflict of interest
- 9.Ko WC, Paterson DL, Sagnimeni AJ, Hansen DS, Von Gottberg A, Mohapatra S, Casellas JM, Goossens H, Mulazimoglu L, Trenholme G, Klugman KP, McCormack JG, Yu VL. Community-acquired Klebsiella pneumoniae bacteremia: global differences in clinical patterns. Emerg Infect Dis. 2002;8:160–6.CrossRefPubMedGoogle Scholar
- 20.Farmer JJ III. Enterobacteriaceae: introduction and identification. In: Murray PR, Baron EJ, Pfaller MA, Tenover FC, Yolken RH, editors. Manual of clinical microbiology. Washington: American Society for Microbiology; 2007. p. 438–49.Google Scholar
- 23.Struve C, Bojer M, Nielsen EM, Hansen DS, Krogfelt KA. Investigation of the putative virulence gene magA in a worldwide collection of 495 Klebsiella isolates: magA is restricted to the gene cluster of Klebsiella pneumoniae capsule serotype K1. J Med Microbiol. 2005;54:1111–3.CrossRefPubMedGoogle Scholar
- 30.Tsay RW, Siu LK, Fung CP, Chang FY. Characteristics of bacteremia between community-acquired and nosocomial Klebsiella pneumoniae infection: risk factor for mortality and the impact of capsular serotypes as a herald for community-acquired infection. Arch Intern Med. 2002;162:1021–7.CrossRefPubMedGoogle Scholar
- 31.Yu VL, Hansen DS, Ko WC, Sagnimeni A, Klugman KP, von Gottberg A, Goossens H, Wagener MM, Benedi VJ; International Klebseilla Study Group. Virulence characteristics of Klebsiella and clinical manifestations of K. pneumoniae bloodstream infections. Emerg Infect Dis. 2007;13:986–93.PubMedGoogle Scholar
- 33.Wiselka MJ. Bacterial and host factors in the pathogenesis of UTI. In: Cattell WR, editor. Infections of the kidney and urinary tract. New York: Oxford University Press; 1996. p. 1597–654.Google Scholar