摘要
Klebsiella pneumoniae is an opportunistic pathogen, which causes a wide range of nosocomial infections. Recently, antibiotic resistance makes K. pneumoniae infection difficult to deal with. Investigation on virulence determinants of K. pneumoniae can provide more information about pathogenesis and unveil new targets for treatment or vaccine development. In this study, SitA, a Fur-regulated divalent cation transporter, was found significantly increased when K. pneumoniae was cultured in a nutrient-limited condition. A sitA-deletion strain (δ. sitA) was created to characterize the importance of SitA in virulence. δ. sitA showed higher sensitivity toward hydroperoxide than its parental strain. In a mouse intraperitoneal infection model, the survival rate of mice infected with δ. sitA strain increased greatly when compared with that of mice infected with the parental strain, suggesting that sitA deletion attenuates the bacterial virulence invivo. To test whether δ. sitA strain is a potential vaccine candidate, mice were immunized with inactivated bacteria and then challenged with the wild-type strain. The results showed that using δ. sitA mutant protected mice better than using the wild-type strain or the capsule-negative congenic bacteria. In summary, SitA was found being important for the growth of K. pneumoniae invivo and deleting sitA might be a potential approach to generate vaccines against K. pneumoniae. © 2013 Institut Pasteur.