Elsevier

Microbes and Infection

Volume 16, Issue 2, February 2014, Pages 161-170
Microbes and Infection

Original article
SitA contributes to the virulence of Klebsiella pneumoniae in a mouse infection model

https://doi.org/10.1016/j.micinf.2013.10.019Get rights and content
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Abstract

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 (ΔsitA) was created to characterize the importance of SitA in virulence. ΔsitA showed higher sensitivity toward hydroperoxide than its parental strain. In a mouse intraperitoneal infection model, the survival rate of mice infected with ΔsitA strain increased greatly when compared with that of mice infected with the parental strain, suggesting that sitA deletion attenuates the bacterial virulence in vivo. To test whether ΔsitA 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 ΔsitA 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 in vivo and deleting sitA might be a potential approach to generate vaccines against K. pneumoniae.

Keywords

Klebsiella pneumoniae
Virulence determinant
SitA
Vaccination
Mouse intraperitoneal infection

Abbreviations

cfu
colony-forming unit
CPS
capsule polysaccharide
2-D
two-dimensional
DMEM
Dulbecco's Modified Eagle's Medium
Kp K2044
Klebsiella pneumoniae strain NTUH-K2044
LB broth
Luria–Bertani broth
OMVs
outer membrane vesicles
Q-TOF
quadrupole time-of-flight

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