Construction of hypervirulent Klebsiella pneumoniae strain with hfq gene deletion and study on its biological characteristics
10.3760/cma.j.cn112309-20220215-00045
- VernacularTitle:高毒力肺炎克雷伯菌 hfq基因缺失株的构建及其生物学特性分析
- Author:
Dandan WEI
1
;
Xiaoshun XIONG
;
Si CHEN
;
Qisen HUANG
;
Shanshan HUANG
;
Linping FAN
;
Yang LIU
Author Information
1. 南昌大学第一附属医院检验科，南昌 330006
- Keywords:
Hypervirulent Klebsiella pneumoniae;
hfq gene;
Homologous recombination;
Environmental adaptation
- From:
Chinese Journal of Microbiology and Immunology
2022;42(10):769-776
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To construct a mutant strain of hypervirulent Klebsiella pneumoniae NTHU-K2044 with hfq gene deletion and to analyze its biological characteristics. Methods:The hfq gene of NTUH-K2044 was knocked out by homologous recombination technology to construct △ hfq mutant strain. Its biological characteristics including growth rate, environmental stress tolerance, biofilm formation, capsular polysaccharide synthesis, resistance to neutrophil phagocytosis and lethality to Galleria mellonella larvae were analyzed by comparing with the wild-type strain using phenotypic experiments. Results:The △ hfq mutant strain of hypervirulent Klebsiella pneumoniae NTHU-K2044 was successfully constructed. Phenotypic experiments showed that the △ hfq mutant strain had significantly slower growth rate, smaller colonies and decreased hypermucoviscosity. Its growth was significantly inhibited under different environmental stress conditions such as pH9, pH5.5, 0.7 mmol/L SDS, 5% NaCl, 0.1% H 2O 2 and high temperature of 50℃. In terms of virulence and pathogenicity, the △ hfq mutant strain showed decreased ability to form biofilm and capsule, significantly down-regulated expression of magA and rmpA genes required for capsule synthesis, lower survival rate in the neutrophil bactericidal test and obviously reduced lethality to Galleria mellonella larvae. Conclusions:As a RNA chaperone, Hfq protein could participate in post-transcriptional regulation and play an important role in regulating the physiology, environmental adaptability and virulence of hypervirulent Klebsiella pneumoniae. This study provided reference for further study on hypervirulent Klebsiella pneumoniae.
