|作者：||Niu Tianshui, Guo Lihua, Luo Qixia, Zhou Kai, Yu Wei, Chen Yunbo, Huang Chen, Xiao Yonghong|
1Collaborative Initiative Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis & Treatment of Infectious Diseases, the First Affiliated Hospital, college of Medicine, Zhejiang University, Hangzhou, China.
2Hangzhou Red Cross Hospital/Zhe Jiang Chinese Medcine and Western Medcine Integrated Hospital, Hangzhou, China.
3Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China.
|刊名：||Virulence, 2020, Vol.11 (1), pp.1-13|
|关键词：||Acinetobacter baumannii; Gene complementation; Gene knockout; Virulence; Wza;|
|原始语种摘要：||To investigate the virulence of capsular polysaccharide export protein (Wza) in carbapenem-resistant Acinetobacter baumannii and its effect on capsule formation. wza gene knockout and complementation strains were constructed, and changes in bacterial virulence were observed using in vitro adhesion, antiserum complement killing, anti-oxidation experiments, and infections in Galleria mellonella and mice. The effect of wza knockout on the genes wzb and wzc and wzi were assessed by RT-PCR.We successfully constructed wza knockout and complementation strains. Compared with wild-type (WT) strains, wza knockout strains displayed lower adhesion to A549 cells ( p = 0.044), lower antiserum complement killing ability ( p = 0.001), and lower mortality of G. mellonella ( p = 0.010) and mice ( p =... 0.033). Expression levels of wzb, wzc and wzi were decreased in wza knockout strains. The antioxidant capacity of Wza knockout bacteria was only slightly decreased. Complementation of the wza gene returned the adhesion ability, antiserum complement killing ability, and mortality of G. mellonella and mic e to WT levels. Expression of wzb, wzc and wzi was also returned to WT levels following wza complementation.The results clearly demonstrate that Wza is toxic. Wza affects the expression of othe r proteins of the Wzy capsule polysaccharide synthesis pathway, which affects the assembly, export, and extracellular fixation of capsular polysaccharide, resulting in synergistic effects that decrease bacterial virulence.|