中文摘要：肺炎克雷伯菌是一种常见的院内感染机会致病菌。早期研究证明，耐粘菌素肺炎克雷伯菌比对粘菌素敏感的亲本株，包括T1样CYRILLIC CAPITAL LETTER EFNJS1，更易被溶尾噬菌体杀死。这种与粘菌素耐药性相关的适应是由于表面电荷的改变，促进了噬菌体附着和感染，但尚未识别噬菌体附着的受体。本研究发现CYRILLIC CAPITAL LETTER EFNJS1可特异性感染非粘液型肺炎克雷伯菌分离株，且噬菌体对耐黏菌素的非粘液型肺炎克雷伯菌细胞的加速附着是可逆的。进一步研究表明，细菌脂多糖可能参与了噬菌体的可逆附着，而荚膜多糖则会阻断噬菌体附着在细胞表面受体。耐粘菌素肺炎克雷伯菌的转座子突变表明，参与脂多糖O抗原合成的两个基因，wecA和wecG的突变显著降低了噬菌体的附着能力和感染效率。wzyE的失活缩短了O抗原链长度，增强了噬菌体的感染性。此外，外膜蛋白FepA的突变使噬菌体裂解速度减慢，提示FepA可能是CYRILLIC CAPITAL LETTER EFNJS1的不可逆受体。综上所述，CYRILLIC CAPITAL LETTER EFNJS1与其宿主之间存在着微妙平衡，脂多糖O抗原可能是噬菌体NJS1必需的可逆受体，而O抗原长链则阻碍了噬菌体的感染。
外文摘要：Klebsiella pneumoniae is an opportunistic pathogen commonly associated with nosocomial infections. In our previous study, we have demonstrated that colistin-resistant K. pneumoniae is more susceptible to killing by lytic tailed phages than the colistin-sensitive parent strain, including T1-like CYRILLIC CAPITAL LETTER EFNJS1. This fitness cost associated with colistin resistance is due to the alteration of the surface charge that promotes phage adherence and infection. However, the receptor for phage adsorption has not been identified. In this study, we found that CYRILLIC CAPITAL LETTER EFNJS1 specifically infected nonmucoid K. pneumoniae isolates, and the accelerated phage adsorption to colistin-resistant nonmucoid K. pneumoniae cells is reversible. Further research suggested that bacteria lipopolysaccharide may be involved in phage reversible adsorption, while capsule polysaccharide may block the receptors on cell surface from phage attachment. Transposon mutagenesis of colistin-resistant K. pneumoniae revealed that mutation in wecA and wecG, two genes involved in lipopolysaccharide O-antigen biosynthesis, significantly deceased phage adsorption capacity and infection efficiency. Inactivation of wzyE, which leaded to the shorten of O-antigen chain length, enhanced phage infectivity. Moreover, mutation of the outer membrane protein FepA slowed the phage lysis rate, suggesting that FepA may be an irreversible receptor for CYRILLIC CAPITAL LETTER EFNJS1. In summary, our results show a delicate balance between CYRILLIC CAPITAL LETTER EFNJS1 and its hosts, where the lipopolysaccharide O-antigen may serve as an essential reversible receptor for phage NJS1, while the long O-antigen chain hinders the bacteriophage infection.
外文关键词：Klebsiella pneumoniae；Nonmucoid；O-antigen；Lipopolysaccharide；Outer membrane protein；Phage receptor
作者：Hao, GJ；Yuan, CQ；Shu, RD；Jia, YQ；Zhao, SQ；Xie, SJ；Liu, M；Zhou, HJ；Sun, SH；Wang, H
作者单位：Nanjing Agr Univ；Chinese Ctr Dis Control & Prevent；Shandong Agr Univ
期刊名称：MICROBIAL PATHOGENESIS
期刊影响因子：2.914
出版年份：2021
出版刊次：155
点击下载：O抗原是噬菌体NJS1感染非粘液型肺炎克雷伯菌的双面宿主因子