中文摘要：肺炎克雷伯菌是一种机会性病原体，对全球公共卫生构成严重威胁，而荚膜是肺炎克雷伯菌感染和毒力所必需。噬菌体源性荚膜解聚酶在治疗碳青霉烯类耐药肺炎克雷伯菌（CRKP）感染方面显示出巨大的潜力。然而，编码抗CRKP解聚酶的噬菌体治疗潜力仍知之甚少。本研究鉴定了一种长尾噬菌体SRD2021，对粘液型CRKP具有特异性，该CRKP为荚膜K47血清型，是亚洲主要的感染性K型。基因组测序显示，phi SRD2021属于核果病毒属，在其尾部纤维蛋白中有一个荚膜解聚酶结构域。为鉴定phi SRD2021的受体，构建了宿主细菌的转座子插入文库。研究发现，大多数噬菌体抗性突变体转化为非粘液型，包括荚膜多糖输出所必需的wza基因突变体。进一步的敲除和互补实验证实，δwza突变体避免了phi SRD2021的吸附，表明K47荚膜多糖是噬菌体感染的必要受体。在mellonella Galleria模型中，phi SRD2021裂解细菌成熟的生物膜，对预防和治疗CRKP感染具有治疗效果。此外，phi SRD2021还显著降低了小鼠肠道定植的CRKP。可见，通过识别宿主荚膜为受体，phi SRD2021可作为K47血清型肺炎克雷伯菌感染的潜在抗菌剂。
外文摘要：Klebsiella pneumoniae is an opportunistic pathogen posing an urgent threat to global public health, and the capsule is necessary for K. pneumoniae infection and virulence. Phage-derived capsule depolymerases have shown great potential as antivirulence agents in treating carbapenem-resistant K. pneumoniae (CRKP) infections. However, the therapeutic potential of phages encoding depolymerases against CRKP remains poorly understood. In this study, we identified a long-tailed phage SRD2021 specific for mucoid CRKP with capsular K47 serotype, which is the predominant infectious K-type in Asia. Genome sequencing revealed that phi SRD2021 belonged to the Drulisvirus genus and exhibited a capsular depolymerase domain in its tail fiber protein. A transposon-insertion library of host bacteria was constructed to identify the receptor for phi SRD2021. We found that most phage-resistant mutants converted to a nonmucoid phenotype, including the mutant in wza gene essential for capsular polysaccharides export. Further knockout and complementation experiments confirmed that the Delta wza mutant avoided adsorption by phi SRD2021, indicating that the K47 capsular polysaccharide is the necessary receptor for phage infection. phi SRD2021 lysed the bacteria mature biofilms and showed a therapeutic effect on the prevention and treatment of CRKP infection in the Galleria mellonella model. Furthermore, phi SRD2021 also reduced the colonized CRKP in mouse intestines significantly. By recognizing the host capsule as a receptor, our results showed that phi SRD2021 may be used as a potential antibacterial agent for K47 serotype K. pneumoniae infections.
外文关键词：Klebsiella pneumoniae；capsular polysaccharide；K47 serotype；phage receptor；phage therapy
作者：Hao, GJ；Shu, RD；Ding, LQ；Chen, X；Miao, YH；Wu, JQ；Zhou, HJ；Wang, H
作者单位：Nanjing Agr Univ；Shandong Agr Univ；Peking Univ；Chinese Ctr Dis Control & Prevent
期刊名称：ANTIBIOTICS-BASEL
期刊影响因子：3.893
出版年份：2021
出版刊次：8
点击下载：识别荚膜多糖的噬菌体SRD2021具有治疗血清型K47肺炎克雷伯菌感染的潜力