Department of Clinical Laboratory, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China.
State Key Lab of Chemical Biology and Drug Discovery and the Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Department of Medical Microbiology, School of Biology and Basic Medical Science, Medical College of Soochow University, Suzhou, China; Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Soochow University, Suzhou, China.
Sci Total Environ. 2023 Sep 1;889:164302. doi: 10.1016/j.scitotenv.2023.164302. Epub 2023 May 19.
Klebsiella pneumoniae has evolved into strains of various phenotypes that pose a grave threat to human health in the past few decades. This study investigated a novel morphotype of K. pneumoniae with enhanced adaption to the hospital environment. Clinical K. pneumoniae were characterized by different genotypic and phenotypic tests. Gene knockout and complementation experiments were used to confirm the genetic changes that led to the morphological changes. ST15 carbapenem-resistant and hypervirulent (CR-hvKP) clinical strains with the "red, dry and rough" (rdar) morphotype were increasingly detected in hospitals in China. Strains with the rdar phenotype were found to be less virulent compared with that with typical morphologies but exhibit enhanced ability to adhere to the surface of various materials, and hence a dramatically increased rate of survival on various materials commonly found in the hospital environment. Comparative genomics analysis and gene function studies suggested the rdar morphotype was due to a GD substitution in the BcsA protein which enabled the strain to produce a large amount of cellulose. These findings show evolutional phenotypic change enables K. pneumoniae strains to better survive both in human and hospital environments, facilitating its persistence and further dissemination.
在过去的几十年中，肺炎克雷伯菌已经进化为具有各种不同表型的菌株，对人类健康构成了严重威胁。本研究调查了一种新型肺炎克雷伯菌形态，其对医院环境的适应性更强。通过不同的基因型和表型测试对临床分离株肺炎克雷伯菌进行了特征描述。基因敲除和互补实验用于确认导致形态变化的遗传变化。在中国的医院中，越来越多地检测到具有“红、干、糙”（rdar）形态的耐碳青霉烯和超毒力（CR-hvKP）临床菌株。与典型形态相比，rdar 表型菌株的毒力较低，但表现出更强的粘附各种材料表面的能力，因此在医院环境中常见的各种材料上的存活率显著增加。比较基因组学分析和基因功能研究表明，rdar 形态是由于 BcsA 蛋白中的 GD 取代，使该菌株能够产生大量纤维素。这些发现表明，表型的进化变化使肺炎克雷伯菌菌株能够更好地在人类和医院环境中存活，从而促进其持续存在和进一步传播。
