Zhang Meng, Liu Lizhang, Yang Xiaoqiang, Kang Yanhua, Qin Qiuying, Fu Yingying, Zhu Lin, Xu Yongchang
Zhejiang Key Laboratory of Medical Epigenetics, Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou 311121, China.
Department of Pharmacy, Second Clinical Medical College, Shanxi Medical University, Taiyuan, Shanxi 030001, China.
Sci Total Environ. 2025 Jan 1;958:177877. doi: 10.1016/j.scitotenv.2024.177877. Epub 2024 Dec 11.
The hospital setting serves as a critical conduit for pathogen dissemination, particularly amid the escalating concern of nosocomial infections in China. Currently, most studies use metagenomics to investigate microbial communities in hospital settings, with less focus on the transmission strategies of individual bacteria. In our study, we identified two Klebsiella pneumoniae strains exhibiting different mucoid characteristics. The strain designated as KPE was obtained from a well sanitized ward, while the strain KPH was isolated from the sputum samples of patients within the identical ward. We characterized the KPE strain as not lethal to mice and showed a distinct hypomuciod phenotype, strikingly different from the virulent KPH isolate. Two strains harbored the single nucleotide polymorphism (SNP) mutations in the virulence-related gene rmpA and wcaJ promoter regions, resulting in the downregulation of mucoid regulatory gene rmpA and capsule synthesis genes. Consequently, this led to diminished production of capsular polysaccharides and weakened virulence in the KPE strain. Furthermore, the KPE strain exhibited an elevated capacity for acquiring antibiotic-resistant plasmids and greater material survival ability. These findings indicated that mucoid changes enable K. pneumoniae strains to survive better on inanimate surfaces, promoting their persistence ward environment and further transmission in patients.
医院环境是病原体传播的关键渠道，在中国医院感染问题日益严重的情况下尤其如此。目前，大多数研究使用宏基因组学来调查医院环境中的微生物群落，而较少关注单个细菌的传播策略。在我们的研究中，我们鉴定出两株表现出不同黏液样特征的肺炎克雷伯菌菌株。命名为KPE的菌株取自一个清洁良好的病房，而KPH菌株则从同一病房患者的痰液样本中分离得到。我们将KPE菌株鉴定为对小鼠无致死性，并表现出明显的低黏液样表型，与具有毒性的KPH分离株显著不同。两株菌在毒力相关基因rmpA和wcaJ启动子区域存在单核苷酸多态性（SNP）突变，导致黏液样调节基因rmpA和荚膜合成基因下调。因此，这导致KPE菌株的荚膜多糖产量减少和毒力减弱。此外，KPE菌株获取抗生素耐药质粒的能力增强，物质存活能力更强。这些发现表明，黏液样变化使肺炎克雷伯菌菌株能够在无生命表面更好地存活，促进其在病房环境中的持续存在并在患者中进一步传播。
