Zhao Junhui, Zheng Beiwen, Xu Hao, Li Junfeng, Sun Tengfei, Jiang Xiawei, Liu Wenhong
School of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
Front Microbiol. 2022 Oct 20;13:980191. doi: 10.3389/fmicb.2022.980191. eCollection 2022.
Carbapenem-resistant (CRKP) seriously threaten the efficacy of modern medicine with a high associated mortality rate and unprecedented transmission rate. In this study, we isolated a clinical strain DY1928 harboring from a neonate with blood infection. Antimicrobial susceptibility testing indicated that DY1928 was resistant to various antimicrobial agents, including meropenem, imipenem, ceftriaxone, cefotaxime, ceftazidime, cefepime, piperacillin-tazobactam, and amoxicillin-clavulanate. S1 nuclease-pulsed field gel electrophoresis (S1-PFGE), southern blot and conjugation experiment revealed that the gene was located on a conjugative plasmid of IncA/C2 type with a 147.9 kb length. Whole-genome sequencing showed that there was a conservative structure sequence ( ---) located downstream of the gene. Multilocus sequence typing (MLST) classified DY1928 as ST25, which was a hypervirulent type. Phylogenetic analysis of genomic data from all ST25 strains available in the NCBI database suggested that all positive strains were isolated in China and had clinical origins. A mouse bloodstream infection model was constructed to test the virulence of DY1928, and 11 strains homologous to DY1928 were isolated from the feces of infected mice. Moreover, we found that DY1928 had a tendency to flow from the blood into the intestine in mice and caused multiple organ damage. To our knowledge, this is the first study to report an infection caused by -positive ST25 in the neonatal unit. Our findings indicated that stricter surveillance and more effective actions were needed to reduce the risk of disseminating such strains in clinical settings, especially in neonatal wards.
耐碳青霉烯类肺炎克雷伯菌（CRKP）以高相关死亡率和前所未有的传播率严重威胁着现代医学的疗效。在本研究中，我们从一名患有血液感染的新生儿中分离出一株临床菌株DY1928。抗菌药物敏感性测试表明，DY1928对多种抗菌药物耐药，包括美罗培南、亚胺培南、头孢曲松、头孢噻肟、头孢他啶、头孢吡肟、哌拉西林-他唑巴坦和阿莫西林-克拉维酸。S1核酸酶脉冲场凝胶电泳（S1-PFGE）、Southern印迹和接合实验表明，blaKPC基因位于一个长度为147.9 kb的IncA/C2型接合质粒上。全基因组测序显示，在blaKPC基因下游存在一个保守结构序列（---）。多位点序列分型（MLST）将DY1928分类为ST25，这是一种高毒力型。对NCBI数据库中所有可用的ST25菌株的基因组数据进行系统发育分析表明，所有blaKPC阳性菌株均在中国分离且具有临床来源。构建了小鼠血流感染模型以测试DY1928的毒力，并从感染小鼠的粪便中分离出11株与DY1928同源的菌株。此外，我们发现DY1928在小鼠体内有从血液流向肠道的趋势并导致多器官损伤。据我们所知，这是第一项报道新生儿病房中由blaKPC阳性ST25引起感染的研究。我们的研究结果表明，需要更严格的监测和更有效的措施来降低此类菌株在临床环境中传播的风险，尤其是在新生儿病房。
