烧伤患者耐碳青霉烯类肺炎克雷伯菌感染的环境追踪研究

 目的 研究烧伤患者耐碳青霉烯类肺炎克雷伯菌（CRKP）感染与环境菌株的同源关系，为烧伤患者CRKP感染的防治提供科学依据。方法 前瞻性监测某院烧伤科重症监护病房（ICU）2020年6-12月的CRKP感染患者，进行临床标本与环境标本采样，通过Compact VITEK 2全自动微生物分析仪进行菌株鉴定和药物敏感试验。采用脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）进行菌株同源性分析，并检测毒力基因、荚膜血清型基因携带情况。结果 共有4例烧伤患者发生CRKP感染，2株分离自创面分泌物，2株分离自血。采集环境标本152份，经细菌鉴定和药物敏感试验，获得CRKP菌株共15株。通过PFGE分析，经聚类分析获得结果为A~G 7个聚类组，1号患者的血标本、2号患者的血标本及外环境标本及3号患者的创面分泌物及外环境标本具有同源性，为同一型别A型。将A~G型别的菌株进行MLST分析，结果分别得到A~G型为ST11、ST35、ST1、ST37、ST2929、ST23、ST17。对15株CRKP菌株进行毒力基因检测，5株K57型，ST型别为ST35、ST37和ST17。结论 烧伤患者环境CRKP检出率高，通过对环境标本追踪发现与临床标本分离菌株具有同源性，说明有效控制环境污染有助于防控感染传播扩散。CRKP出现局部克隆株流行，可能合并高毒力，下一步应开展更大范围的监测。

Tracing of the environment of burn patients infected with carbapenem-resistant Klebsiella pneumoniae

Objective To study the homologous relationship between the carbapenem-resistant Klebsiella pneumoniae (CRKP) in burn patients and the environmental bacterial strains, and provide scientific basis for the prevention and treatment of CRKP infection in burn patients. Methods Patients with CRKP infection from June to December 2020 in burn intensive care unit of a hospital were prospectively monitored. Clinical and environmental specimens were collected. Strains were identified and tested for antimicrobial susceptibility through Compact VITEK 2 automatic microbial analyzer. Homology of the strains were analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Carrying Status of virulence genes and capsular serotype genes were detected. Results A total of 4 burn patients developed CRKP infection, 2 strains were isolated from wound secretion and 2 from blood. 152 environmental specimens were collected, 15 CRKP strains were obtained after bacterial identification and antimicrobial susceptibility test. Cluster analysis through PFGE showed 7 cluster groups A-G. Blood specimens of patient 1, blood and environmental specimens of patient 2, as well as wound secretion and environmental specimens of patient 3 were homologous(all type A). Type A-G strains were analyzed by MLST, and showed that type A-G were ST11, ST35, ST1, ST37, ST2929, ST23, and ST17. Virulence genes of 15 CRKP strains were tested, out of which 5 strains were K57, with ST types of ST35, ST37 and ST17. Conclusion Detection rate of CRKP in the environment of burn patients is high. Strains isolated from environmental specimens were found homologous to that from clinical specimens, indicating that effective control of environmental contamination is conducive to the prevention and control of infection spread. In addition, CRKP exhibits prevalence of clone strains, which may combine with high virulence. More extensive monitoring should be carried out.