血液肿瘤患者耐碳青霉烯类肺炎克雷伯菌医院获得性血流感染疑似暴发调查与控制

Investigation and control of a suspected outbreak of carbapenem-resistant Klebsiella pneumoniae bloodstream infection in patients with hematological tumors

目的 对一起耐碳青霉烯类肺炎克雷伯菌(CRKP)医院获得性血流感染疑似暴发事件进行追踪调查,为有效控制CRKP感染提供依据。方法 于2022年6月在某教学医院成人血液科运用现场流行病学调查获取CRKP感染患者特征及造成事件传播的危险因素,采用血营养琼脂培养基现场接种法对病区进行环境采样寻找目标菌(CRKP),比较采取控制措施后环境微生物清除状况及感染控制效果。结果 CRKP造成的医院获得性血流感染共6例,罹患率1.29%(6/464),与2021年同期(0)相比增高,差异有统计学意义(P=0.011)。环境卫生学监测中,CRKP检出率为2.27%(1/44),来自感染患者居住床单元床帘表面,与2例患者检出的CRKP进行同源性分析发现,3株CRKP的16s RNA完全相同,相似度100%;3株CRKP的7个管家基因均相同,均属ST11型。采取综合控制措施:适当关闭病区、集中隔离患者、病区终末消毒、固定医务人员并相对限制其活动区域,采取措施后病区微生物菌落数合格率较采取措施前提高(2.27%VS 68.89%),差异有统计学意义(P<0.001),且干预后未再出现CRKP感染病例,控制措施有效。结论 本次暴发事件由我国常见CRKP中的ST11型引起,层流床床帘是病原菌传播的载体。推测清洁消毒不规范、手卫生执行不到位是传播的主要原因。而采用适当关闭病区策略、集中隔离患者能快速有效阻止传播蔓延。

Objective To investigate a suspected outbreak of carbapenem-resistant Klebsiella pneumoniae(CRKP)healthcare-associated bloodstream infection(HA-BSI),provide reference for effective control of CRKP infection.Methods The characteristics of CRKP infected patients and the risk factors for the event transmission in an adult hematology department of a teaching hospital in June 2022 were obtained by field epidemiological investigation.The specimens of environmental target strains were co-llected by blood nutrient agar inoculation,the removal status of environmental microorganisms and the effect of infection control after implementing control measures were compared.Results There were a total of 6 cases of CRKP HA-BSI,with an attacking rate of 1.29%(6/464),which was significantly higher than 0 during the same period in 2021,and difference was statistically significant(P=0.011).In environmental hygiene monitoring,the detection rate of CRKP was 2.27%(1/44),which was from the surface of bed curtain in the living unit of infected patients,homology analysis with CRKP detected from 2 patients revealed that the 16s RNA of 3 CRKP strains was completely identical,with a similarity of 100%.Seven housekeeping genes of 3 CRKP strains were all identical and belonged to the ST11 type.Comprehensive control measures were taken:appropriate closure of the ward,centralized isolation of patients,terminal disinfection of the ward,regular health care workers and relative restriction of their activity areas.After the measures were taken,the qualified rate of microbial colony count in the ward increased compared to before taking the measures(2.27%vs 68.89%,P<0.001),with a statistically significant difference,there were no more CRKP infected cases after the intervention,indicating that the control measures were effective.Conclusion This outbreak was caused by ST11 type of common CRKP in China,and laminar bed curtains are carriers of pathogen transmission.It is speculated that non-standard cleaning and disinfection,as well as inadequate implementation of hand hygiene are the main causes for transmission.Adopting an appropriate strategy of closing the ward and concentrating patient isolation can quickly and effectively prevent the transmission of the event.