一起纤维支气管镜污染所致感染暴发的分子流行病学调查

Molecular epidemiological survey on an infection outbreak due to contamination of fiberbronchoscope

摘要:

目的了解某院一起下呼吸道感染阴沟肠杆菌医院感染暴发的原因，为临床预防和控制医院感染提供依据。方法收集该院呼吸科与胸外科经纤维支气管镜肺泡灌洗诊疗发生下呼吸道阴沟肠杆菌感染患者的流行病学资料，对患者及其周围环境和物品检出菌进行耐药分析，采用脉冲场电泳（PFGE）技术进行基因分型。结果2013年3月8—16日胸外科与呼吸科在内镜中心纤维支气管镜室进行肺泡灌洗患者共15例，后续发生下呼吸道阴沟肠杆菌感染13例，经排查有4例为社区感染（包括首例患者），其余9例均为医院感染；8份环境标本检出2株阴沟肠杆菌，分别来源于纤维支气管镜负压吸引接头、用于修剪一次性可控式吸痰管道的剪刀。将患者与环境检测得到的阴沟肠杆菌15株进行药敏结果筛选，选出药敏结果相似的有11株菌，其中环境2株、住院患者6株、社区患者3株。11株阴沟肠杆菌PFGE分型显示，有8株菌基因型相同，其中6株来自于胸外科患者，2株来自于负压吸引接头与用于一次性可控式吸痰管道的剪刀；另3株基因型相同，来自于呼吸科与胸外科。结论此次感染暴发是由纤维支气管镜污染同一株阴沟肠杆菌引起，该菌对临床常用抗菌药物较敏感，此类事件应引起临床的高度重视，采用必要措施切断传播流行是控制关键。

Abstract:

ObjectiveTo investigate the causes of a healthcareassociated lower respiratory tract infection(HALRTI) outbreak due to Enterobacter cloacae(E. cloacae), and provide basis for clinical prevention and control of HAI. MethodsEpidemiological data of patients with E. cloacae HALRTI following bronchoalveolar lavage(BAL) in the departments of respiratory disease and thoracic surgery of a hospital were collected, antimicrobial resistance analysis on isolated pathogens from patients and environment was performed, pulsedfield gel electrophoresis (PFGE) was used for genotyping. ResultsOn March 8-16, 2013, a total of 15 patients underwent BAL in the fiberobronchoscopy room in the departments of respiratory disease and thoracic surgery of a hospital, 13 of whom developed E. cloacae LRTI, 4 cases were community-associated infection (the initial case was included), the other 9 cases were HAI; 8 environmental specimens were detected 2 strains of E. cloacae, the strains were from vacuum suction joint of fiberbronchoscope and scissors used for trimming disposable controllable sputum suction pipeline. 15 strains of E. cloacae from environment and patients were screened by antimicrobial susceptibility testing, 11 strains were with similar antimicrobial susceptibility testing result, 2 of which were environmental strains, 6 were from inpatients, and 3 were from patients in community. PFGE typing of 11 strains revealed that there were 8 strains with the same genotype, 6 of which were from patients in department of thoracic surgery, 2 were from vacuum suction joint of fiberbronchoscope and scissors used for disposable controllable sputum suction pipeline; the other 3 strains were of the same genotype, and from departments of respiratory disease and thoracic surgery. ConclusionThis outbreak is due to contamination of bronchofibroscope by the same E. cloacae strain, the strain is susceptible to the clinic commonly used antimicrobial agents, such events should be paid attention in clinic, the key to control infection is to take necessary measures for cutting off the spread of the epidemic.