Samore M H, Venkataraman L, DeGirolami P C, Arbeit R D, Karchmer A W
Division of Infectious Diseases, New England Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
Am J Med. 1996 Jan;100(1):32-40. doi: 10.1016/s0002-9343(96)90008-x.
A prospective clinical and molecular epidemiologic study was conducted to define the frequency of nosocomial Clostridium difficile patient-to-patient transmission in an urban tertiary referral hospital.
Over a 6-month period, environmental cultures for C difficile were obtained from patients with new positive stool cytotoxin assay (index cases); stool samples were obtained from selected patient contacts (the roommate, occupants of adjacent rooms, and the patient occupying the index room after discharge of the index case); and hand cultures were obtained from personnel contacts. C difficile isolates were analyzed by pulse-field gel electrophoresis (PFGE) or, for isolates that were nontypeable by PFGE, by restriction enzyme analysis.
During the study period, we identified 98 index cases of C difficile toxin-associated diarrhea, including focal outbreaks on two wards totaling 26 cases within a 2-month interval. Environmental contamination was detected at > or = 1 sites in 58% of rooms and often involved wide dispersed areas. Among 99 prospectively identified patient contacts, C difficile was cultured from the stool of 31 (31%), including 12 with diarrhea and 19 who were asymptomatic. C difficile was cultured from the hands of 10 (14%) of 73 personnel. Molecular analysis resolved 31 typing profiles among the index isolates; the most common profile (designated strain D1) was represented by 30 isolates. Among the isolates from patient contacts, 5 of 12 from symptomatic contacts matched the corresponding index isolate, and only 1 of 19 from asymptomatically colonized contacts matched. Transmission to personnel or patient contacts of the strain cultured from the corresponding index case was correlated strongly with the intensity of environmental contamination. Strain D1 was frequently represented among isolates associated with heavy environmental contamination, with personnel carriage, and with development of symptomatic illness among prospectively identified contacts.
Intense environmental contamination and transmission to close personnel and patient contacts represented coordinated properties of an individual epidemic strain. For most epidemiologically linked contacts, positive cultures for C difficile did not result from transmission from the presumed index case.
开展一项前瞻性临床和分子流行病学研究，以确定一家城市三级转诊医院中艰难梭菌在患者之间的医院内传播频率。
在6个月期间，从新出现粪便细胞毒素检测呈阳性的患者（索引病例）中获取艰难梭菌环境培养样本；从选定的患者接触者（室友、相邻病房居住者以及索引病例出院后入住索引病房的患者）中获取粪便样本；从人员接触者中获取手部培养样本。通过脉冲场凝胶电泳（PFGE）对艰难梭菌分离株进行分析，对于PFGE无法分型的分离株，则通过限制性酶切分析进行分析。
在研究期间，我们确定了98例艰难梭菌毒素相关腹泻的索引病例，包括两个病房内的局部暴发，在2个月内共有26例。在58%的病房中，≥1个位点检测到环境污染，且污染区域往往广泛分散。在99名前瞻性确定的患者接触者中，31人（31%）的粪便培养出艰难梭菌，其中12人腹泻，19人无症状。在73名人员中，10人（14%）的手部培养出艰难梭菌。分子分析确定了索引分离株中的31种分型谱；最常见的谱型（指定为菌株D1）由30株分离株代表。在患者接触者的分离株中，有症状接触者的12株中有5株与相应的索引分离株匹配，无症状定植接触者的19株中只有1株匹配。从相应索引病例培养出的菌株传播给人员或患者接触者与环境污染程度密切相关。菌株D1在与严重环境污染、人员携带以及前瞻性确定的接触者中出现症状性疾病相关的分离株中经常出现。
严重的环境污染以及传播给密切接触的人员和患者是单一流行菌株的协同特性。对于大多数流行病学关联的接触者，艰难梭菌阳性培养并非来自假定的索引病例的传播。
