Martone W J
National Foundation for Infectious Diseases, Bethesda, MD 20814, USA.
Infect Control Hosp Epidemiol. 1998 Aug;19(8):539-45. doi: 10.1086/647870.
The question of why vancomycin-resistant enterococci (VRE) became epidemic in the United States can be answered on at least three basic levels: (1) molecular and genetic, (2) factors affecting host-microbe interactions, and (3) epidemiological. This article will address the epidemiological issues and seek to defend the assertion that, once VRE had evolved, its spread throughout hospitals in the United States was all but assured. Nosocomial VRE outbreaks were reported first in the mid- and late-1980s. Since that time, scientific reports of VRE have increased over 20-fold. Among hospitals participating in the National Nosocomial Infection Surveillance System from 1989 to 1997, the percentage of enterococci reported as resistant to vancomycin increased from 0.4% to 23.2% in intensive-care settings and from 0.3% to 15.4% in non-intensive-care settings. Factors leading to the spread of VRE in US hospitals include (1) antimicrobial pressure, (2) sub-optimal clinical laboratory recognition and reporting, (3) unrecognized "silent" carriage and prolonged fecal carriage, (4) environmental contamination and survival, (5) intrahospital and interhospital transfer of colonized patients, (6) introduction of unrecognized carriers from community settings such as nursing homes, and (7) inadequate compliance with hand washing and barrier precautions. Guidelines developed by the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee address each of these factors. The impact of these guidelines on the spread of VRE within individual institutions has been variable, and the overall impact of the guidelines nationally is unknown.
耐万古霉素肠球菌（VRE）为何在美国流行这一问题至少可以从三个基本层面来回答：（1）分子和遗传学层面；（2）影响宿主 - 微生物相互作用的因素层面；（3）流行病学层面。本文将探讨流行病学问题，并试图论证这样一个观点，即一旦VRE进化出现，它在美国医院中的传播几乎是必然的。医院内VRE暴发最早在20世纪80年代中后期被报道。从那时起，关于VRE的科学报告增加了20多倍。在1989年至1997年参与国家医院感染监测系统的医院中，重症监护病房中报告对万古霉素耐药的肠球菌比例从0.4%升至23.2%，非重症监护病房中这一比例从0.3%升至15.4%。导致VRE在美国医院传播的因素包括：（1）抗菌压力；（2）临床实验室识别和报告不充分；（3）未被识别的“隐性”携带和长期粪便携带；（4）环境污染及存活；（5）定植患者在医院内和医院间的转移；（6）来自疗养院等社区环境的未被识别携带者的引入；（7）洗手和屏障预防措施的依从性不足。美国疾病控制与预防中心医院感染控制实践咨询委员会制定的指南针对了上述每一个因素。这些指南对单个机构内VRE传播的影响各不相同，其在全国范围内的总体影响尚不清楚。
