Toye B, Shymanski J, Bobrowska M, Woods W, Ramotar K
Department of Pathology and Laboratory Medicine, Ottawa General Hospital, University of Ottawa, Ontario, Canada.
J Clin Microbiol. 1997 Dec;35(12):3166-70. doi: 10.1128/jcm.35.12.3166-3170.1997.
Constitutive low-level vancomycin resistance is found intrinsically in certain enterococcal species and is encoded by vanC ligase genes. These intrinsically vancomycin-resistant enterococci (VRE) will be referred to as VANC VRE. A prospective study to determine the clinical and epidemiologic significance of VANC VRE was conducted. VANC VRE were recovered from the stools of 34 of 601 (5.7%) patients, a rate similar to that obtained for the stools of 100 outpatients in the community (5%). VANC VRE were also isolated from the nonstool specimens of 9 of 538 patients (1.7%), including two patients with bacteremia. No VRE of the vanA or vanB genotypes were detected in nonstool specimens. Eighty-two hospital contacts of the first 23 patients found to be colonized or infected with VANC VRE were screened, and 6 contacts were found to be gastrointestinal carriers of VANC VRE. However, typing of isolates from these 6 contacts by pulsed-field gel electrophoresis with SmaI showed the isolates to be unique and different from those recovered from the index patients. In fact, all VANC VRE isolates from different patients in this study were unique. A case-control study with patients who were negative when screened for VANC VRE as controls failed to identify any risk factor associated with colonization or infection with this organism. VANC VRE were infrequently recovered from clinical specimens but were occasionally found as part of the normal stool flora. Since no transmission between patients was documented, additional isolation procedures may not be necessary for patients colonized or infected with VANC VRE.
某些肠球菌属细菌本身就存在组成型低水平万古霉素耐药性，由vanC连接酶基因编码。这些固有万古霉素耐药肠球菌（VRE）将被称为VANC VRE。开展了一项前瞻性研究，以确定VANC VRE的临床和流行病学意义。从601例患者中的34例（5.7%）粪便中分离出VANC VRE，这一比例与100名社区门诊患者粪便中分离出VRE的比例（5%）相似。还从538例患者中的9例（1.7%）非粪便标本中分离出VANC VRE，其中包括2例菌血症患者。在非粪便标本中未检测到vanA或vanB基因型的VRE。对最初发现感染或定植VANC VRE的23例患者的82名医院接触者进行了筛查，发现6名接触者是VANC VRE的胃肠道携带者。然而，用SmaI脉冲场凝胶电泳对这6名接触者的分离株进行分型显示，这些分离株是独特的，与从索引患者中分离出的菌株不同。事实上，本研究中来自不同患者的所有VANC VRE分离株都是独特的。一项病例对照研究以筛查VANC VRE呈阴性的患者作为对照，未能确定与该菌定植或感染相关的任何危险因素。VANC VRE很少从临床标本中分离出来，但偶尔会在正常粪便菌群中发现。由于未记录到患者之间的传播，对于定植或感染VANC VRE的患者，可能无需采取额外的隔离措施。
