Fortún Jesús, Coque Teresa M, Martín-Dávila Pilar, Moreno Leonor, Cantón Rafael, Loza Elena, Baquero Fernando, Moreno Santiago
Department of Infectious Diseases, Ramón y Cajal Hospital, University of Alcalá, Crtra Colmenar Km 9.1, Madrid 28034, Spain.
J Antimicrob Chemother. 2002 Dec;50(6):1003-9. doi: 10.1093/jac/dkf216.
Epidemiological characteristics of ampicillin-resistant, vancomycin-susceptible Enterococcus faecium are not well known. Recently, these strains have been proposed as the substratum for the later appearance of vancomycin-resistant E. faecium. To analyse this problem, the medical charts of patients with bacteraemia caused by E. faecium diagnosed in our institution during a 6 year period (1994-1999) were reviewed. Demographic data, clinical characteristics, antibiotic exposure and outcome were compared among patients with ampicillin-resistant (MIC > 16 mg/L, NCCLS criteria) and ampicillin-susceptible strains. Clonality between different strains was analysed by pulsed-field gel electrophoresis (PFGE). We evaluated 49 cases of E. faecium bacteraemia; 29 patients with ampicillin-resistant strains and 20 patients with -susceptible strains were identified. By logistic regression analysis, only previous administration of beta-lactams (OR: 6.3; 95% CI: 1.12-20.0) and urinary catheterization (OR:4.2; 95% CI: 1.3-30.0) were identified as predictors of ampicillin resistance in enterococcal bacteraemic patients. An elevated APACHE II score was the only independent factor associated with mortality in enterococcal bacteraemia (OR:13.5; 95% CI: 1.04-175.4). PFGE analysis revealed a strong association between specific ampicillin-resistant clones and the location of patients during hospitalization, suggesting nosocomial transmission. Bacteraemia caused by ampicillin-resistant enterococci was not associated with increased mortality when compared with bacteraemias caused by ampicillin-susceptible strains.
耐氨苄西林、对万古霉素敏感的粪肠球菌的流行病学特征尚不清楚。最近，这些菌株被认为是随后出现的耐万古霉素粪肠球菌的基础菌株。为分析这一问题，我们回顾了本机构在6年期间（1994 - 1999年）诊断为粪肠球菌菌血症患者的病历。比较了耐氨苄西林（最低抑菌浓度＞16mg/L，符合美国国家临床实验室标准化委员会标准）和氨苄西林敏感菌株患者的人口统计学数据、临床特征、抗生素暴露情况及转归。通过脉冲场凝胶电泳（PFGE）分析不同菌株之间的克隆性。我们评估了49例粪肠球菌菌血症病例；确定了29例感染耐氨苄西林菌株的患者和20例感染敏感菌株的患者。通过逻辑回归分析，仅先前使用β - 内酰胺类药物（比值比：6.3；95%置信区间：1.12 - 20.0）和导尿（比值比：4.2；95%置信区间：1.3 - 30.0）被确定为肠球菌菌血症患者氨苄西林耐药的预测因素。APACHE II评分升高是肠球菌菌血症患者死亡的唯一独立相关因素（比值比：13.5；95%置信区间：1.04 - 175.4）。PFGE分析显示特定的耐氨苄西林克隆与患者住院期间的位置之间存在密切关联，提示医院内传播。与氨苄西林敏感菌株引起的菌血症相比，耐氨苄西林肠球菌引起的菌血症与死亡率增加无关。
