Marchaim Dror, Navon-Venezia Shiri, Schwaber Mitchell J, Carmeli Yehuda
Division of Epidemiology, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv 64239, Israel.
Antimicrob Agents Chemother. 2008 Apr;52(4):1413-8. doi: 10.1128/AAC.01103-07. Epub 2008 Jan 28.
The prevalence of isolation of imipenem-resistant Enterobacter (IRE) strains is rising, with potential serious consequences in terms of patients' outcomes and general care. The study objective was to define the various epidemiological aspects of the isolation of these strains in comparison to cases of isolation of imipenem-susceptible Enterobacter (ISE) strains. Molecular analysis of IRE strains included genotyping and defining the presence of carbapenemases. We conducted a matched retrospective case-control study of patients hospitalized from April 2003 to December 2006. Each IRE case was matched with an ISE case by age and source of isolation. A multivariate analysis using conditional logistic regression was performed to compare the two patient groups. There were 33 cases of IRE isolations during the study period. Twenty isolates were analyzed and found to belong to three distinct pulsotypes. Cell extracts of all of these isolates hydrolyzed imipenem. PCR and sequencing revealed that these isolates harbored a KPC-2 gene. In multivariate analysis, a high invasive-device score (P = 0.02) remained a predictor of IRE isolation. The mortality in the IRE group was 33%, compared to 9% among controls. Being an IRE case was significantly associated with increased mortality after controlling for confounders in a multivariate model (odds ratio, 8.3 +/- 8.6; 95% confidence interval, 1.07 to 64; P = 0.043). Resistance to imipenem due to bla(KPC-2) among Enterobacter isolates has occurred in several clones in Tel Aviv, affecting particularly patients with multiple invasive devices compared to ISE controls. IRE infections are associated with increased mortality. Enhanced measures to control the hospital spread of IRE are warranted.
耐亚胺培南肠杆菌（IRE）菌株的分离率正在上升，这对患者的治疗结果和整体护理可能产生严重后果。本研究的目的是确定这些菌株分离的各种流行病学特征，并与耐亚胺培南肠杆菌（ISE）菌株的分离情况进行比较。对IRE菌株的分子分析包括基因分型和确定碳青霉烯酶的存在情况。我们对2003年4月至2006年12月住院的患者进行了一项匹配的回顾性病例对照研究。每个IRE病例按年龄和分离源与一个ISE病例进行匹配。使用条件逻辑回归进行多变量分析，以比较两组患者。在研究期间共分离出33株IRE菌株。对其中20株进行分析，发现它们属于三种不同的脉冲型。所有这些分离株的细胞提取物均能水解亚胺培南。PCR和测序显示这些分离株携带KPC-2基因。在多变量分析中，高侵入性器械评分（P = 0.02）仍然是IRE分离的一个预测因素。IRE组的死亡率为33%，而对照组为9%。在多变量模型中控制混杂因素后，作为IRE病例与死亡率增加显著相关（比值比，8.3±8.6；95%置信区间，1.07至64；P = 0.043）。在特拉维夫，肠杆菌分离株中由于bla(KPC-2)导致的对亚胺培南耐药已在多个克隆中出现，与ISE对照组相比，尤其影响有多个侵入性器械的患者。IRE感染与死亡率增加相关。有必要加强措施控制IRE在医院内的传播。
