Hyle Emily P, Lipworth Adam D, Zaoutis Theoklis E, Nachamkin Irving, Fishman Neil O, Bilker Warren B, Mao Xiangquin, Lautenbach Ebbing
Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6021, USA.
Clin Infect Dis. 2005 May 1;40(9):1317-24. doi: 10.1086/429239. Epub 2005 Mar 30.
The importance of infections due to extended-spectrum beta -lactamase-producing Escherichia coli and Klebsiella species (ESBL-EK) has been increasingly recognized in recent years. ESBL-EK infections are of clinical concern, because few antimicrobials are available as therapeutic options. Increased reliance on carbapenems has led to increasing carbapenem resistance. Efforts to maintain current therapeutic options for ESBL-EK infections are essential.
We conducted a case-control study to identify risk factors for multidrug resistance (MDR) among ESBL-EK. All patients at our institution who had an inpatient clinical culture result positive for an ESBL-EK during the period of 1 June 1997 through 31 December 2002 were eligible for inclusion. An MDR ESBL-EK was defined as ESBL-EK demonstrating resistance to trimethoprim-sulfamethoxazole, aminoglycosides, and quinolones. All available ESBL-EK isolates were characterized by pulsed-field gel electrophoresis (PFGE).
Of 361 total ESBL-EK isolates, 68 (18.8%) were MDR. During the study period, the prevalence of MDR among ESBL-EK isolates increased from 12.5% to 26.9%. The only independent risk factor for MDR ESBL-EK was the infecting organism (i.e., Klebsiella pneumoniae; adjusted odds ratio, 11.7; 95% confidence interval, 4.77-28.51; P < .001). Prior antibiotic use was not independently associated with MDR ESBL-EK. PFGE patterns from K. pneumoniae isolates indicated close genetic relatedness among a substantial proportion of isolates.
The emergence of MDR among ESBL-EK has important implications for the future ability to treat these infections. The strong association between the species of infecting organism and MDR suggests that the epidemiology in K. pneumoniae may be unique. PFGE results suggest that horizontal spread is important in the emergence of MDR ESBL-EK.
近年来，产超广谱β-内酰胺酶的大肠埃希菌和克雷伯菌属（ESBL-EK）引起的感染的重要性日益受到认可。ESBL-EK感染引起临床关注，因为作为治疗选择的抗菌药物很少。对碳青霉烯类药物的依赖增加导致碳青霉烯类耐药性上升。维持当前ESBL-EK感染治疗选择的努力至关重要。
我们进行了一项病例对照研究，以确定ESBL-EK中多重耐药（MDR）的危险因素。1997年6月1日至2002年12月31日期间在我们机构住院临床培养结果为ESBL-EK阳性的所有患者均符合纳入标准。MDR ESBL-EK定义为对甲氧苄啶-磺胺甲恶唑、氨基糖苷类和喹诺酮类耐药的ESBL-EK。所有可用的ESBL-EK分离株均通过脉冲场凝胶电泳（PFGE）进行特征分析。
在361株ESBL-EK分离株中，68株（18.8%）为MDR。在研究期间，ESBL-EK分离株中MDR的患病率从12.5%增至26.9%。MDR ESBL-EK的唯一独立危险因素是感染菌（即肺炎克雷伯菌；校正比值比，11.7；95%置信区间，4.77 - 28.51；P <.001）。既往抗生素使用与MDR ESBL-EK无独立关联。肺炎克雷伯菌分离株的PFGE图谱表明相当一部分分离株之间存在密切的遗传相关性。
ESBL-EK中MDR的出现对未来治疗这些感染的能力具有重要意义。感染菌种类与MDR之间的强关联表明肺炎克雷伯菌的流行病学可能具有独特性。PFGE结果表明水平传播在MDR ESBL-EK的出现中很重要。
