Anderson Brian, Nicholas Sarah, Sprague Bruce, Campos Joseph, Short Billie, Singh Nalini
George Washington University School of Medicine, Center for Health Services and Community Research, Washington, DC 20010, USA.
Infect Control Hosp Epidemiol. 2008 Mar;29(3):250-5. doi: 10.1086/527513.
To investigate the epidemiology of multidrug-resistant Enterobacteriaceae (MDRE) in hospitalized infants.
From 2000 through 2005, active surveillance cultures for MDRE were performed for patients admitted to a 40-bed neonatal intensive care unit (NICU) that provides care for critically ill infants 6 months of age or younger. MDRE epidemiology and the genetic relatedness of MDRE strains determined by repetitive-sequence polymerase chain reaction were analyzed.
Active surveillance cultures revealed that 759 (23%) of 3,370 NICU infants (or approximately 1 in 5) developed MDRE colonization or infection and that 613 (72%) of the 853 isolates with epidemiologic data available were healthcare acquired. MDRE colonization occurred more frequently (in 653 infants [86%]) than did MDRE infection (in 106 [14%]). Of the 653 infants with MDRE colonization, 119 (18%) eventually became infected, with 29 (4%) acquiring sterile site infections. The most commonly isolated organisms were the Enterobacter species, accounting for 612 (71%) of the 862 isolates. Molecular epidemiologic analysis revealed that genetic-relatedness clustering (related clusters defined as having a genetic similarity coefficient greater than 95%) varied depending on microbial species. Clustering was detected for 36 (78%) of the 46 Enterobacter aerogenes isolates, 22 (45%) of the 49 Enterobacter cloacae isolates, and 13 (59%) of the 22 Klebsiella pneumoniae isolates.
Hospitalized infants are at significant risk of acquiring MDRE, specifically Enterobacter species, at the study institution. Active surveillance cultures identified colonized patients who likely contributed to the institutional reservoir of MDRE. Molecular epidemiologic studies suggest that both patient-to-patient transmission and de novo acquisition of resistance play a role in the acquisition of these organisms, and that the clinical significance of such acquisition varies by species. The high percentage of E. aerogenes isolates that demonstrated genetic clustering suggests that monitoring the prevalence of this organism could serve as a useful measure of compliance with infection control procedures.
调查住院婴儿中多重耐药肠杆菌科细菌（MDRE）的流行病学情况。
2000年至2005年期间，对一家拥有40张床位的新生儿重症监护病房（NICU）收治的患者进行了MDRE主动监测培养，该病房为6个月及以下的重症婴儿提供护理。分析了MDRE的流行病学情况以及通过重复序列聚合酶链反应确定的MDRE菌株的遗传相关性。
主动监测培养显示，3370名NICU婴儿中有759名（23%）（约五分之一）发生了MDRE定植或感染，在853株有流行病学数据的分离株中，有613株（72%）是医院获得性的。MDRE定植比MDRE感染更常见（653名婴儿[86%]），MDRE感染的有106名（14%）。在653名有MDRE定植的婴儿中，119名（18%）最终发生感染，其中29名（4%）发生了无菌部位感染。最常分离出的菌株是肠杆菌属，占862株分离株中的612株（71%）。分子流行病学分析显示，遗传相关性聚类（相关聚类定义为遗传相似系数大于95%）因微生物种类而异。在46株产气肠杆菌分离株中有36株（78%）检测到聚类，在49株阴沟肠杆菌分离株中有22株（45%）检测到聚类，在22株肺炎克雷伯菌分离株中有13株（59%）检测到聚类。
在该研究机构中，住院婴儿有获得MDRE的重大风险，尤其是肠杆菌属。主动监测培养确定了可能促成MDRE医院储存库的定植患者。分子流行病学研究表明，患者之间的传播和耐药性的从头获得在这些细菌的获得中都起作用，而且这种获得的临床意义因菌种而异。产气肠杆菌分离株中显示遗传聚类的比例很高，这表明监测该菌种的流行情况可作为衡量感染控制措施依从性的有用指标。
