Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Epidemiol Infect. 2012 Jan;140(1):137-45. doi: 10.1017/S0950268811000744. Epub 2011 Apr 18.
Carbapenem-resistant Acinetobacter baumannii (CRAB) are an increasing infectious threat in hospitals. We investigated the clinical epidemiology of CRAB infections vs. colonization in patients, and examined the mechanisms of resistance associated with elevated minimum inhibitory concentrations (MICs) for carbapenems. From January to June 2009, 75 CRAB strains were collected. CRAB infection was significantly associated with malignancy and a high APACHE II score. The most dominant resistance mechanism was ISAba1 preceding OXA-51, producing strains with overexpression of efflux pump. Strains carrying blaOXA-23-like enzymes had higher carbapenem MICs than those carrying blaOXA-51-like enzymes; however, the presence of multiple mechanisms did not result in increased resistance to carbapenems. There was no difference in the resistance mechanisms in strains from infected and colonized patients. The majority of strains were genetically diverse by DNA macrorestriction although there was evidence of clonal spread of four clusters of strains in patients.
鲍曼不动杆菌碳青霉烯耐药株（CRAB）是医院中日益严重的感染威胁。我们调查了患者中 CRAB 感染与定植的临床流行病学，并研究了与碳青霉烯最低抑菌浓度（MIC）升高相关的耐药机制。2009 年 1 月至 6 月，共收集了 75 株 CRAB 菌株。CRAB 感染与恶性肿瘤和高急性生理与慢性健康评分（APACHE II）显著相关。最主要的耐药机制是 ISAba1 位于 OXA-51 之前，导致外排泵过度表达。携带 blaOXA-23 样酶的菌株对碳青霉烯类的 MIC 值高于携带 blaOXA-51 样酶的菌株；然而，多种机制的存在并未导致对碳青霉烯类的耐药性增加。感染和定植患者的菌株耐药机制无差异。尽管有证据表明患者中有四个菌株簇的克隆传播，但大多数菌株的 DNA 宏限制图谱具有遗传多样性。
