Division of Infectious Diseases, Southern Illinois University School of Medicine, Springfield, IL, USA.
Division of Infectious Diseases, Southern Illinois University School of Medicine, Springfield, IL, USA.
Diagn Microbiol Infect Dis. 2020 May;97(1):114999. doi: 10.1016/j.diagmicrobio.2020.114999. Epub 2020 Jan 26.
We reviewed susceptibility of 840 A. baumannii complex isolates at two academic medical centers and explored their mechanism of carbapenem resistance. Carbapenem resistance rates among A. baumannii increased from <5% before 2005 to 55% in 2011 and declined thereafter. We subjected 86 isolates for further antibiotic susceptibility testing using E-test, screened for MBL and carbapenemase production, and performed PCR for bla genes. Statistical analyses included correlation of resistance genes with susceptibility. Sixty-one isolates were non-susceptible to carbapenems (MIC >2 μg/mL). Phenotypic screening showed carbapenemase production in 50 isolates, but none was positive for MBL. Among carbapenem non-susceptible isolates, the CHDL (group D carbapenemase) encoding genes bla (52%) and bla (28%) were the most frequent genes. In conclusion, carbapenem resistance rates in A. baumannii peaked in 2011 and have since declined in our region. Carbapenem resistance among A. baumannii was primarily associated with production of acquired CHDLs including OXA-23 and OXA-40.
我们回顾了两家学术医疗中心的 840 株鲍曼不动杆菌复合体分离株的易感性，并探讨了它们对碳青霉烯类药物耐药的机制。2005 年之前，鲍曼不动杆菌对碳青霉烯类药物的耐药率<5%，但在 2011 年增加到 55%，此后有所下降。我们对 86 株分离株进行了进一步的抗生素药敏试验，采用 E 试验进行检测，筛选 MBL 和碳青霉烯酶的产生情况，并进行 bla 基因的 PCR 检测。统计分析包括耐药基因与药敏之间的相关性。61 株对碳青霉烯类药物（MIC>2μg/ml）不敏感。表型筛选显示 50 株分离株产碳青霉烯酶，但无 MBL 阳性。在碳青霉烯类药物不敏感的分离株中，编码 blaCHDL（D 组碳青霉烯酶）的基因（52%）和 bla（28%）最为常见。总之，我们地区鲍曼不动杆菌的碳青霉烯类药物耐药率在 2011 年达到峰值，此后有所下降。鲍曼不动杆菌对碳青霉烯类药物的耐药主要与获得性 CHDLs（包括 OXA-23 和 OXA-40）的产生有关。
