Graduate School in Pharmaceutical Science, Osaka University, Japan.
Second Affiliated Hospital of Zhejiang University, 88 Jiefang Rd, Hangzhou 310009, PR China.
J Med Microbiol. 2011 Dec;60(Pt 12):1813-1819. doi: 10.1099/jmm.0.025668-0. Epub 2011 Aug 11.
Carbapenem resistance in members of the Enterobacteriaceae is increasing. To evaluate the effects of tigecycline and polymyxin B against carbapenem-non-susceptible pathogens, 89 representative clinical carbapenem-non-susceptible Enterobacteriaceae isolates were recovered from seven hospitals from four cities in China during 2006-2009: 30 Serratia marcescens, 35 Klebsiella pneumoniae, seven Enterobacter cloacae, six Enterobacter aerogenes, five Escherichia coli, four Citrobacter freundii and two Klebsiella oxytoca isolates. Twenty-eight S. marcescens isolates were indistinguishable. The 35 K. pneumoniae isolates belonged to 12 clonal strains. Among the 89 Enterobacteriaceae isolates, 82 produced KPC-2, seven produced IMP (three produced KPC-2 simultaneously), three did not produce any carbapenemases and nine were deficient in porins. Polymyxin B was much more active than tigecycline against carbapenem-non-susceptible Enterobacteriaceae. The MIC(50) and MIC(90) of imipenem, meropenem, ertapenem, polymyxin B and tigecycline were 8 and 32 µg ml(-1), 8 and 32 µg ml(-1), 16 and 128 µg ml(-1), 0.5 and 16 µg ml(-1), and 4 and 16 µg ml(-1), respectively. Rates of susceptibility to imipenem, meropenem, ertapenem and polymyxin B were 30.0%, 27.5%, 2.5% and 89.2% by CLSI criteria. The rate of susceptibility to tigecycline was 40% and 17.5% by Food and Drug Administration (MIC ≤2 µg ml(-1)) and European Committee on Antimicrobial Susceptibility Testing (MIC ≤1 µg ml(-1)) criteria, respectively. KPC-2- or IMP-producing E. coli transconjugants exhibited reduced susceptibility to carbapenems but were susceptible to polymyxin B and tigecycline with an MIC range of 0.5-2 µg ml(-1), 0.25-2 µg ml(-1), 0.5-4 µg ml(-1), 0.5 µg ml(-1) and 0.5-1 µg ml(-1). In conclusion, carbapenem resistance in Enterobacteriaceae is mainly due to production of KPC-2, and polymyxin B is active for the carbapenem-resistant Enterobacteriaceae.
肠杆菌科的碳青霉烯类耐药性正在增加。为了评估替加环素和多黏菌素 B 对碳青霉烯类不敏感病原体的作用，从中国四个城市的七家医院收集了 89 株具有代表性的临床碳青霉烯类不敏感肠杆菌科分离株，包括 30 株粘质沙雷氏菌、35 株肺炎克雷伯菌、7 株阴沟肠杆菌、6 株产气肠杆菌、5 株大肠埃希菌、4 株弗氏柠檬酸杆菌和 2 株产酸克雷伯菌。28 株粘质沙雷氏菌分离株无法区分。35 株肺炎克雷伯菌分离株属于 12 个克隆株。在 89 株肠杆菌科分离株中，82 株产生 KPC-2，7 株产生 IMP（3 株同时产生 KPC-2），3 株不产生任何碳青霉烯酶，9 株缺乏孔蛋白。多黏菌素 B 对碳青霉烯类不敏感的肠杆菌科具有比替加环素更高的活性。亚胺培南、美罗培南、厄他培南、多黏菌素 B 和替加环素的 MIC（50）和 MIC（90）分别为 8 和 32μg/ml、8 和 32μg/ml、16 和 128μg/ml、0.5 和 16μg/ml、4 和 16μg/ml。按 CLSI 标准，亚胺培南、美罗培南、厄他培南和多黏菌素 B 的敏感性率分别为 30.0%、27.5%、2.5%和 89.2%。按美国食品和药物管理局（MIC≤2μg/ml）和欧洲抗菌药物敏感性试验委员会（MIC≤1μg/ml）标准，替加环素的敏感性率分别为 40%和 17.5%。产 KPC-2 或 IMP 的大肠埃希菌转座子对碳青霉烯类的敏感性降低，但对多黏菌素 B 和替加环素敏感，MIC 范围分别为 0.5-2μg/ml、0.25-2μg/ml、0.5-4μg/ml、0.5μg/ml 和 0.5-1μg/ml。总之，肠杆菌科的碳青霉烯类耐药性主要是由于 KPC-2 的产生，多黏菌素 B 对碳青霉烯类耐药的肠杆菌科具有活性。
