Kim Soo-Young, Park Yeon-Joon, Yu Jin-Kyung, Kim Han Sik, Park Yong Sung, Yoon Jong-Bok, Yoo Jin-Young, Lee Kyungwon
Department of Clinical Pathology, College of Medicine, The Catholic University of Korea, St. Vincent's Hospital, Suwon 442-723, South Korea.
Diagn Microbiol Infect Dis. 2007 Jan;57(1):85-91. doi: 10.1016/j.diagmicrobio.2006.05.008. Epub 2006 Jul 18.
In this study, we examined the prevalence of and mechanisms of decreased susceptibility to either imipenem or meropenem in Klebsiella pneumoniae isolates. A total of 230 clinical isolates of K. pneumoniae were collected from 13 clinical laboratories from a nationwide distribution. The MICs of imipenem and meropenem were determined by the agar dilution method. To characterize the isolates with decreased susceptibility to carbapenems (MICs of >2 microg/mL), we performed polymerase chain reaction amplification of a variety of beta-lactamase genes, isoelectric focusing, and outer membrane profile analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry. Three isolates (BD6, BD8, and KN16) exhibited decreased susceptibility to carbapenems with imipenem MICs of 1, 4, and 8 microg/mL and meropenem MICs of 4, 8, and 4, respectively. Isolate BD6 produced bla(TEM-1), bla(SHV-12), and bla(OXA-17); isolate BD8 produced bla(GES-3), bla(SHV-12), and bla(OXA-17); and isolate KN16 produced bla(TEM-11), bla(SHV-12), and bla(DHA-1). In all the 3 isolates, OmpK35 porin was not expressed, and in 1 isolate (KN16), OmpK36 was not expressed either. The prevalence of decreased susceptibility to carbapenems was low (1.3%), and none of them showed overt resistance to carbapenems. Decreased susceptibility to carbapenems can occur in K. pneumoniae when bla(GES-3), bla(TEM-11), bla(SHV-12), bla(OXA-17), and/or bla(DHA-1) are produced in combination with porin loss. In addition, to our knowledge, this is the 1st report of bla(OXA-17) in Enterobacteriaceae.
在本研究中，我们检测了肺炎克雷伯菌分离株对亚胺培南或美罗培南敏感性降低的发生率及机制。从全国分布的13个临床实验室收集了总共230株肺炎克雷伯菌临床分离株。采用琼脂稀释法测定亚胺培南和美罗培南的最低抑菌浓度（MIC）。为了鉴定对碳青霉烯类药物敏感性降低（MIC>2μg/mL）的分离株，我们进行了多种β-内酰胺酶基因的聚合酶链反应扩增、等电聚焦以及使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和质谱进行外膜图谱分析。三株分离株（BD6、BD8和KN16）对碳青霉烯类药物的敏感性降低，亚胺培南的MIC分别为1、4和8μg/mL，美罗培南的MIC分别为4、8和4μg/mL。分离株BD6产生bla(TEM-1)、bla(SHV-12)和bla(OXA-17)；分离株BD8产生bla(GES-3)、bla(SHV-12)和bla(OXA-17)；分离株KN16产生bla(TEM-11)、bla(SHV-12)和bla(DHA-1)。在所有这三株分离株中，OmpK35孔蛋白均未表达，并且在一株分离株（KN16）中，OmpK36也未表达。对碳青霉烯类药物敏感性降低的发生率较低（1.3%），并且它们均未表现出对碳青霉烯类药物的明显耐药性。当同时产生bla(GES-3)、bla(TEM-11)、bla(SHV-12)、bla(OXA-17)和/或bla(DHA-1)并伴有孔蛋白缺失时，肺炎克雷伯菌可能会出现对碳青霉烯类药物敏感性降低的情况。此外，据我们所知，这是肠杆菌科中bla(OXA-17)的首次报道。
