Division of Infectious Diseases, Medical College, Hanyang University, Seoul, South Korea.
Chemotherapy. 2010;56(1):46-53. doi: 10.1159/000290972. Epub 2010 Mar 4.
Quinolone resistance is frequently associated with extended-spectrum cephalosporin resistance in Enterobacteriaceae.
The characteristics of plasmid-mediated quinolone resistance (PMQR) genes [qnr genes, aac(6')-Ib-cr and qepA] in clinical isolates of Klebsiella pneumoniae and Escherichia coli resistant to extended-spectrum cephalosporin were studied.
5 and 4 of 95 E. coli isolates but 46 (86/187) and 6% (12/187) of K. pneumoniae had qnr and aac(6')-Ib-cr, respectively, and 8 K. pneumoniae contained both genes.qepA was not identified. qnrB, especially qnrB4, was the predominant qnr subtype in K. pneumoniae [94 (88 qnrB of 94 qnr) and 88% (77 qnrB4 of 88 qnrB), respectively], and presence of qnrB4 was closely related with DHA-1 beta-lactamase (99%). However, K. pneumoniae isolates with qnrB4 and bla(DHA-1) were clonally diverse. beta-Lactamases produced by PMQR-containing isolates were variable: CMY-1, CTX-M-14, CTX-M-15, DHA-1, OXA type, SHV-2a, and SHV-12.
PMQR genes are widely distributed among clinical isolates of K. pneumoniae, and qnrB4 associated with bla(DHA-1) was the most common PMQR gene in Korea.
肠杆菌科中的喹诺酮耐药通常与超广谱头孢菌素耐药相关。
研究了对超广谱头孢菌素耐药的肺炎克雷伯菌和大肠埃希菌临床分离株中质粒介导的喹诺酮耐药（PMQR）基因[qnr 基因、aac(6')-Ib-cr 和 qepA]的特征。
95 株大肠埃希菌分离株中有 5 株和 4 株分别携带 qnr 和 aac(6')-Ib-cr，而 187 株肺炎克雷伯菌中有 46 株和 6%分别携带 qnr 和 aac(6')-Ib-cr，8 株肺炎克雷伯菌同时携带这两种基因。未鉴定出 qepA。qnrB，特别是 qnrB4，是肺炎克雷伯菌中主要的 qnr 亚型[94 株（94 株 qnr 中的 88 株 qnrB）和 88%（88 株 qnrB 中的 77 株 qnrB4）]，qnrB4 的存在与 DHA-1 型β-内酰胺酶密切相关（99%）。然而，携带 qnrB4 和 bla(DHA-1)的肺炎克雷伯菌分离株具有克隆多样性。携带 PMQR 基因的分离株产生的β-内酰胺酶各不相同：CMY-1、CTX-M-14、CTX-M-15、DHA-1、OXA 型、SHV-2a 和 SHV-12。
PMQR 基因在韩国肺炎克雷伯菌的临床分离株中广泛分布，qnrB4 与 bla(DHA-1)相关，是最常见的 PMQR 基因。
