Department of Dental Hygiene, Silla University, Busan, Republic of Korea.
Department of Laboratory Medicine, MizMedi Hospital, Seoul, Republic of Korea.
Diagn Microbiol Infect Dis. 2014 Jul;79(3):373-7. doi: 10.1016/j.diagmicrobio.2014.03.007. Epub 2014 Mar 17.
This study was performed to investigate the prevalence and molecular epidemiology of Pseudomonas aeruginosa isolates from Korea that produce enzymes with extended-spectrum (ES) activity to β-lactams. A total of 205 non-duplicate P. aeruginosa clinical isolates were collected from 18 university hospitals in Korea. PCR and sequencing experiments were performed to identify genes encoding β-lactamases. PCR mapping and sequencing of the regions surrounding the β-lactamase genes were performed. Multilocus sequence typing experiments were performed. The most common sequence type (ST) was ST235 (n = 96), and 2 single-locus variants of ST235, ST1015 (n = 1) and ST1162 (n = 1), were also identified. These 3 STs were grouped as a clonal complex (CC), CC235. The remaining 107 isolates were identified as 59 different STs. Isolates belonging to CC235 showed higher rates of non-susceptibility to imipenem (85.4% versus 47.7%) and meropenem (92.7% versus 52.3%) compared to non-CC235 isolates. All the metallo-β-lactamase (MBL)-producing isolates were identified as CC235, except for 1 ST591. Genes encoding OXA-17 and OXA-142 were detected in 1 isolate and 4 isolates of CC235, respectively; while the bla(SHV-12) gene was detected in 4 non-CC235 isolates. Class A and D β-lactamases with ES activity play a role in acquiring ceftazidime resistance in P. aeruginosa in Korea. Production of IMP-6 and VIM-2 MBLs is the main mechanisms in acquiring resistance to ceftazidime and carbapenems in P. aeruginosa isolates in Korea. Clonal spread of P. aeruginosa CC235 may be an important conduit for the dissemination of MBL genes in Korea.
本研究旨在调查韩国产具有扩展谱（ES）活性的β-内酰胺酶的铜绿假单胞菌分离株的流行率和分子流行病学。从韩国的 18 家大学医院共收集了 205 例非重复铜绿假单胞菌临床分离株。进行了 PCR 和测序实验以鉴定编码β-内酰胺酶的基因。对β-内酰胺酶基因周围区域进行了 PCR 图谱和测序。进行了多位点序列分型实验。最常见的序列型（ST）为 ST235（n = 96），还鉴定出 2 种 ST235 的单一位点变异，ST1015（n = 1）和 ST1162（n = 1）。这 3 种 ST 被归为一个克隆群（CC），CC235。其余 107 株被鉴定为 59 种不同的 ST。属于 CC235 的分离株对亚胺培南（85.4%对 47.7%）和美罗培南（92.7%对 52.3%）的不敏感性率高于非 CC235 分离株。除 1 株 ST591 外，所有产金属β-内酰胺酶（MBL）的分离株均被鉴定为 CC235。在 1 株 CC235 分离株和 4 株 CC235 分离株中检测到编码 OXA-17 和 OXA-142 的基因，而在 4 株非 CC235 分离株中检测到 bla（SHV-12）基因。具有 ES 活性的 A 类和 D 类β-内酰胺酶在韩国铜绿假单胞菌获得头孢他啶耐药性中发挥作用。IMP-6 和 VIM-2 MBL 的产生是韩国铜绿假单胞菌分离株获得头孢他啶和碳青霉烯类耐药性的主要机制。铜绿假单胞菌 CC235 的克隆传播可能是韩国 MBL 基因传播的重要途径。
