Zheng Rui, Zhang Qian, Guo Yidan, Feng Yue, Liu Li, Zhang Amei, Zhao Yue, Yang Xiaoyu, Xia Xueshan
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, China.
Faculty of Life Science and Technology, Kunming University of Science and Technology, No. 727 Jing Ming Road, Chenggong District, Kunming, Yunnan, China.
Ann Clin Microbiol Antimicrob. 2016 Feb 19;15:10. doi: 10.1186/s12941-016-0124-6.
In the past decade, the carbapenemase-producing Enterobacteriaceae (CPE) have been reported worldwide. Emergence of carbapenemase-producing strains among Enterobacteriaceae has been a challenge for treatment of clinical infection. The present study was undertaken to investigate the characteristics of carbapenem-resistant Klebsiella pneumoniae recovered from an outbreak that affected 17 neonatal patients in neonatal intensive care unit (NICU) of Kunming City Maternal and Child health Hospital, which is located in the Kunming city in far southwest of China.
Minimum inhibitory concentrations (MICs) for antimicrobial agents were determined according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI); Modified Hodge test and Carba-NP test were preformed to identified the phenotypes of carbapenemases producing; To determine whether carbapenem resistance was transferable, a conjugation experiment was carried out in mixed broth cultures; Resistant genes were detected by using PCR and sequencing; Plasmids were typed by PCR-based replicon typing method; Clone relationships were analyzed by using multilocus-sequence typing (MLST) and pulsed field gel electrophoresis (PFGE).
Eighteen highly carbapenem-resistant Klebsiella pneumoniae were isolated from patients in NICU and one carbapenem-resistant K. pneumoniae isolate was detected in incubator water. All these isolates harbored bla NDM-1. Moreover, other resistance genes, viz., bla IMP-4 , bla SHV-1 , bla TEM-1 , bla CTX-M-15 , qnrS1, qnrB4, and aacA4 were detected. The bla NDM-1 gene was located on a ca. 50 kb IncFI type plasmid. PFGE analysis showed that NDM-1-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 105.
NDM-1 producing strains present in the hospital environment pose a potential risk and the incubator water may act as a diffusion reservoir of NDM-1- producing bacteria. Nosocomial surveillance system should play a more important role in the infection control to limit the spread of these pathogens.
在过去十年中，产碳青霉烯酶肠杆菌科细菌（CPE）已在全球范围内被报道。肠杆菌科中产碳青霉烯酶菌株的出现对临床感染的治疗构成了挑战。本研究旨在调查从昆明市妇幼保健院新生儿重症监护病房（NICU）的一次疫情中分离出的耐碳青霉烯肺炎克雷伯菌的特征，该医院位于中国西南部偏远的昆明市。
根据临床和实验室标准协会（CLSI）的指南测定抗菌药物的最低抑菌浓度（MIC）；进行改良 Hodge 试验和 Carba-NP 试验以鉴定产碳青霉烯酶的表型；为确定碳青霉烯耐药性是否可转移，在混合肉汤培养物中进行接合试验；使用 PCR 和测序检测耐药基因；通过基于 PCR 的复制子分型方法对质粒进行分型；使用多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）分析克隆关系。
从 NICU 的患者中分离出 18 株高度耐碳青霉烯的肺炎克雷伯菌，在培养箱水中检测到 1 株耐碳青霉烯肺炎克雷伯菌分离株。所有这些分离株都携带 blaNDM-1。此外，还检测到其他耐药基因，即 blaIMP-4、blaSHV-1、blaTEM-1、blaCTX-M-15、qnrS1、qnrB4 和 aacA4。blaNDM-1 基因位于约 50 kb 的 IncFI 型质粒上。PFGE 分析表明，产 NDM-1 的肺炎克雷伯菌具有克隆相关性，MLST 将它们归为序列型 105。
医院环境中存在的产 NDM-1 菌株构成潜在风险，培养箱水可能作为产 NDM-1 细菌的扩散储存库。医院感染监测系统应在感染控制中发挥更重要的作用，以限制这些病原体的传播。
