Hu Longhua, Liu Yanling, Deng Linqiang, Zhong Qiaoshi, Hang Yaping, Wang Zengzeng, Zhan Lingling, Wang Liangxing, Yu Fangyou
Department of Clinical Laboratory, The Second Affiliated Hospital of Nanchang University, Nanchang China.
Department of Clinical Laboratory, Jiangxi Provincial People's Hospital, Nanchang China.
Front Microbiol. 2016 Aug 2;7:1190. doi: 10.3389/fmicb.2016.01190. eCollection 2016.
The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) often responsible for numerous hospital-associated outbreaks has become an important public health problem. From January 2013 to February 2014, a total of 41 non-duplicate K. pneumoniae isolates with carbapenem resistance, were collected at a tertiary teaching hospital in Nanchang, central China. Among 41 K. pneumoniae isolates, 28 were isolated from hospitalized patients including 19 from the patients in surgery intensive care unit (SICU) and 13 were isolated from ventilators. Twenty-four of 28 patients infected by CRKP have been submitted to mechanical ventilation using ventilator. More than 95% of the CRKP isolates were resistant to 13 antimicrobials tested. All CRKP isolates were confirmed as carbapenemase producer and were positive for bla KPC-2, with one positive for both blaKPC-2 and bla NDM-1. All carbapenemase-producing isolates harbored at least one of extended spectrum β-lactamase genes tested, among which 95.1% (39/41) of the tested isolates were found to harbor both bla CTX-M-24 and bla KPC-2, Of note, one isolate harbored simultaneously two carbapenemase genes (bla KPC-2 and bla NDM-1) and two ESBL genes (bla CTX-M-3 and bla TEM-104). To the best of our knowledge, coexistence of bla KPC-2 and bla CTX-M-24 in one isolate is first reported. MLST results showed that 41 CRKP isolates belonged to four sequence types (STs) including ST11, novel ST1854, novel ST1855, and ST1224. PFGE results displayed three PFGE clusters. Thirty-eight ST11 CRKP isolates (92.7%, 38/41) including all 13 isolates from ventilators and 25 isolates from patients from seven wards (18 from SICU) belonged to same PFGE cluster, indicating these isolates were clonally related. Fifteen isolates have an identical undistinguished pattern (100% similarity) forming a single clonal population. Moreover, this clone was exclusively linked to the cases attended in SICU and linked to the Ventilators. Additionally, the other SICU cases were linked to closely related clones (similarity greater than 95%). These data indicated that the occurrence of a clonal outbreak associated with ventilators has been found. In conclusion, outbreak by ventilator-associated ST11 K. pneumoniae with co-production of CTX-M-24 and KPC-2 is found in a SICU of a tertiary teaching hospital in central China.
耐碳青霉烯类肺炎克雷伯菌（CRKP）的出现常常导致众多医院内感染暴发，已成为一个重要的公共卫生问题。2013年1月至2014年2月，在中国中部南昌的一家三级教学医院共收集了41株非重复的耐碳青霉烯类肺炎克雷伯菌分离株。在这41株肺炎克雷伯菌分离株中，28株从住院患者中分离得到，其中19株来自外科重症监护病房（SICU）的患者，13株从呼吸机上分离得到。28例感染CRKP的患者中有24例已使用呼吸机进行机械通气。超过95%的CRKP分离株对13种测试抗菌药物耐药。所有CRKP分离株均被确认为碳青霉烯酶产生菌，bla KPC-2呈阳性，其中1株blaKPC-2和bla NDM-1均为阳性。所有产碳青霉烯酶的分离株均携带至少一种测试的超广谱β-内酰胺酶基因，其中95.1%（39/41）的测试分离株同时携带bla CTX-M-24和bla KPC-2。值得注意的是，1株分离株同时携带两种碳青霉烯酶基因（bla KPC-2和bla NDM-1）和两种超广谱β-内酰胺酶基因（bla CTX-M-3和bla TEM-104）。据我们所知，首次报道了1株分离株中bla KPC-2和bla CTX-M-24共存的情况。多位点序列分型（MLST）结果显示，41株CRKP分离株属于4种序列类型（STs），包括ST11、新的ST1854、新的ST1855和ST1224。脉冲场凝胶电泳（PFGE）结果显示有3个PFGE簇。38株ST11 CRKP分离株（92.7%，38/41），包括所有13株从呼吸机上分离得到的菌株以及来自7个病房患者的25株菌株（18株来自SICU）属于同一PFGE簇，表明这些分离株具有克隆相关性。15株分离株具有相同的难以区分的图谱（100%相似性），形成一个单一的克隆群体。此外，该克隆仅与SICU的病例相关，并与呼吸机相关。另外，其他SICU病例与密切相关的克隆相关（相似性大于95%）。这些数据表明已发现与呼吸机相关的克隆暴发。总之，在中国中部一家三级教学医院的SICU中发现了由呼吸机相关的ST11肺炎克雷伯菌同时产生CTX-M-24和KPC-2引起的暴发。
