AMR Research Center, National Institute of Infectious Diseases, Tokyo, Japan.
Department of Molecular Life Science, Tokai University School of Medicine, Kanagawa, Japan.
PLoS One. 2021 Jul 28;16(7):e0231119. doi: 10.1371/journal.pone.0231119. eCollection 2021.
Carbapenem-resistant Enterobacterales (CRE) represent a serious threat to public health due to the lack of treatment and high mortality. The rate of antimicrobial resistance of Enterobacterales isolates to major antimicrobials, including carbapenems, is much higher in Vietnam than in Western countries, but the reasons remain unknown due to the lack of genomic epidemiology research. A previous study suggested that carbapenem resistance genes, such as the carbapenemase gene blaNDM, spread via plasmids among Enterobacterales in Vietnam. In this study, we characterized blaNDM-carrying plasmids in Enterobacterales isolated in Vietnam, and identified several possible cases of horizontal transfer of plasmids both within and among species of bacteria. Twenty-five carbapenem-nonsusceptible isolates from a medical institution in Hanoi were sequenced on Illumina short-read sequencers, and 13 blaNDM-positive isolates, including isolates of Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Morganella morganii, and Proteus mirabilis, were further sequenced on an Oxford Nanopore Technologies long-read sequencer to obtain complete plasmid sequences. Almost identical 73 kb IncFII(pSE11)::IncN hybrid plasmids carrying blaNDM-1 were found in a P. mirabilis isolate and an M. morganii isolate. A 112 kb IncFII(pRSB107)::IncN hybrid plasmid carrying blaNDM-1 in an E. coli isolate had partially identical sequences with a 39 kb IncR plasmid carrying blaNDM-1 and an 88 kb IncFII(pHN7A8)::IncN hybrid plasmid in a C. freundii isolate. 148-149 kb IncFIA(Hl1)::IncA/C2 plasmids and 75-76 kb IncFII(Yp) plasmids, both carrying blaNDM-1 were shared among three sequence type 11 (ST11) isolates and three ST395 isolates of K. pneumoniae, respectively. Most of the plasmids co-carried genes conferring resistance to clinically relevant antimicrobials, including third-generation cephalosporins, aminoglycosides, and fluoroquinolones, in addition to blaNDM-1. These results provide insight into the genetic basis of CRE in Vietnam, and could help control nosocomial infections.
耐碳青霉烯肠杆菌科 (CRE) 由于缺乏治疗方法和高死亡率，对公共健康构成严重威胁。越南肠杆菌科分离株对抗生素的抗药性，包括碳青霉烯类，比西方国家高得多，但由于缺乏基因组流行病学研究，其原因尚不清楚。先前的研究表明，耐碳青霉烯类基因，如 blaNDM 碳青霉烯酶基因，通过质粒在越南肠杆菌科之间传播。在本研究中，我们对越南分离的耐碳青霉烯肠杆菌科中的 blaNDM 携带质粒进行了特征描述，并鉴定了几种可能的质粒在细菌种内和种间水平转移的情况。对河内一家医疗机构的 25 株耐碳青霉烯类非敏感分离株进行了 Illumina 短读测序，对 13 株 blaNDM 阳性分离株，包括肺炎克雷伯菌、大肠埃希菌、弗氏柠檬酸杆菌、摩根摩根菌和奇异变形杆菌，进行了 Oxford Nanopore Technologies 长读测序，以获得完整的质粒序列。在奇异变形杆菌分离株和摩根摩根菌分离株中发现了几乎相同的 73 kb IncFII(pSE11)::IncN 杂交质粒，携带 blaNDM-1。在一株大肠埃希菌分离株中发现的携带 blaNDM-1 的 112 kb IncFII(pRSB107)::IncN 杂交质粒与携带 blaNDM-1 的 39 kb IncR 质粒和弗氏柠檬酸杆菌分离株中的 88 kb IncFII(pHN7A8)::IncN 杂交质粒具有部分相同的序列。在 3 株 ST11 分离株和 3 株 ST395 肺炎克雷伯菌分离株中，分别发现了 148-149 kb IncFIA(Hl1)::IncA/C2 质粒和 75-76 kb IncFII(Yp) 质粒，均携带 blaNDM-1。大多数质粒共同携带了对临床相关抗生素的耐药基因，包括第三代头孢菌素、氨基糖苷类和氟喹诺酮类，以及 blaNDM-1。这些结果为越南 CRE 的遗传基础提供了深入的了解，并有助于控制医院感染。
