Ma Xiaolong, Lv Xiaodong, Feng Sihan, Liu Ruishan, Fu Hao, Gao Feng, Xu Hao
Department of Respiratory Medicine, the First Hospital of Jiaxing (Affiliated Hospital of Jiaxing University), Jiaxing, People's Republic of China.
Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
Infect Drug Resist. 2022 Apr 29;15:2293-2299. doi: 10.2147/IDR.S360715. eCollection 2022.
To investigate the phenotypic and genomic characteristics of the multi-drug resistant and hypervirulent strain recovered from bacteremia.
Antimicrobial susceptibility testing (AST) was performed by the microdilution method. Antimicrobial resistance genes, virulence-associated genes, multilocus sequence typing (MLST), and plasmid replicon were characterized by next-generation sequencing (NGS) and nanopore sequencing. S1 nuclease-pulsed field gel electrophoresis (S1-PFGE) and Southern blotting were performed to characterize the plasmid profile.
The hypervirulent colistin- and carbapenem-resistant strain DY2009 was identified as ST5571, co-carrying , and . In silico analysis found that it was K2 serotype. AST results revealed that DY2009 was resistant to carbapenems, cephalosporins, ciprofloxacin, chloramphenicol, and colistin but remained susceptible to aztreonam, gentamicin, amikacin, and tigecycline. Through the whole-genome analysis, a variety of virulence determinants were identified, including . Plasmid analysis confirmed that the and gene harbored a ~33 kb IncX4 plasmid and a ~44 kb IncX3 plasmid. In contrast, was encoded by chromosome.
To the best of our knowledge, we first report the clinical hypervirulent isolate co-producing MCR-1, NDM-1, and OXA-10 causing bacteremia. We found that and genes were located on two self-conjugative epidemic plasmids, contributing to the widespread MCR-1 and NDM-1 in China. The results of this work improve our understanding of the genetic background of colistin- and carbapenem-resistant isolate from bacteremia and the resistance mechanisms. Our findings highlight the urgent need for infection control of such strain to prevent it from becoming an extensive-drug resistant clone.
研究从菌血症中分离出的多重耐药和高毒力菌株的表型及基因组特征。
采用微量稀释法进行药敏试验。通过二代测序（NGS）和纳米孔测序对耐药基因、毒力相关基因、多位点序列分型（MLST）和质粒复制子进行特征分析。采用S1核酸酶脉冲场凝胶电泳（S1-PFGE）和Southern印迹法对质粒图谱进行特征分析。
高毒力耐黏菌素和碳青霉烯类菌株DY2009被鉴定为ST5571，同时携带 、 和 。电子分析发现其为K2血清型。药敏试验结果显示，DY2009对碳青霉烯类、头孢菌素类、环丙沙星、氯霉素和黏菌素耐药，但对氨曲南、庆大霉素、阿米卡星和替加环素敏感。通过全基因组分析，鉴定出多种毒力决定因素，包括 。质粒分析证实， 和 基因分别携带一个约33 kb的IncX4质粒和一个约44 kb的IncX3质粒。相比之下， 由染色体编码。
据我们所知，我们首次报道了临床分离出的同时产生MCR-1、NDM-1和OXA-10并导致菌血症的高毒力菌株。我们发现 和 基因位于两个自我接合的流行质粒上，这导致了MCR-1和NDM-1在中国的广泛传播。这项工作的结果增进了我们对菌血症中耐黏菌素和碳青霉烯类分离株的遗传背景及耐药机制的理解。我们的研究结果凸显了对此类菌株进行感染控制以防止其成为广泛耐药克隆的迫切需求。
