Liu Congcong, Wu Yuchen, Fang Yinfei, Sang Zi, Huang Ling, Dong Ning, Zeng Yu, Lu Jiayue, Zhang Rong, Chen Gongxiang
Department of Clinical Laboratory, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China.
Department of Clinical Laboratory, Dali Bai Autonomous Prefecture People's Hospital, Dali, China.
Front Microbiol. 2022 Mar 17;13:800993. doi: 10.3389/fmicb.2022.800993. eCollection 2022.
CG258 is the dominant carbapenemase-producing clone worldwide and treatment of infections caused by this clone relies largely on the last-line antibiotics, colistin, and tigecycline. However, the emergence and global dissemination of and - genes have significantly compromised their clinical applications. CG258 carrying both and - have not been reported. A colistin-resistant strain T698-1 belonging to ST1326, a member of CG258, was isolated from the intestinal sample of a patient and characterized by the antimicrobial susceptibility testing, conjugation assay, WGS and bioinformatics analysis. It was resistant to colistin, tetracycline, aminoglycoside, fluoroqinolone, phenicols, sulfonamide, and some β-lactams, and positive for , -, and ESBL genes ( and ). The - gene cluster was located in an multi-drug resistant (MDR) region flanked by Tn elements on an IncHI1B/FIB plasmid. The genetic context of - was slightly distinct from previously reported Tn-like structures, with an IS element disrupting the upstream Tn and its adjacent genetic elements. The gene was inserted into the backbone of an IncFII/FIA plasmid with the genetic context of IS---IS. To our knowledge, this is the first report of co-occurrence of and - in a CG258 strain. Though this strain is tigecycline sensitive, the acquisition of colistin and tigecycline resistance determinants by the endemic CG258 clone still poses a serious public health concern. CG258, which became resistant to multiple last resort antibiotics, would be the next emerging superbug.
CG258是全球范围内产生碳青霉烯酶的主要克隆株，由该克隆株引起的感染治疗在很大程度上依赖于最后一线抗生素——黏菌素和替加环素。然而，NDM和mcr基因的出现及全球传播严重影响了它们的临床应用。尚未有同时携带NDM和mcr基因的CG258的报道。从一名患者的肠道样本中分离出一株属于CG258成员ST1326的耐黏菌素菌株T698-1，并通过抗菌药物敏感性试验、接合试验、全基因组测序（WGS）和生物信息学分析对其进行了鉴定。它对黏菌素、四环素、氨基糖苷类、氟喹诺酮类、酚类、磺胺类以及一些β-内酰胺类药物耐药，NDM、mcr和超广谱β-内酰胺酶（ESBL）基因（blaCTX-M和blaTEM）呈阳性。mcr基因簇位于一个IncHI1B/FIB质粒上由转座子元件侧翼包围的多药耐药（MDR）区域。mcr的基因背景与先前报道的Tn样结构略有不同，一个插入序列元件破坏了上游转座子及其相邻的遗传元件。NDM基因插入到一个IncFII/FIA质粒的主干中，其基因背景为IS26-blaNDM-IS26。据我们所知，这是首次报道在CG258菌株中同时出现NDM和mcr基因。尽管该菌株对替加环素敏感，但地方性流行的CG258克隆株获得黏菌素和替加环素耐药决定簇仍然引起了严重的公共卫生关注。对多种最后手段抗生素耐药的CG258将成为下一个新出现的超级细菌。
