Emergence of an ST1326 (CG258) Multi-Drug Resistant Klebsiella pneumoniae Co-harboring mcr-8.2 , ESBL Genes, and the Resistance-Nodulation-Division Efflux Pump Gene Cluster tmexCD1-toprJ1 in China

• Published in: Frontiers in microbiology 2022-03, Vol.13, p.800993-800993
• Main Authors: Liu, Congcong, Wu, Yuchen, Fang, Yinfei, Sang, Zi, Huang, Ling, Dong, Ning, Zeng, Yu, Lu, Jiayue, Zhang, Rong, Chen, Gongxiang
• Format: Article
• Language: English
• Subjects: CG258; ESBL genes; Klebsiella pneumoniae; mcr-8.2; Microbiology; tmexCD1-toprJ1
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.800993

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.