// Jiao Feng 1, * , Zhe Yin 1, * , Zhe Zhan 1 , Haifeng Mao 2 , Xiaoyuan Jiang 1 , Lijun Zeng 1 , Wenhui Yang 1 , Huiying Yang 1 , Jinglin Wang 1 , Haijian Zhou 3, 4 and Dongsheng Zhou 1 1 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China 2 The First People’s Hospital of Lianyungang, Lianyungang, 222002, China 3 State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China 4 Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310003, China * These authors contributed equally to this work Correspondence to: Dongsheng Zhou, email: dongshengzhou1977@gmail.com Haijian Zhou, email: zhouhaijian@icdc.cn Jinglin Wang, email: wjlwjl0801@sina.com Keywords: Klebsiella pneumoniae; multidrug resistance; plasmids; p675920-1 Received: July 10, 2017 Accepted: December 05, 2017 Published: January 13, 2018 ABSTRACT This study dealt with detailed genomic characterization of two multidrug resistant (MDR) plasmids p675920-1 and p675920-2 from a single clinical Klebsiella pneumoniae isolate 675920. p675920-1 was essentially a hybrid of the IncFII plasmid pHN7A8 and the IncR plasmid pKPC-LK30, and functioned as an IncFII plasmid with inactivation of the IncR replication gene. The backbone of p675920-2 was a hybrid of a novel replicon, three maintenance regions (22.0-, 2.7-, 2.6-kb in length, respectively) as found in pKPYL2, p10164-3 and pK1HV, respectively, and the entire 25.9-kb conjugal transfer region of pKPYL2. p675920-1 and p675920-2 carried a large number of resistance genes, which contributed to resistance to at least seven classes of antibiotics (β-lactams, quinolones, aminoglycosides, fosfomycins, sulphonamides, trimethoprims, and tetracyclines) and one kind of heavy mental (mercury). All of these resistance genes are associated with mobile elements such as insertion sequences, insertion sequence-based transposition units, and transposons, which constituted a total of three novel MDR regions, two in p675920-1 and another in p675920-2. Coexistence of two MDR plasmids p675920-1 and p675920-2 made K. pneumoniae 675920 tend to become extensively drug-resistant.