Coexistence of blaNDM-1 and rmtC on a Transferrable Plasmid of a Novel ST192 Klebsiella aerogenes Clinical Isolate

Abstract

Xiaofei Shen,1 Li Liu,2 Jingyi Yu,2 Xingwei Cao,3 Qing Zhan,4 Yinjuan Guo,5,6 Liangxing Wang,1 Fangyou Yu5,6 1Department of Respiratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of China; 2Department of Laboratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of China; 3Jiangxi Provincial Key Laboratory of Medicine, Clinical Laboratory of the Second Affiliated Hospital of Nanchang University, Nanchang 330006, People’s Republic of China; 4Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, People’s Republic of China; 5Department of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People’s Republic of China; 6Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People’s Republic of ChinaCorrespondence: Liangxing WangDepartment of Respiratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of ChinaEmail [email protected] YuDepartment of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People’s Republic of ChinaEmail [email protected]: The occurrence and development of antibiotic resistance are mainly caused by the spread of large plasmids carrying multiple antibiotic resistance genes. Recently, the association between 16S rRNA methyltransferase genes and β-lactamase genes carried by the same plasmid is of concern.Methods: The Klebsiella aerogenes 1564 was isolated from the catheter tip of a patient in a tertiary hospital, Shanghai, China. The presence of the blaNDM-1 and rmtC genes were assessed by PCR. Complete sequence of plasmid p1564 was determined. The K. aerogenes 1564 was characterized by antimicrobial susceptibility testing, Carbapenemase phenotype confirmation testing, conjugation experiment, S1-PFGE and multilocus sequence typing (MLST).Results: Herein, we found that a New Delhi Metallo-β-lactamase-1 gene (blaNDM-1) and a 16S rRNA methyltransferase gene (rmtC) coexisted on a transferrable plasmid of a carbapenem-resistant K. aerogenes clinical isolate. The K. aerogenes clinical isolate was found to belong to a novel sequence type 192 (ST192) determined by MLST. The sequencing results of the plasmid p1564 carrying blaNDM-1 gene and rmtC gene showed that the size and guanine-cytosine content of the plasmid were 136, 902 bp and 51.8%, with 164 putative ORFs and two multidrug resistance gene islands. In addition to blaNDM-1and rmtC, the plasmid contained bleomycin resistance gene (bleMBL), CMY-6β-lactamase gene (blaCMY-6), quaternary ammonium compound resistance gene (sugE), truncated quaternary ammonium compound resistance gene (qacEΔ1), aminoglycoside resistance gene (aacA4) and sulfonamide resistance gene (sul1). By comparison, p1564 has high homology with pHS36-NDM from Salmonella enterica subsp. enterica serovar Stanley reported in China, with similar size and both belonging to plasmid incompatibility group A/C.Conclusion: The present study demonstrated for the first time the co-existence of rmtC and blaNDM-1 in a novel ST192 K. aerogenes. The spread of plasmids harboring both blaNDM-1 and rmtC may occur among Enterobacteriaceae in China.Keywords: Klebsiella aerogenes, plasmid, blaNDM-1, rmtC

Keywords

• klebsiella aerogenes
• plasmid
• blandm-1
• rmtc