Infection and Drug Resistance (Jul 2020)
High Prevalence of 16S rRNA Methyltransferase Genes in Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates Associated with Bloodstream Infections in 11 Chinese Teaching Hospitals
Abstract
Xiaofei Shen, 1 Li Liu, 2 Jingyi Yu, 2 Wenxiu Ai, 1 Xingwei Cao, 3 Qing Zhan, 4 Yinjuan Guo, 5, 6 Liangxing Wang, 1 Fangyou Yu 5, 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 Wang; Fangyou Yu Email [email protected]; [email protected]: The 16S rRNA methylase-mediated high-level resistance to aminoglycosides has become a great concern. The purpose of the study was to investigate the occurrence of 16S rRNA methyltransferase (RMTase) genes in carbapenem-resistant Klebsiella pneumoniae (CRKP) clinical isolates associated with bloodstream infections (BSIs) in China.Methods: From July 2015 to December 2018, a total of 137 unique CRKP clinical isolates associated with BSIs were collected from 11 Chinese teaching hospitals. PCR and DNA sequencing were used to identify 16S RMTase genes. Whole-genome sequencing (WGS) was performed on all CRKP clinical isolates. Relevant information was extracted from WGS data (antibiotic resistance determinants, K-type and wzi allelic types). All 16S RMTase-producing CRKP clinical isolates were characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE).Results: In this study, 137 CRKPs were found to harbor at least one carbapenemase gene. Among 137 CRKPs, 78 (56.9%, 78/137) were positive for 16S RMTase genes (5 for armA, 70 for rmtB, 3 for both armA and rmtB) and highly resistant to gentamicin and amikacin (MICs ≥ 256 mg/L). Seventy-five isolates harboring 16S RMTase genes also produced ESBLs. In this study, 5 sequence types (STs) and 6 capsule serotypes were found among 78 isolates positive for 16S RMTases genes, while 14 STs and 6 capsule serotypes were found among 59 isolates negative for 16S RMTases genes. Compared with the isolates negative for 16S RMTases genes, the STs and capsular serotypes of 16S RMTases-positive strains are more concentrated. Among 78 16S RMTases-positive strains, the most prevalent clone type is ST11-PFGE-B-KL64-wzi64 (62.8%, 49/78), which mainly carries the rmtB and blaKPC genes and is distributed in 7 provinces in China.Conclusion: A high prevalence of 16S RMTase genes was found among CRKP clinical isolates associated with BSIs from Chinese teaching hospitals, which was attributed to the dissemination of the ST11-PFGE-B-KL64-wzi64 clone.Keywords: CRKP, BSIs, 16S RMTase genes, aminoglycosides, molecular characteristics
