Yu Feng1, Lu Liu1, Alan McNally2, Zhiyong Zong3. 1. Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China; Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. 2. Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK. 3. Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China; Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China; Department of Infection Control, West China Hospital, Sichuan University, Chengdu, China; Center for Pathogen Research, West China Hospital, Sichuan University, Chengdu, China. Electronic address: zongzhiy@scu.edu.cn.
Abstract
OBJECTIVES: Here we report the finding of three copies of the blaKPC-2 gene on a plasmid in ST11 Klebsiella pneumoniae. METHODS: Carbapenem-resistant K. pneumoniae clinical strain WCHKP2 was subjected to whole-genome sequencing (WGS) using both a short-read Illumina HiSeq X10 platform and long-read MinION sequencer. Hybrid assembly was performed using Unicycler, and contigs were corrected using Pilon. Based on WGS, the sequence type (ST), capsular type, plasmid replicon type and plasmid multilocus sequence type were determined and virulence and antimicrobial resistance genes were identified. Mating was performed to identify a self-transmissible plasmid mediating carbapenem resistance. RESULTS: Strain WCHKP2 was resistant to imipenem [minimum inhibitory concentration (MIC)=64μg/mL] and meropenem (MIC=128μg/mL). Strain WCHKP2 had a 5477148-bp circular chromosome, two small ColRNAI-like plasmids (5596bp and 10060bp), and one large plasmid (177516bp, designated pKPC2_020002) containing an IncR and an IncFII replicon. Surprisingly, there were three copies of the blaKPC-2 carbapenemase gene on pKPC2_020002, which was not self-transmissible. Each of the blaKPC-2 genes was located in the same genetic context with insertion sequence ISKpn27 upstream and ISKpn6 downstream and bracketed by IS26. The three copies of the IS26-ISKpn27-blaKPC-2-ISKpn6-IS26 unit were present in tandem. CONCLUSION: Here we report the surprising co-existence of three copies of blaKPC-2 on an IncR/IncF plasmid due to the action of IS26. Multiple copies of IS26 are a key factor generating genetic plasticity and could mediate the multiplication of resistance genes.
OBJECTIVES: Here we report the finding of three copies of the blaKPC-2 gene on a plasmid in ST11 Klebsiella pneumoniae. METHODS:Carbapenem-resistant K. pneumoniae clinical strain WCHKP2 was subjected to whole-genome sequencing (WGS) using both a short-read Illumina HiSeq X10 platform and long-read MinION sequencer. Hybrid assembly was performed using Unicycler, and contigs were corrected using Pilon. Based on WGS, the sequence type (ST), capsular type, plasmid replicon type and plasmid multilocus sequence type were determined and virulence and antimicrobial resistance genes were identified. Mating was performed to identify a self-transmissible plasmid mediating carbapenem resistance. RESULTS: Strain WCHKP2 was resistant to imipenem [minimum inhibitory concentration (MIC)=64μg/mL] and meropenem (MIC=128μg/mL). Strain WCHKP2 had a 5477148-bp circular chromosome, two small ColRNAI-like plasmids (5596bp and 10060bp), and one large plasmid (177516bp, designated pKPC2_020002) containing an IncR and an IncFII replicon. Surprisingly, there were three copies of the blaKPC-2 carbapenemase gene on pKPC2_020002, which was not self-transmissible. Each of the blaKPC-2 genes was located in the same genetic context with insertion sequence ISKpn27 upstream and ISKpn6 downstream and bracketed by IS26. The three copies of the IS26-ISKpn27-blaKPC-2-ISKpn6-IS26 unit were present in tandem. CONCLUSION: Here we report the surprising co-existence of three copies of blaKPC-2 on an IncR/IncF plasmid due to the action of IS26. Multiple copies of IS26 are a key factor generating genetic plasticity and could mediate the multiplication of resistance genes.
Authors: Antoni P A Hendrickx; Fabian Landman; Angela de Haan; Dyogo Borst; Sandra Witteveen; Marga G van Santen-Verheuvel; Han G J van der Heide; Leo M Schouls Journal: Sci Rep Date: 2020-10-08 Impact factor: 4.379
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