Characterization of a novel Tn 6485h transposon carrying both blaIMP-45 and blaAFM-1 integrated into the IncP-2 plasmid in a carbapenem-resistant Pseudomonas aeruginosa

Objectives: To characterize a carbapenem-resistant Pseudomonas aeruginosa (CRPA) with an IncP-2 plasmid containing a novel transposon, Tn 6485h , which carries both blaIMP-45 and blaAFM-1 . Methods: Antimicrobial susceptibility testing and filter mating experiment were performed on PA942.The stability of the plasmid carrying both blaIMP-45 and blaAFM-1 was carried out. We determined the growth rate of the transconjugant to investigate fitness cost. Additionally, whole-genome sequencing and genomic analysis were performed on PA942.Results: PA942 strain was resistant to most antibiotics except for ciprofloxacin and colistin. Bioinformatics analysis confirmed that PA942 contains an IncP-2 plasmid with a novel transposon Tn 6485h carrying both blaIMP-45 and blaAFM-1 . The plasmid pPA942-IMP45 can be transferred into recipient bacteria PAO1 Rif with an efficiency of 2.2 x 10 -7 and the transconjugant PAO1 Rif / pPA942-IMP45 can be stably inherited for 10 generations in the absence of antibiotics. Conclusion: We report a carbapenem-resistant P. aeruginosa strain with an IncP-2 plasmid containing a novel transposon, Tn 6485h , which carries both blaIMP-45 and blaAFM-1 . The IncP-2 plasmid and transposon Tn 6485h may contribute to the spread of MBL genes. Therefore, effective measures to prevent the spread of these plasmids should be taken.(c) 2023 The Authors. Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )