Presentation_1_Characterization of a mcr-1 and CRISPR-Cas System Co-harboring Plasmid in a Carbapenemase-Producing High-Risk ST11 Klebsiella pneumoniae Strain.pdf
We set out to study the prevalence of the mcr-1 gene in carbapenemase-producing Klebsiella pneumoniae (CPKP) strains, and to determine whether its presence is associated with a fitness cost. A total of 234 clinical CPKP isolates were collected from a tertiary medical center in Taiwan from January 2018 to January 2019. The mcr-1 and carbapenemase genes were detected by polymerase chain reaction (PCR) followed by Sanger sequencing. The mcr-1-positive carbapenemase-producing strain was characterized by whole genome sequencing, a plasmid stability test and a conjugation assay. In vitro growth rate and an in vivo virulence test were compared between the parental mcr-1-positive strain and its mcr-1 plasmid-cured strain. We identified only one mcr-1 positive strain (KP2509), co-harboring blaKPC–2 and blaOXA–48, among 234 (1/234, 0.43%) CPKP strains. KP2509 and its Escherichia coli mcr-1 transconjugant showed moderate colistin resistance (MIC = 8 mg/L). The mcr-1 is located on a large conjugative plasmid (317 kb), pKP2509-MCR, with three replicons, IncHI, IncFIB, and IncN. Interestingly, a complete Type IV-A3 CRISPR-Cas system was identified in pKP2509-MCR. Plasmid pKP2509-MCR was highly stable in KP2509 after 270 generation of passage, and the pKP2509-MCR cured strain PC-KP2509 showed similar growth rate and in vivo virulence in comparison to KP2509. The prevalence of mcr-1 in CPKP strains remains low in our center. Notably, we identified a large plasmid with multiple replicons containing both the mcr-1 and the Type IV-3A CRISPR-Cas genes. The further spread of this highly stable plasmid raises concern that it may promote the increase of mcr-1 prevalence in CPKP.
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References
- https://doi.org//10.1128/AAC.00317-17
- https://doi.org//10.1016/s1369-5274(99)00005-3
- https://doi.org//10.1016/j.ijantimicag.2016.06.023
- https://doi.org//10.1006/abio.1995.1220
- https://doi.org//10.1093/jac/dkx491
- https://doi.org//10.1093/cid/cix893
- https://doi.org//10.1016/j.cmi.2020.07.043
- https://doi.org//10.1089/crispr.2019.0048
- https://doi.org//10.1016/j.diagmicrobio.2017.09.016
- https://doi.org//10.1128/AAC.01075-16
- https://doi.org//10.1128/mSphere.00551-19
- https://doi.org//10.1093/jac/dky164
- https://doi.org//10.3389/fmicb.2019.02934
- https://doi.org//10.1093/gbe/evx192
- https://doi.org//10.1016/S1473-3099(15)00424-7
- https://doi.org//10.1038/nrmicro3569
- https://doi.org//10.1038/s41579-019-0299-x
- https://doi.org//10.3201/eid2404.171787
- https://doi.org//10.1093/jac/dky061
- https://doi.org//10.1093/femsre/fux013
- https://doi.org//10.3389/fmicb.2020.01937
- https://doi.org//10.1093/nar/gkz1197
- https://doi.org//10.1128/CMR.00064-16
- https://doi.org//10.1016/S1473-3099(16)30528-X
- https://doi.org//10.1128/IAI.00127-11
- https://doi.org//10.1089/mdr.2017.0400
- https://doi.org//10.1016/j.ijantimicag.2017.11.011
- https://doi.org//10.2147/IDR.S292820
- https://doi.org//10.1016/S1473-3099(16)30527-8
- https://doi.org//10.1093/nar/gkab149
- https://doi.org//10.1038/s41467-017-02149-0