{"doi":"10.3389/fmicb.2021.762947","title":"Characterization of a mcr-1 and CRISPR-Cas System Co-harboring Plasmid in a Carbapenemase-Producing High-Risk ST11 Klebsiella pneumoniae Strain","abstract":"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 bla KPC– 2 and bla OXA– 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.","journal":"Frontiers in Microbiology","year":2021,"id":202941,"datarank":0.29188652235829704,"base_score":1.9459101490553132,"endowment":1.9459101490553132,"self_citation_contribution":0.29188652235829704,"citation_network_contribution":0.0,"self_endowment_contribution":0.29188652235829704,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":6,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9127,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":784186,"name":"Sheng-Hua Chou","orcid":null,"position":1,"is_corresponding":false},{"id":783572,"name":"Po-Han Huang","orcid":"0000-0002-8899-9132","position":2,"is_corresponding":false},{"id":783573,"name":"Tsuey‐Ching Yang","orcid":"0000-0003-4111-6870","position":3,"is_corresponding":false},{"id":784187,"name":"Yu-Fan Juan","orcid":null,"position":4,"is_corresponding":false},{"id":231558,"name":"Barry N. Kreiswirth","orcid":"0000-0002-0243-131X","position":5,"is_corresponding":false},{"id":783574,"name":"Yi‐Tsung Lin","orcid":"0000-0001-9940-7529","position":6,"is_corresponding":false},{"id":231557,"name":"Liang Chen","orcid":"0000-0001-5845-2235","position":7,"is_corresponding":false},{"id":784185,"name":"Yi-Hsiang Cheng","orcid":null,"position":0,"is_corresponding":true}],"reference_count":31,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:51:14.206397Z","pmid":"34777318","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}