Isolation of Hv-CRKP with co-production of three carbapenemases ( bla KPC , bla OXA-181 or OXA-232 , and bla NDM-1 ) and a virulence plasmid: a study from a Chinese tertiary hospital

The worldwide dissemination of isolates is a significant public health concern, as these organisms possess a unique capacity to acquire genetic elements encoding both resistance and hypervirulence. This study aims to investigate the epidemiological, resistance, and virulence characteristics of isolates that carry both virulence plasmids and genes in a tertiary hospital in China. A total of 217 clinical isolates of carbapenem-resistant (CRKP) were collected between April 2020 and March 2022. The antimicrobial susceptibility test was conducted to evaluate the drug resistance profile. All isolates were screened for the presence of genes encoding carbapenemases ( , , , , and ), ESBLs genes ( , , ), and virulence plasmid pLVPK-borne genes ( , , , , and ) using polymerase chain reaction (PCR) amplification. Clonal lineages were assigned using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The plasmid incompatibility groups were identified using PCR-based replicon typing (PBRT). The transferability of carbapenemase-encoding plasmids and pLVPK-like virulence plasmids was assessed via conjugation. The plasmid location of was determined using S1-Pulsed Field Gel Electrophoresis (S1-PFGE) and southern blotting hybridization. The virulence potential of the isolates was assessed using the string test, capsular serotyping, serum killing assay and a Galleria mellonella larval infection model. Of the 217 CRKP clinical isolates collected, 23% were identified as carrying genes. All isolates exhibited resistance to commonly used clinical antimicrobial agents, except for ceftazidime/avibactam, colistin, tigecycline, trimethoprim-sulfamethOXAzole, polymyxin B, and nitrofurantoin. The main common OXA-48-like carbapenemase enzymes were found to be and . MLST and PFGE fingerprinting analysis revealed clonal transmission and plasmid transmission. OXA-48-like producing CRKP isolates mainly clustered in K64 ST11 and K47 ST15. Results of the string Test, serum killing assay ( ) and infection model ( ) indicated hypervirulence. PBRT showed that the and producing hypervirulent carbapenem-resistant (Hv-CRKP) were mainly carried on ColE-type, IncF, and IncX3. Eight clinical isolates of hv-CRKP were identified as carrying three carbapenem-resistant genes ( , , and ). Moreover, Southern blotting hybridization revealed that all eight isolates had a pLVPK-like virulent plasmid (138.9-216.9 kb) with an uneven number and size of plasmid. In our investigation, we