Genomic analysis of MCR-8 and NDM-5 coproducing Klebsiella pneumoniae, an important ESKAPE pathogen, isolated from an ICU inpatient from a tanker explosion incident

• Scientific Questions Burn patients are highly susceptible to multidrug-resistant pathogens. Carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the most important pathogens in burn patients. Therefore, explore the transmission of CRKP in the burn patients, and especially co-producing mobile colistin resistance (MCR)-8 and New Delhi metallo-β-lactamase (NDM)-5 is crucial. • Evidence before This Study CRKP is known to pose a significant threat to burn patients due to exhibiting multidrug resistance and high transmissibility. Previous studies have identified several NDM variants, with NDM-1 and NDM-5 being the most common, while the emergence of mcr-1 has indicated the spread of colistin resistance. • New Findings The study identified six ST15 strains and one ST273 strain co-harboring bla NDM-5 and mcr-8.1 . Genomic analysis revealed that ST15 strains carried the Tn1722- bla KPC-2 transposon and a mutated rmpA2 gene, while ST273 strains exhibited colistin resistance. Four complete plasmids were discovered, with ST15 strains harboring bla KPC-2 and rmpA2 , and ST273 carrying mcr-8.1 and bla NDM-5 , suggesting potential for horizontal transfer and possible clonal expansion. • Significance of the Study This research uncovers the genetic complexity and high transmissibility of CRKP strains in the burn patients, emphasizing the urgent need for systematic surveillance and intervention to prevent the spread of emerging resistance determinants in both clinical and community settings. It provides valuable insights into the molecular mechanisms of multidrug resistance, aiding in the development of more effective infection control strategies. The findings underscore the need for continued research and monitoring to limit the dissemination of potentially high-risk CRKP clones, ensuring public health safety. Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a critical threat to burn patients due to multidrug resistance and high transmissibility. We analyzed CRKP isolates from 15 severe burn victims of a tanker explosion in China, identifying six ST15 strains and one ST273 strain co-harboring bla NDM-5 and mcr-8.1 . Genomic analysis revealed that ST15 (KP1) carried the Tn1722-bla KPC-2 transposon and a mutated rmpA2 gene, whereas ST273 (KP6) exhibited colistin resistance. Whole-genome sequencing identified four complete plasmids: ST15 strains harbored bla KPC-2 and rmpA2 , and ST273 carried mcr-8.1 and bla NDM-5 on separate plasmids. The mcr-8.1 gene resided on an IncFII(K) / IncFIA(HI1) plasmid with a conserved resistance region, suggesting horizontal transfer potential, while bla NDM-5 on IncX3 plasmids indicates clonal expansion. These findings reveal the genetic complexity and high transmissibility of CRKP strains and highlight the urgent need for systematic surveillance to prevent the spread of emerging resistance determinants.