The co-existence of plasmid-mediated extended-spectrum β-lactamase blaCTM-X-167 gene and novel tigecycline resistance gene tet(A)-v in carbapenem-resistant Klebsiella pneumoniae

Abstract Carbapenem-resistant Enterobacterales (CRE) pose a serious clinical and therapeutic challenge, impose a substantial economic burden, and frequently cause severe infections and poor clinical outcomes, particularly in immunocompromised patients. In this study, we report a case of carbapenem-resistant Klebsiella pneumoniae (CRKP) carrying bla CTX-167 and tet (A)-v from a urine sample of a leukemia patient following bone marrow transplantation, chemoradiotherapy, long-term intubation, multi-antibiotic combination therapy, and prolonged ICU hospitalization. Whole-genome sequencing revealed that these resistance genes are located on a conjugable fusion plasmid of the IncFII(K)-IncQ1 type, exhibiting high amino acid identity and coverage with plasmids from clinical and environmental isolates of K. pneumoniae and Shigella flexneri. The presence of IS 26 and IS Ecp1 likely mediates the mobilization of bla CTX-M-167 , thereby enhancing its potential for horizontal transfer. These findings highlight the urgent need for strengthened surveillance in healthcare settings, particularly for high-risk and multidrug clones.