Concurrent emergence of multidrug resistance and heat resistance by CTX‐M‐15 ‐encoding conjugative plasmids in K lebsiella pneumoniae

A plasmid‐encoded ClpK protein was recently identified as a predictor of a heat‐resistant phenotype in the opportunistic pathogen K lebsiella pneumoniae . This study was undertaken to evaluate the presence of the clpK gene in extended‐spectrum β‐lactamase ( ESBL )‐producing K . pneumoniae and to assess the probable co‐transfer of multi‐resistance with the heat resistance phenotype. A D anish collection of 80 ESBL ‐producing K . pneumoniae bloodstream infection isolates was screened for clpK by colony hybridization. Nineteen isolates (24%) were positive for clpK ; some of them representing major clones identified in D enmark. Among these, nine isolates belonged to a single K . pneumoniae CTX ‐M‐15 clone with sequence type ( ST )16 exhibiting a heat‐resistant phenotype. This clone has a multi‐hospital occurrence and has also been detected outside D enmark. Horizontal co‐transfer of multiple antibiotic resistances, including the CTX ‐M‐15 resistance determinant, and the heat resistance phenotype was observed. Thus, the clpK gene is harbored by different ESBL ‐producing K . pneumoniae isolates including a clone of ST 16 internationally spread. The co‐localization of clpK on transferable ESBL ‐encoding plasmids allowing co‐dissemination of multiple drug resistance with bacterial heat resistance is a highly interesting phenomenon that may further complicate the prevention of spreading of certain successful clones of multi‐resistant K . pneumoniae .