Carbapenem Resistance-Encoding and Virulence-Encoding Conjugative Plasmids in Klebsiella pneumoniae.

Klebsiella pneumoniae has an exceptional ability to acquire exogenous resistance-encoding and hypervirulence-encoding genetic elements. In this review we trace the key evolutionary routes of plasmids involved in the dissemination of such elements; we observed diverse, but convergent, evolutionary paths that eventually led to the emergence of conjugative plasmids which simultaneously encode carbapenem resistance and hypervirulence. One important evolutionary feature of these plasmids is that they contain a wide range of transposable elements that enable them to undergo frequent genetic transposition, resulting in plasmid fusion and presumably better adaptation of the plasmid to the bacterial host. Identifying the key molecular markers of resistance and virulence-bearing conjugative plasmids allows improved tracking and control of the life-threatening carbapenem-resistant and hypervirulent strains of K. pneumoniae. K. pneumoniae has become one of the most important bacterial pathogens; it causes a high mortality rate in patients. K. pneumoniae has an exceptional ability to acquire exogenous resistance-encoding and hypervirulence-encoding genetic elements, and it has evolved rapidly in the past decade. In one evolutionary route, classical K. pneumoniae strains acquired different types of bla KPC -encoding plasmid and evolved to become carbapenem-resistant K. pneumoniae (CRKP). In another evolutionary route, classical K. pneumoniae strains have become hypervirulent K. pneumoniae (hvKP) through the acquisition of pLVPK-like virulence plasmids. One important evolutionary feature of these plasmids is that they contain a wide range of transposable elements that enable them to undergo frequent genetic transposition, resulting in plasmid fusion and presumably better adaptation of the plasmid to the bacterial host. In recent years, convergence of these two evolutionary paths has been observed in K. pneumoniae , resulting in the emergence of carbapenem-resistant and hypervirulent K. pneumoniae (CR-hvKP) due to plasmid recombination and fusion processes. Identifying the key molecular markers of resistance and virulence-bearing conjugative plasmids allows improved tracking and control of the life-threatening carbapenem-resistant and hypervirulent strains of K. pneumoniae. [ABSTRACT FROM AUTHOR]