Carbapenem-resistant Klebsiella pneumoniae : the role of plasmids in emergence, dissemination, and evolution of a major clinical challenge

Introduction Klebsiella pneumoniae is a major agent of healthcare-associated infections and a cause of some community-acquired infections, including severe bacteremic infections associated with metastatic abscesses in liver and other organs. Clinical relevance is compounded by its outstanding propensity to evolve antibiotic resistance. In particular, the emergence and dissemination of carbapenem resistance in K. pneumoniae has posed a major challenge due to the few residual treatment options, which have only recently been expanded by some new agents. The epidemiological success of carbapenem-resistant K. pneumoniae (CR-Kp) is mainly linked with clonal lineages that produce carbapenem-hydrolyzing enzymes (carbapenemases) encoded by plasmids.