Piperacillin-tazobactam resistance in Klebsiella pneumoniae is often mediated by blaSHV amplification in a widespread plasmid

In this study, we aim to elucidate the molecular basis of piperacillin-tazobactam resistance through whole-genome analysis of ESBL-negative clinical isolates. We also characterizated in details plasmidic supports and, through large-scale genome database screening, explore the possible existence of an epidemic plasmid driving resistance dissemination.