Antibiotic policy and prescribing strategies for therapy of extended-spectrum β-lactamase-producing Enterobacteriaceae: the role of piperacillin–tazobactam

Therapy of infections caused by extended-spectrum β-lactamase (ESBL)-producing bacteria with an antimicrobial to which they are resistant results in treatment failure, higher cost and increased mortality. The CLSI recommends reporting ESBL-producing strains of Escherichia coli, Klebsiella spp. and Proteus spp. as resistant to all penicillin, true cephalosporin and monobactam antimicrobials, but as susceptible to β-lactam-β-lactamase inhibitor combinations, including piperacillin–tazobactam, when they test as such. Current literature supports the action of piperacillin–tazobactam against susceptible strains of ESBL-producing bacteria based on the structure–activity relationship between inhibitors and the ESBLs, as well as on recent clinical outcome studies.