Efficacy of ceftazidime-avibactam in a rat intra-abdominal abscess model against a ceftazidime- and meropenem-resistant isolate of Klebsiella pneumoniae carrying blaKPC-2.

Efficacies of ceftazidime-avibactam (4:1 w/w) and ceftazidime were tested against ceftazidime-susceptible (blaKPC-2-negative), and meropenem- and ceftazidime-resistant (blaKPC-2-positive), Klebsiella pneumoniae in a 52-h, multiple dose, abdominal abscess model in the rat. Efficacies corresponded to minimum inhibitory concentrations (MICs) measured in vitro and were consistent with drug exposures modelled from pharmacokinetics in infected animals. The ceftazidime, ceftazidime-avibactam and meropenem control treatments were effective in the rat abscess model against the susceptible strain, whereas only ceftazidime-avibactam was effective against K. pneumoniae harbouring blaKPC-2.