In vitro activity of the ceftolozane-tazobactam agent against significant Gram-negative bacterial isolates obtained from South African public hospitals

Multi-drug resistant organisms complicate clinical care, prolong hospital stays and increase healthcare costs. Reports have shown relatively high resistance rates of Pseudomonas aeruginosa to the commonly used antipseudomonal agents such as piperacillin tazobactam, imipenem, ciprofloxacin, and ceftazidime. Also of concern are the high rates of resistance in the extended-spectrum-beta-lactamase Escherichia coli and Klebsiella pneumoniae. The current study aims to evaluate the activity of ceftolozane tazobactam against P. aeruginosa and the susceptibilities of extended-spectrum beta-lactamase-producing South African E. coli and K. pneumoniae to this drug. The secondary aim of the study is to elucidate the underlying molecular mechanisms of resistance to ceftolozane tazobactam.