Microbiological activity of ceftolozane/tazobactam, ceftazidime, meropenem, and piperacillin/tazobactam against Pseudomonas aeruginosa isolated from children with cystic fibrosis

The activity of ceftolozane/tazobactam was tested against 50 nonduplicate Pseudomonas aeruginosa from 18 cystic fibrosis children collected in 2012-2014. These isolates were multidrug resistant with susceptibility to meropenem, ceftazidime, and piperacillin/tazobactam of 46%, 58%, and 50%, respectively. Ceftolozane/tazobactam was the most active with MIC50, MIC90, and percent susceptibility of 2 mg/L, 8 mg/L, and 86%.