Antimicrobial activity of ceftazidime/avibactam, ceftolozane/tazobactam and comparator agents against from cystic fibrosis patients.

OBJECTIVES

To evaluate the antimicrobial susceptibility patterns of isolates collected from the lower respiratory tract of cystic fibrosis (CF) patients.

METHODS

We susceptibility tested 273 contemporary isolates from 39 hospitals worldwide (17 countries) by the reference broth microdilution method.

RESULTS

Ceftazidime/avibactam [MIC, 2/8 mg/L; 96.0% susceptible (S)] was the most active agent, followed by ceftolozane/tazobactam (MIC, 1/4 mg/L; 90.5% S), ceftazidime (MIC, 2/>32 mg/L; 80.6% S), piperacillin/tazobactam (MIC, 4/128 mg/L; 80.2% S) and tobramycin (MIC, 2/>16 mg/L; 76.6% S). Ceftazidime/avibactam retained activity against isolates non-susceptible to meropenem (86.5% S to ceftazidime/avibactam), piperacillin/tazobactam (85.2% S to ceftazidime/avibactam) or ceftazidime (79.2% S to ceftazidime/avibactam). MDR phenotype was observed among 36.3% of isolates, and 88.9% and 73.7% of MDR isolates were susceptible to ceftazidime/avibactam and ceftolozane/tazobactam, respectively. Against isolates non-susceptible to meropenem, piperacillin/tazobactam and ceftazidime, susceptibility rates were 78.9% for ceftazidime/avibactam and 47.4% for ceftolozane/tazobactam. Ceftazidime/avibactam was active against 65.4% of ceftolozane/tazobactam-non-susceptible isolates and ceftolozane/tazobactam was active against 18.2% of ceftazidime/avibactam-non-susceptible isolates.

CONCLUSIONS

Ceftazidime/avibactam and ceftolozane/tazobactam exhibited potent and broad-spectrum activity against isolated from CF patients worldwide, but higher susceptibility rates for ceftazidime/avibactam compared with ceftolozane/tazobactam were observed among the resistant subsets. Ceftazidime/avibactam and ceftolozane/tazobactam represent valuable options to treat CF pulmonary exacerbations caused by .