Ceftolozane-tazobactam activity against Pseudomonas aeruginosa clinical isolates from US hospitals: Report from an antimicrobial surveillance program (PACTS, 2012-2015).

Abstract

The activity of ceftolozane-tazobactam was compared to the activity of 7 antimicrobials against 3,851 Pseudomonas aeruginosa isolates collected from 32 US hospitals in the Program to Assess Ceftolozane-Tazobactam Susceptibility from 2012-2015. Ceftolozane-tazobactam and comparator susceptibilities were determined using the CLSI broth microdilution method at a central monitoring laboratory. For ceftolozane-tazobactam, 97.0% of the isolates were susceptible. Susceptibilities of the other antibacterials tested were: amikacin, 96.9%; cefepime, 85.9%; ceftazidime, 85.1%; colistin, 99.2%; levofloxacin, 76.6%; meropenem, 81.8%; and piperacillin-tazobactam, 80.4%.Of the 699 (18.1%) meropenem nonsusceptible P. aeruginosa, 87.6% were susceptible to ceftolozane-tazobactam.Six hundred and seven isolates (15.8%) were classified as multidrug-resistant (MDR), and 363 (9.4%) were classified as extensively drug resistant. Only 1 isolate was considered pan-drug resistant, which was resistant to all tested agents, including colistin. Of the 607 MDR isolates, 84.9% were ceftolozane-tazobactam susceptible and 76.9% of XDR isolates were ceftolozane-tazobactam susceptible. In vitro activity against drug resistant P. aeruginosa indicates ceftolozane-tazobactam may be an important agent in treating serious bacterial infections.