1824. Ceftolozane/Tazobactam Activity Tested Against Bacterial Bloodstream Isolates from Multiple Infection Sources
Session: Poster Abstract Session: Antibacterial Susceptibility Surveillance
Saturday, October 29, 2016
Room: Poster Hall
  • 150102087_Tol Taz BSI_L2d_FINAL.pdf (419.4 kB)
  • Background: Ceftolozane/tazobactam (C/T) is approved by the US-FDA for the treatment of intra-abdominal infections and complicated urinary tract infections, including pyelonephritis. We evaluated the activity of C/T and comparators against Enterobacteriaceae (ENT) and Pseudomonas aeruginosa (PSA) bloodstream infection (BSI) isolates stratified by infection source (where known).

    Methods: 12,204 ENT and 1,541 PSA BSI clinical isolates collected worldwide (from North America, Europe and Asia-Western Pacific) from 20112015 were susceptibility (S) tested by reference broth microdilution methods against C/T (TAZ at fixed 4 µg/mL) and comparators.  CLSI breakpoints were applied for C/T (ENT, ≤2 µg/mL; PSA, ≤4 µg/mL) and comparator compounds.

    Results: C/T inhibited 93.2% of all ENT and 90.7% of all PSA BSI isolates at the CLSI breakpoints (Table).  Against PSA BSI isolates derived from various identified infection sites, C/T S ranged from 80.8% [skin and skin structure infection (SSSI)] to 93.7% (urinary tract infection; UTI), and C/T activity was markedly superior to meropenem (MEM) overall (90.7 vs. 75.6% S for all PSA isolates) and against each of the isolate subsets.  C/T was also very active against ENT isolates derived from multiple sites of infection [%S range, 84.3 (lower respiratory tract; LRT) to 95.6% (UTI)].  The only two infection sites for which ENT isolates exhibited S <90% were intravenous/IV line (88.2% S) and LRT (84.3% S), and these constituted only 9.7% of all ENT isolates. Notably, C/T was more active than piperacillin/tazobactam (P/T) against the overall ENT isolate set (93.2% vs. 88.7% S) and against the isolate subsets from each site of infection. 

    Conclusion: C/T was active against a large worldwide collection of ENT (93.2% S, CLSI) and PSA (90.7% S, CLSI) BSI isolates collected 2011-2015, regardless of infection source.  Among the antimicrobials tested here, C/T was the most active β-lactam against PSA and, except for the carbapenems, was also the most active β-lactam against ENT. C/T may represent a valuable treatment option for BSI caused by Gram-negative pathogens.





    Leonard R. Duncan, Ph.D., Helio S. Sader, MD, PhD, Robert K. Flamm, Ph.D. and Mariana Castanheira, PhD, JMI Laboratories, Inc., North Liberty, IA


    L. R. Duncan, Cubist Pharmaceuticals, Inc.: Research Contractor , Research grant

    H. S. Sader, Cubist Pharmaceuticals, Inc.: Research Contractor , Research grant

    R. K. Flamm, Cubist Pharmaceuticals, Inc.: Research Contractor , Research grant

    M. Castanheira, Cubist Pharmaceuticals, Inc.: Research Contractor , Research grant

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.