The Brazilian Journal of Infectious Diseases The Brazilian Journal of Infectious Diseases
Braz J Infect Dis 2017;21:627-37 - Vol. 21 Num.6 DOI: 10.1016/j.bjid.2017.06.008
Original article
Ceftolozane-tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing healthcare-associated infections in Latin America: report from an antimicrobial surveillance program (2013–2015)
Michael A. Pfallera,b, Dee Shortridgea,, , Helio S. Sadera, Ana Galesc, Mariana Castanheiraa, Robert K. Flamma
a JMI Laboratories, North Liberty, IA, United States
b University of Iowa, College of Medicine, Iowa City, IA, United States
c Universidade Federal de São Paulo, São Paulo, SP, Brazil
Received 09 May 2017, Accepted 18 June 2017

This study evaluated the in vitro activity of ceftolozane-tazobactam and comparator agents tested against Latin American isolates of Enterobacteriaceae and Pseudomonas aeruginosa from patients with health care-associated infections. Ceftolozane-tazobactam is an antipseudomonal cephalosporin combined with a well-established β-lactamase inhibitor.

A total of 2415 Gram-negative organisms (537 P. aeruginosa and 1878 Enterobacteriaceae) were consecutively collected in 12 medical centers located in four Latin American countries. The organisms were tested for susceptibility by broth microdilution methods as described by the CLSI M07-A10 document and the results interpreted according to EUCAST and CLSI breakpoint criteria.


Ceftolozane-tazobactam (MIC50/90, 0.25/32μg/mL; 84.2% susceptible) and meropenem (MIC50/90, ≤0.06/0.12μg/mL; 92.6% susceptible) were the most active compounds tested against Enterobacteriaceae. Among the Enterobacteriaceae isolates tested, 6.6% were carbapenem-resistant Enterobacteriaceae and 26.4% exhibited an extended-spectrum β-lactamase non-carbapenem-resistant phenotype. Whereas ceftolozane-tazobactam showed good activity against extended-spectrum beta-lactamase, non-carbapenem-resistant phenotype strains of Enterobacteriaceae (MIC50/90, 0.5/>32μg/mL), it lacked useful activity against strains with a (MIC50/90, >32/>32μg/mL; 1.6% S) carbapenem-resistant phenotype. Ceftolozane-tazobactam was the most potent (MIC50//90, 0.5/16μg/mL) β-lactam agent tested against P. aeruginosa isolates, inhibiting 86.8% at an MIC of ≤4μg/mL. P. aeruginosa exhibited high rates of resistance to cefepime (16.0%), ceftazidime (23.6%), meropenem (28.3%), and piperacillin-tazobactam (16.4%).


Ceftolozane-tazobactam was the most active β-lactam agent tested against P. aeruginosa and demonstrated higher in vitro activity than available cephalosporins and piperacillin-tazobactam when tested against Enterobacteriaceae.

Ceftolozane-tazobactam, Drug resistance, Enterobacteriaceae, P. aeruginosa, Latin America, Surveillance
Braz J Infect Dis 2017;21:627-37 - Vol. 21 Num.6 DOI: 10.1016/j.bjid.2017.06.008