Ceftolozane/tazobactam: a novel antipseudomonal cephalosporin and β-lactamase-inhibitor combination Mai-Chi Hong1, Donald I Hsu1,2, Mark Bounthavong3,41Department of Pharmacy Practice and Administration, Western University of Health Sciences, Pomona, 2Department of Pharmacy, St Joseph Hospital, Orange, 3Department of Pharmacy, Veterans Affairs San Diego Healthcare System, San Diego, 4Department of Pharmacy Practice, University of California, San Diego, CA, USAAbstract: The management of infections caused by multidrug-resistant Gram-negative bacteria, particularly Pseudomonas aeruginosa, continues to be a significant challenge to clinicians. Ceftolozane/tazobactam is a novel antibacterial and β-lactamase-inhibitor combination that has shown appreciable activity against wild-type Enterobacteriaceae and potent activity against P. aeruginosa. Moreover, ceftolozane/tazobactam has not demonstrated cross-resistance to other antimicrobial classes, particularly those affected by extended-spectrum β-lactamases, AmpC β-lactamase, a loss in porin channels, or the overexpression of efflux pumps in P. aeruginosa. Ceftolozane/tazobactam has completed two Phase II clinical trials in complicated intra-abdominal and complicated urinary tract infections. A Phase III, multicenter, prospective, randomized, open-label study has been initiated to evaluate the safety and efficacy of ceftolozane/tazobactam versus piperacillin/tazobactam for the treatment of ventilator-associated pneumonia. A Medline search of articles from inception to May 2013 and references for selected citations was conducted. Data from abstracts presented at conferences were also appraised. This article reviews the antimicrobial, pharmacokinetic, and pharmacodynamic profile of ceftolozane/tazobactam, and discusses its potential role in therapy.Keywords: CXA-201, CXA-101, FR264205, Pseudomonas aeruginosa