Antimicrobial activity of ceftolozane-tazobactam tested against Enterobacteriaceae and Pseudomonas aeruginosa collected from patients with bloodstream infections isolated in United States hospitals (2013-2015) as part of the program to assess ceftolozane-tazobactam susceptibility (PACTS) surveillance program. by Shortridge D, Pfaller MA, Castanheira M and Flamm RK published in Diagn. Microbiol. Infect. Dis.: in press, 2018.