Single Versus Combined Antibiotic Therapy for Gram-Negative Infections

OBJECTIVETo evaluate the available clinical data regarding single versus combination antimicrobial therapy for treatment of gram-negative infections, focusing on the more recent data in predominantly nonneutropenic hosts. In vitro and in vivo data regarding various antimicrobial combinations are also discussed.DATA SOURCESClinical trials, review articles, and meta-analyses were identified from a MEDLINE search (1960–July 2003). Special attention was given to clinical outcome trials performed since 1989. Search terms included gram-negative infections, drug synergism, Pseudomonas aeruginosa, monotherapy, combination therapy, carbapenems, β-lactams, cefepime, aminoglycosides, and fluoroquinolones.DATA SYNTHESISAlthough most of the studies were not randomized, double-blind, or controlled, the most recent literature indicates that monotherapy with agents that are active against isolated organisms, including P. aeruginosa, may be appropriate for most patients. Efficacy outcomes, including mortality, did not sig...