Combined action of sulbenicillin and gentamicin.

Nine laboratory standard strains and 29 clinically isolated strains of Pseudomonas aeruginosa were employed for the studies of combined use of sulbenicillin and gentamicin in vitro. Increased antibacterial activity by the combined use of the two drugs over the activity of either drug alone was observed against all the strains tested. Bactericidal activity against P. aeruginosa N 18 was enhanced by combining the two drugs. Synergistic activity of the two drugs was also observed in protective studies against intraperitoneal infection in mice by several Pseudomonas strains.