Bacteriological and clinical studies of sulbenicillin.

A new semi-synthetic penicillin, sulbenicillin, was evaluated with regard to clinical effect on infections caused by Pseudomonas aeruginosa and other bacteria, serum concentrations obtained after intravenous administration and antibacterial spectrum, in comparison with the closely related antibiotic carbenicillin. The antibacterial spectra of sulbenicillin and carbenicillin were similar but the MIC values were lower for sulbenicillin against most of the bacterial strains tested. The serum concentrations obtained after administration of 5 g sulbenicillin were significantly higher than those obtained after 5 g carbenicillin although no significant differences in serum half-lives were observed. The clinical effect of sulbenicillin--alone or alternating with carbenicillin--on pseudomonas infections with varying localisation was found to be good in 11 and fair in 3 of 16 treated patients. Two treatment failures were cases of chronic wound infection. In addition to the pseudomonas infections, 9 of the patients also had concurrent infections with other bacteria, e.g. pencillinase-producing staphylococci and Klebsiella, and in all these cases bacterial growth was eliminated during therapy. No serious side effects were observed during sulbenicillin treatment but some of the patients developed massive growth of fungi in the urine, which disappeared after the treatment was stopped.