Ticarcillin for treatment of serious infections with gram-negative bacteria.

Ticarcillin, a semisynthetic penicillin, was evaluated in the treatment of 75 serious gram-negative infections, 50 of which were caused by Pseudomonas aeruginosa. The overall rate of response was 81%. Septicemia and urinary tract infections responded more frequently (93%) than infections of the lower respiratory tract (71%). Response to therapy was comparable to results achieved previously with larger doses of carbenicillin. Response was not correlated with levels of drug in serum. Patients with nonfatal underlying disease were the most likely to respond to treatment. Ticarcillin-resistant organisms were isolated during therapy in 39% of the cases, and superinfection occurred in 12%. Colonization with resistant organisms did nto correlate with success or failure of therapy, severity of underlying disease, or levels of ticarcillin in serum. The clinical response and incidence of colonization were not altered by concurrent use of gentamicin, nor was the development of superinfection affected. Combination of ticarcillin and gentamicin in treatment of 19 patients did not produce toxicity. Eosinophilia, phlebitis, and hypokalemia occurred, as seen with carbenicillin, but major toxicity was not encountered.