A comparative study of ticarcillin plus tobramycin versus carbenicillin plus gentamicin for the treatment of serious infections due to gram-negative bacilli.

The combination of ticarcillin plus tobramycin (TT) or carbenicillin plus gentamicin (CG) 
was used to treat 82 patients with severe systemic gram-negative infection 
in a prospective, randomized study. Pseudomonas aeruginosa was the primary pathogen 
in 7 (93 per cent) of these patients. Patients treated with 
TT responded more frequently (92 per cent or 37 of 40) 
than patients treated with CG (71 per cent or 30 of 
42) (p is less than 0.05). This difference was primarily due 
to a greater response to TT in patients with pulmonary infections 
(93 per cent versus 68 per cent) and infections due to 
Pseudomonas (92 per cent versus 70 per cent). Severity of underlying 
disease was also an important determinant of response. Except for a 
greater incidence of hepatotoxicity with CG (23 per cent versus 3 
per cent; p is less than 0.02), there was no difference 
in toxicity, colonization with drug-resistant microorganisms or superinfection between the two 
treatment groups. The combination of TT appears to be superior to 
CG for the treatment of pulmonary infections due to Pseudomonas aeruginosa. 
