Abstract
Carfecillin has an antimicrobial spectrum similar to that of carbenicillin. Carfecillin provides more potent antimicrobial activity than carbenicillin against Staph. aureus and Str. faecalis isolated from patients. As carbenicillin is easily liberated from carfecillin in neutral and alkaline solutions and conventional media at 37°C, it is not certain whether the antimicrobial activity of carfecillin is based on the ester substance. The hydrolysis of carfecillin in broth cultures differed according to the kind of bacteria and the hydrolytic activity of the sera differed among species of animals. The activity was the most potent in mice and rats, followed by man, rabbits and dogs. When the hydrolytic activity of rat tissue homogenates was compared with that of serum, the hydrolytic activity of the serum was the highest, followed in the tissues by liver, kidneys, lungs and small and large intestines. After repeated massive doses of carfecillin no changes in hydrolytic activity of rat tissues were observed. Given orally to mice, the protecting effect of carfecillin against experimentally induced infections varied according to the kind of bacteria, and was comparable to that of carbenicillin given subcutaneously.
