STUDIES ON PIVMECILLINAM

Abstract

On a new β-lactam antibiotic, pivmecillinam, some studies were performed and the following results were obtained.
1. The susceptibility of various species of gram-negative bacilli isolated from clinical specimens was tested against mecillinam comparing with those of ampicillin. It was observed that the MIC values were apt to be influenced by inoculum size and sometimes colonies were found on the plates containing with higher concentration of drug, skipping one or more plates in the graded series of two fold dilution. The susceptibilities of some strains of Klebsiella and E. coli using inoculum size of 100 fold dilution of overnight culture were considerably excellent comparing with that obtained by original culture.
2. The conversion of pivmecillinam to mecillinam in broth and pH 7.0 phosphate buffer solution was confirmed using bioautography. The mixing of pivmecillinam with organs' homogenates of various animal species led to the production of mecillinam at different speeds. Especially the speed was the slowest in case of dog intestine.
3. Clinically pivmecillinam was administered to a total of 11 cases, that is, 3 of pneumonia, 3 of tonsillitis and 5 of urinary tract infection. The results were judged as effective in 6 cases, fair in 3 and poor in 2. Though urticaria-like eruption was observed transiently in one case, it subsided during the continuation of administration without the confirmation of causative agent. Various laboratory findings obtained before and after the medication revealed no abnormal values in any item of examination.