IN VITRO AND IN VIVO ANTIBACTERIAL ACTIVITY OF TA-058

Abstract

A semisynthetic penicillin, TA-058, is a derivative of amoxicillin. In vitro and in vivo antibacterial activities of TA-058 against gram-positive and gram-negative bacteria were compared with mainly ampicillin and piperacillin. The results are summarized as follows.
1) TA-058 possesses a broad spectrum of in vitro antibacterial activity against gram-positive and gram-negative bacteria.
2) In vitro antibacterial activites against gram-positive and gram-negative bacteria were compared using 1412 clinical isolates of 21 species of bacteria. TA-058 was as active as piperacillin against P. mirabilis and H. infiuenzae, but not against other bacteria.
3) Greater bactericidal activity toward the three strains, i. e., S. aureus, E. coli and P. aeruginosa, was demonstrated with TA-058 than with ampicillin and piperacillin.
4) TA-058, like penicillin G, was hydrolyzed by penicillinase. TA-058, ampicillin and piperacillin were more stable against cefuroximase and cephalosporinase than against penicillinase.
5) In vivo antibacterial activities of TA-058, ampicillin and piperacillin were compared, using systemic infections of mice with S. aureus, E. coli, K. pneumoniae, S. marcescens, P. aeruginosa and P. mirabilis. The 50 % effective doses of TA-058 were lower than those of piperacillin against E. coli and P. mirabilis.