Laboratory and clinical studies on ritipenem acoxil

We evaluated the in vitro antimicrobial activity and the clinical efficacy of ritipenem acoxil, a newly developed broad-spectrum penem, and obtained the following results. 1. Anitimicrobial activity: Minimal inhibitory concentrations (MICs) of ritipenem, imipenem, cefaclor, cefixime, cefteram, and cefotiam against 515 clinical isolates including 16 different species were determined by the microbroth dilution method. Ritipenem showed excellent antimicrobial activity against gram-positive and -negative bacteria. The MIC values of ritipenem against gram-positive bacteria were the best among the antibiotics tested. Against gram-negative bacteria the antimicrobial activity was slightly inferior to that of imipenem, but superior to those of the other antibiotics tested. 2. Clinical efficacy and adverse reactions: 15 patients with respiratory tract infection were treated with ritipenem acoxil, and the overall efficacy rate was 78.6%(excellent in 2 cases, good in 9, fair in 1, poor in 2, unknown in 1). Regarding adverse reactions, mild diarrhea was observed in one patient. Abnormal laboratory findings were observed in 2 cases (eosinophilia and thrombocytosis), but were mild and transient. From these data, we conclude that ritipenem acoxil is a useful antibiotic for the treatment of respiratory tract infectious diseases.