Basic and clinical studies on S-1108

We performed basic and clinical studies on S-1108, a new oral cephalosporin antibiotic, with the following results. 1) Antimicrobial activity The MICs of S-1006, the active substance of S-1108, were determined with an inoculum size of 10⁶ cells/ml. The MIC₉₀ of S-1006 was 0. 78μg/ml for Staphylococcus aureus, 100< for Enterococcus faecalis, 0.78 for Escherichia coli, 6.25 for Klebsiella pneumoniae, 25 for Enterobacter spp., 50 for Serratia marcescens and Citrobacter freundii, and 100 for Pseudomonas aeruginosa. Its activity against S. aureus was greater than that of the new oral cephems. On the other hand, its activity against gram-negative bacilli was the same as that of the new oral cephems and there were few strains highly-resistant to S-1006. 2) Clinical efficacy Four patients with pneumonia, 2 with acute bronchitis, 5 with chronic bronchitis, 2 with tonsillitis, and 1 with cystitis were treated with S-1108, The patients were treated with a daily dose of 150-600 mg for 2-40 days. The clinical response was excellent in 3, good in 5, fair in 3, poor in 1, and unknown in one patient. The efficacy rate was 69.3%. Adverse reactions were dysphoria (1 patient), and swelling of the vulva and nipple (1 patient), but there were no changes in the laboratory findings.