LABORATORY AND CLINICAL STUDIES ON SBT/CPZ

Abstract

Laboratory and clinical studies on SBT/CPZ, a novel antibiotic which combine a broad-spectrum cephalosporin antibiotic, cefoperazone and a β-lactamase inhibitor, sulbactam developed by Pfizer Co. Ltd., were carried out and the results were as follows.
1) Antibacterial activity:
Minimum inhibitory concentrations (MICs) of SBT/CPZ against a total of 240 strains isolated from various specimens (Staphylococcus aureus 25, Citrobacter freundii 27, Enterobacter aerogenes 26, Enterobacter cloacae 27, Proteus rettgeri 7, Proteus inconstans 20, Proteus morganii 27, Escherichia coli 27, Klebsiella aerogenes 27, Serratiii marcescens 27) were compared with those of CPZ and SBT. MICs50 of SBT/CPZ against most of these organisms other than Serratia marcescens were somewhat inferior to those of CPZ. MICs100 of SBT/CPZ against Escherichia coli, Citrobacter freundii and Proteus species were superior to those of CPZ. SBT alone showed no remarkable antimicrobial activity against most of these organisms.
2) Serum and sputum levels in patients with chronic respiratory tract infections:
SBT/CPZ was administered by intravenous drip infusion at a dose of 2g to four patients. The peak serum levels were 71-130μg/ml for CPZ and 20-58μg/ml for SBT at the termination of infusion and the peak sputum levels were 5.67mu;g/ml for CPZ and 8.8μg/ml for SBT.
3) Clinical results:
Twenty patients with respiratory tract infections (chronic bronchitis 3, bronchiectasis 7, pulmonary cyst 2, pneumonia 6, lung abscess 1, pleuritis 1) were treated with SBT/CPZ by intravenous drip infusion at a dose of 1-2g once or twice a day for 7-14 days and over all efficacy rate was 80%. Adverse reaction was noted in one case with slight elevation of S-GOT and S-GPT.