In vitro antimicrobial activity of sparfloxacin and its therapeutic efficacy on respiratory infections

The in vitro antimicrobial activity of sparfloxacin, a new quinolone agent for oral use, was measured and its therapeutic efficacy on respiratory infections was evaluated. The minimum inhibitory concentrations (MICs) of sparfloxacin (SPFX), ofloxacin (OFLX) and ciprofloxacin (CPFX) against 20 strains each of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens and Pseudomonas aeruginosa were determined by a micro-broth dilution method using the Dynatech MIC 2000 system. As shown by MICs, sparfloxacin was the most active of the 3 agents tested against Staphylococcus aureus, Escherichia coli and Enterobacter cloacae. Sparfloxacin was less active than ciprofloxacin, but more active than ofloxacin against Klebsiella pneumoniae, Serratia marcescens and Pseudomonas aeruginosa. A daily dose of 200-300 mg of sparfloxacin was given orally for 3-17 days (mean : 11.1 days) to 7 patients : 1 each with acute bronchitis, infected bronchiectasis and infection secondary to pulmonary emphysema, and 4 with acute pneumonia. The clinical effects were excellent in 1, good in 3 and poor in 2 cases. One case of pneumonia was excluded from clinical evaluation because of lack of symptom and sign of infection. Three strains of Haemophilus influenzae were identified as causative organisms. All of them were eradicated by sparfloxacin. Erythema and a transient elevation of the value of GPT were each observed in one patient. These adverse reactions disappeared after completion of the therapy. From the above results, we conclude that sparfloxacin is one of the most useful quinolone agents for oral use, and a first choice in the treatment of respiratory infections, especially in chronic cases.