Laboratory and clinical studies on pazufloxacin

We performed laboratory and clinical studies on pazufloxacin (PZFX), a new oral quinolonecarboxylic acid, with the following results. 1) Minimal inhibitory concentrations (MICs) of PZFX were measured for 238 clinical isolates, and compared with those of sparfloxacin (SPFX), levofloxacin (LVFX), tosufloxacin (TFLX) and ciprofloxacin (CPFX). Against methicillin-sensitive Staphylococcus aureus, the antimicrobial activity of PZFX was superior to that of CPFX. Many strains of methicillin-resistant S. aureus and Enterococcus faecalis were resistant to PZFX and other reference agents. The MICs of PZFX as well as other agents were relatively high for Pseudomonas aeruginosa. However, PZFX exhibited high activity against gram-negative bacteria with low MICs which were similar to those of CPFX. 2) The clinical efficacy of PZFX was evaluated for a total of 17 patients. Five with pneumonia, 3 with acute bronchitis, 2 with chronic bronchitis, 1 with acute tonsillitis, 2 with acute pharyngolaryngitis, 2 with acute cystitis, 1 with acute pyelonephritis and 1 with infected atheroma were treated with PZFX. The patients consisted of 9 males and 8 females aged 24 to 82 years, and most of them had underlying diseases. The patients were given a dose of 100 to 200 mg, b.i.d. or t.i.d. for 2 to 21 days. The clinical response was excellent in 3 cases, good in 8, fair in 4, poor in 1 and unknown in 1. The clinical efficacy rate was 69%. Bacteriologically, 7 strains isolated from infections were eradicated by treatment with PZFX. The side effects observed in 5 cases were nausea/vomiting, abdominal discomfort in 2 cases, anorexia/epigastralgia and general fatigue, respectively. Slight elevation of GOT, GPT and an increase in eosinophil count were observed in 2 cases.