The early bactericidal activity of ciprofloxacin in patients with pulmonary tuberculosis

The early bactericidal activity (EBA) of ciprofloxacin (CIP) was measured in 80 patients with previously untreated, smear-positive pulmonary tuberculosis by counting viable bacilli in sputum collections during the first 2 d of treatment. Groups of about 10 patients were treated daily with graded doses of CIP or with 300 mg isoniazid or with no drug. The mean EBA, defined as the fall in log CFU/ml sputum/d, increased from -0.011 in the no drug group to 0.046, 0.092, 0.121, and 0.205 in the groups receiving 250, 500, 1,000, or 1,500 mg CIP, respectively, a highly significant trend. These results demonstrate the antimycobacterial activity of CIP in high dosage, though the mean EBAs of 0.55 and 0.66 in two groups receiving isoniazid were much higher.