Antileptospiral Activity of Several Antibiotics : Part 1. Results in vitro Examination

The in vitro activity of 17 antibiotics against five serovar strains of the genus Leptospira was determined. Cefotaxime and ceftizoxime were found to be more effective than other agents such as penicillin G or streptomycin in tests for minimal bactericidal concentrations, the value being from 0.1 to 25μg/ml. Also, cefotaxime at a concentration of 25μg/ml killed each L. copenhageni of various age within 48 hours while penicillin G (25units/ml) did not kill within five days. On the other hand, fosfomycin did not show the inhibitory action against Leptospira, indicating that this drug was hopeful to be an agent for the selective cultivation of Leptospira from contaminated materials.