ANTIBACTERIAL ACTIVITY OF ENVIOMYCIN FOR ATYPICAL MYCOBACTERIA

2. Animal Experiments

Abstract

Antibacterial activity in vitro of EVM for atypical mycobacteria was already reported. In this report antibacterial activity in vivo was studied using mice.
Two strains of Miura and Brownell were chosen from M. kansasii and two strains of Yamawaki and Battey 100616 from M. intracellulare.
Two strains of M. kansasii were sensitive to 5μg/ml of EVM in Dubos liquid media. Strain Yamawaki of M. intracellulare was resistant incompletely to 20μg/ml, and Strain Battey 100616 was sensitive to 5μg/ml.
CF₁ mice were employed for M. kansasii, Balb/c and nu/nu mice were used for M. intracellulare.
Each mouse was injected 4mg or 8mg of EVM subcutaneously for four weeks from one week after the intravenous challenge by atypical mycobacteria.All mice were killed one week after stopping treatment by EVM, and macroscopic changes and viable units in lungs and spleens were examined.
Results are shown in Tables 1, 2, 3, 4 and 5. Virulence of Strain Miura was rather strong to mice. Bacilli in lungs and spleens multiplied in untreated mice, but decreased remarkably by the daily subcutaneous injection of 4 mg of EVM.
Virulence of Strain Brownell was not so strong. EVM was effective also for the infection of Strain Brownell.
Virulence of both strains of M. intracellulare was generally weak for Balb/c mice, but Strain Yamawaki multiplied in nu/nu mice.
Bacilli in organs of the infected nude mice with Strain Yamawaki decreased remarkably especially in lung and also swelling of spleens was improved by treatment of 8 mg EVM for four weeks. It was thought from this result that the effect of EVM to Strain Yamawaki was not always parallel between in vitro and in vivo.
Battey strain of M. intracellulare did not multiply even in nude mice, but the decrease of bacilli was faster by EVM treatment than without treatment.