Systematic Veterinary Bacteriology and Mycology

RESISTANCE

• The vegetative bacilli are destroyed at 60°C in 30mts.
• In the carcases of animals, the bacilli remain viable in the bone marrow for a week and in the skin for two weeks.
• Normal heat fixation of smears may not kill the bacilli in blood film.
• The spores are highly resistant to drying, heat, cold and disinfectants. Spores remain viable for many years in soil, water and animal hides and products.
• Spores have been isolated from naturally infected soil as long as 60years.
• They resists dry heat at 140°C for 2-3hrs and boiling for 10mts.
• They survive in 5% phenol for weeks. Spores can be killed at 120°C for 10min and 4% KMnO4 treatment for 15mts.
• Destruction of the spores in animal products is achieved by HCHO.
• Treat 2% solution of HCHO at 39-40°C for 20mts for disinfection of wool and as 0.25% at 60°C for 6 hrs for animal hair and bristles. This process is called as duckering.
• The anthrax bacillus is susceptible to sulphonamides, penicillin, erythromycin, streptomycin, tetracycline and chloramphenicol.