Abstract
On the isoniazid resistant bacilli isolated from the pulmonary tuberculous patients, the catalase activity and virulence were examined.
The virulence was determined by macroscopic changes of various organs as were the viable units contained in the spleen of the guinea pigs at autopsy 8 weeks after subcutaneous injection of the bacilli.
In the 13 resistant strains used in this experiment, 100γ/ml isoniazid resistant strains showed negative catalase reaction and attenuated virulence, on the other hand the strains lower than 10γ/ml resistant had not always clear relation among them.
The guinea pigs were treated with INH given orally 4mg per day for 10 to 21 weeks after the subcutaneous inoculation of 0.1mg of Wy jml isoniazid resistant and catalase negative strains.
This treatment was more effective compared with untreated groups, but the virulence of bacilli, which were isolated immediately after the treatment for 21 weeks and 11 weeks after the treatment for 10 weeks, did not show any change.
