STUDY OF THE VIRULENCE OF ISONIAZID-RESISTANT TUBERCLE BACILLI IN GUINEA PIGS AND MICE - A PRELIMINARY REPORT

Abstract
Tubercle bacilli resistant to 25 and 50 gamma of isoniazid no longer cause progressive visceral disease in the guinea pig. This study indicates that strains resistant to as little as 0.2 gamma of isoniazid/ml. are attenuated in virulence. Variations in laboratory methodology may explain the discrepancies in the literature concerning the virulence in guinea pigs of isoniazid-resistant tubercle bacilli.