結核菌の吸入感染に関する実験的研究

とくにINH耐性菌による感染とBCG免疫との関係

抄録

It is generally said that the virulence of the isoniazid highly resistant and catalase negative tubercle bacilli is attenuated. And it is also well known that the expression of the virulence is different by the infection's route.
There are only a few reports on the airborne infection of the isoniazid highly resistant tubercle bacilli. The authors studied the virulence of the isoniazid resistant and catalase negative tubercle bacilli using H37Rv which acquired the resistance to isoniazid of 50mcg per ml in vitro, and studied the effect of BCG vaccination on the airborne infection of H37Rv highly resistant to isoniazid (H37Rv INHR).
In the first experiment, the virulence of H37 Rv INHR was studied by the airborne infection, being compared with the virulence of H37Rv by the same method.
When the guinea pigs inhalated the susceptible bacilli to isoniazid (H37Rv), a good many tubercles involving the caseous centres were generated in their lungs.
On the other hand, in the case of the airborne infection of the highly resistant bacilli to isoniazid the number of tubercles in their lungs was less than the former case, and the histological changes were also a little weaker compared with those of the infection by the susceptible bacilli to isoniazid. As to the changes of the tracheal lymph-nodes, there was little difference between these two strains, that is, swelling and diffusecaseation of the tracheal lymph-nodes were found. By the quantative culture method it has been found that the number of viable bacilli in the lungs and spleens was much less in the animals infected with the isoniazid resistant strain than in the animals infected with the isoniazid susceptible strain.
In the second experiment the authors studied the effect of BCG vaccination for the airborne infection of isoniazid resistant tubercle bacilli. The number of tubercles generated in the lungs and the number of the viable bacilli in each organ were much less in BCG vaccinated animals than in non-vaccinated animals.
From these results the authors conclude as follows: It cannot be denied that the virulence of the isoniazid highly resistant and catalase negative strain is attenuated for the guinea pigseven by airborne infection, but it was not so much weakened as the authors had hitherto considered and BCG vaccination is very effective for the airborne infection of the isoniazid highly resistant tubercle bacilli.