Tuberc Respir Dis.  1970 Dec;17(4):29-34. 10.4046/trd.1970.17.4.29.

The Virulence of M. tuberculosis Isolated in Korea, 1968

• KMID: 2529118
• DOI: http://doi.org/10.4046/trd.1970.17.4.29

Abstract

Mycobacterium tuberculosis collected during the first nationwide case finding campaign by sputum examination in Korea in 1968 was tested for virulence using mice. Fifty four isolations were made from newly discovered tuberculosis patients with a history of no previous chemotherapy. Thirty nine isolations were sensitive to antimicrobials, and 15 were resistant to INH, PAS, or Streptomycin. The reference strains of M. tuberculosis used for the study were H37R. from the Trudeau Institute, British and Japanese strains from the national institute of health, Japan, and Indian strains from the Madras chemotherapy center. 0. 1 mcg. of a bacterial suspension from each isolation was injected intravenously. The average viable unit of bacilli injected per dose was 26. 7 x 10⁵. The mortality rate was observed for eight weeks. The extent of pulmonary lesions was measured by Aoki’s standard. Weight ratios of body and lung were recorded. The findings were: 1) The mortality rates of mice inoculated by the 39 isolations ranged from 100% for 9 isolations or 23.1% to 0% for 8 isolations or 20.5%. The average mortality rate was 52.9% for the 39 isolations. This was markedly higher than the rate of 24.7% previously reported in Japan. 2) The degree of macroscopic lesions in the lungs measured from 2.1 to 7.0 (Aoki’s standard). The mean was 4. 7. 3) The weight ratios between body and lung ranged from 100 to 314 (Lung wt. mgms/ Body wt. gms. X10). 4) The majority of the 15 INH resistant isolations was lower in virulence than the sensitive isolations. 11 had negative catalase activity.