[Principles of antituberculosis chemotherapy and drug susceptibility tests]

Principles of antituberculosis chemotherapy and the present situation of the drug susceptibility testing in Japan were reviewed. There are three types of the bacteria in patients with tuberculosis: 1) actively replicating bacteria in cavities, 2) slowly replicating bacteria in caseous necrosis, and 3) fully dormant bacteria. The type 1) bacteria are the most vulnerable to all antituberculosis drugs, particularly INH, while the type 2) bacteria are susceptible to either RFP or PZA alone. In Japan, the drug susceptibility testing have been done by the absolute concentration method using Ogawa egg slants. However, there are many drawbacks pointed out in the system. Therefore, the Japanese society for tuberculosis has recommended a new testing system using the proportion method with the Ogawa medium since 1997.