The sensitivity and resistance of tubercle bacilli to conteben (TB1/698).

prolonged employment of chemotherapeutic agents. The last decade was the most brillian period in the history of the battle against tuberculosis by chemotherapy. Streptomycin (SM), paraaminosalicylic acid (PAS), 4-acetylaminobenzaldehyde thiosemicarbazone (TB1) and isonicotinic acid hydrazide (INAH) have been proved to be effective in the treatment of tuberculosis. Among them, the resistance development phenomenon of tubercle bacilli to streptomycin has been investigated in extreme detail by many workers. On the contrary, concerning the nature of resistance to other drugs, few bacteriological works have been reported in the completeness enough to be allowed to say something definite of its mechanisms or the association with clinical picture. In this connection, this laboratory attempted the investigation of the resistance of tubercle bacilli to those drugs (TB1, PAS and INAH). This paper deals with data with respect to TB1 as a preliminary report. Since the announcement by Domagk1 that the thiosemicarbazones are effective in vitro and in vivo against tubercle bacilli, TB1 has been used extensively also in this country. And it has been reported by some investigators2, 3, 4, 5, 6 that the tubercle bacillus isolated from the patients treated with TB1 was often resistant to the drug. On the other hand, however, Simmons and his colleagues7, and Mollov and his associates8 stated that the treatment with TB1 did not induce any significant degree of the drug resistance in the bacilli. Those reports cited above were the clinical investigations rather than they were a purely bacteriological analysis. In this connection, we attempted the detailed experiments of the sensitivity and resistance of tubercle bacilli to TB1 in vitro.