Current status of some antituberculosis drugs and the development of new antituberculous agents with special reference to their in vitro and in vivo antimicrobial activities

Tuberculosis (TB) is a growing international health concern, since it is the leading infectious cause of death in the world today. In particular, the increasing prevalence of multidrug-resistant (MDR)-TB has greatly contributed to the increased difficulties in the control of TB. Because of the global health problems of TB, the increasing rate of MDR-TB and the high rate of a co-infection with HIV, the development of potent new anti-TB drugs without cross-resistance with known antimycobacterial agents is urgently needed. This article deals with the following areas. First, it briefly reviews some recent findings on the pharmacological status of fluoroquinolones and rifamycin derivatives. Second, it describes other types of new agents, such as oxazolidinones (linezolid, PNU-100480), nitroimidazoles (nitroimidazopyran PA-824, metronidazole), 2-pyridone, riminophenazines and diarylquinolines, which are being developed as anti-TB drugs. In addition, the future development of new antitubercular drugs is briefly discussed according to the potential pharmacological targets. New critical information on the whole genome of Mycobacterium tuberculosis (MTB) was recently elucidated and increasing knowledge on various mycobacterial virulence genes will promote the progression in the identification of genes that code for new drug targets. Using such findings on MTB genome, drug development using quantitative structure-activity relationship may be possible in the near future.