[Emergence extensive drug resistance tuberculosis (XDR)].

Multi-drug resistant tuberculosis (MDR-Tb), caused by Mycobacterium tuberculosis, is long known, and it is defined to be resistant to both isonizid and rifampicin with or without resistance to other drugs. In addition to MDR-Tb, XDR-Tb (extensively drug-resistant tuberculosis) is resistant to any fluoroquinolone, and at least one of three injectable drugs, in addition to MDR-Tb. For some years these highly resistant Tb have been isolated world wide, which was named XDR 2006. Once no reliable therapy is available, the best way to prevent XDR-Tb is to ensure the efficacy of national TB control programs. The treatment must be in accordance with the results of drug susceptibility testing. Further, there is an urgent need to develop new Tb drugs. However, treatment is made difficult due to specific characteristics of Tb, e. g. the presences of metabolically silent, persistent or dormant bacteria within host lesions, which are not susceptible to antimycobacterial drugs, and its capability to rapidly develop drug resistance. This article informs about the current threat of the emerging XDR-Tb and summarizes possible options to curb with this phenomenon.