title: Extensively drug-resistant tuberculosis: current challenges and threats.
abstract: Extensively drug-resistant tuberculosis (XDR-TB) is defined as tuberculosis caused by a Mycobacterium tuberculosis strain that is resistant to at least rifampicin and isoniazid among the first-line antitubercular drugs (multidrug-resistant tuberculosis; MDR-TB) in addition to resistance to any fluroquinolones and at least one of three injectable second-line drugs, namely amikacin, kanamycin and/or capreomycin. Recent studies have described XDR-TB strains from all continents. Worldwide prevalence of XDR-TB is estimated to be c. 6.6% in all the studied countries among multidrug-resistant M. tuberculosis strains. The emergence of XDR-TB strains is a reflection of poor tuberculosis management, and controlling its emergence constitutes an urgent global health reality and a challenge to tuberculosis control activities in all parts of the world, especially in developing countries and those lacking resources and as well as in countries with increasing prevalence of HIV/AIDS.
authors.affiliation: Department of Microbiology, C.S.M. Medical University, Lucknow, India. amita602002@yahoo.com
authors.forename: Amita
authors.initials: A
authors.lastname: Jain
authors.forename: Rajesh
authors.initials: R
authors.lastname: Mondal
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D003140:Communicable Disease Control; D024901:Drug Resistance, Multiple, Bacterial; D054908:Extensively Drug-Resistant Tuberculosis / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D015995:Prevalence
chemical_list: D000995:Antitubercular Agents