Future prospects for the MODS assay in multidrug-resistant tuberculosis diagnosis.

Extensively drug-resistant tuberculosis In 2004/2005, workers in Kwazulu-Natal, South Africa, became aware that some patients receiving effective antiretroviral therapy in their pioneering integrated HIV/tuberculosis (TB) program were dying despite undetectable HIV viral loads. Their subsequent detailed epidemiological study with enhanced surveillance for TB drug resistance finally blew the lid off an issue that has been smouldering unspoken for too long – that the era in which standardized, ‘best guess’, empirical TB therapy was an adequate blanket approach to TB control is over. Gerry Friedland and colleagues uncovered a previously unnoticed outbreak of extensively drug-resistant (XDR) TB [1], the current definition of which is the occurrence of TB in persons whose Mycobacterium tuberculosis isolates are resistant to isoniazid and rifampicin (thus all XDR is also multidrugresistant [MDR]) and also resistant to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin or capreomycin) [2].