Diagnosis of MDR-TB: a developing world problem on a developed world budget

The resurgence of tuberculosis worldwide has been accompanied by an increase in the incidence of multidrug-resistant tuberculosis on all continents. While significant advances have been made in the rapid and accurate diagnosis of Mycobacterium tuberculosis, the molecular biology methods used in the research laboratory to elucidate the mechanisms of drug resistance cannot be transferred to the centers delivering patient care. These methods require skilled operators, cumbersome protocols and extravagant expense. A number of companies that already have a large investment in M. tuberculosis diagnostics are adapting their high-throughput technology to drug susceptibility testing. These methodologies are not applicable to the developing world not only because of the costs involved but through a lack of infrastructure that is required to operate these machines and deliver specimens to the point of testing. Alternative technologies for drug susceptibility testing that do not rely on an investment in expensive hardware are presented and their potential use in the field is discussed. Though still relatively expensive to perform, these newer innovations may lead to the development of less intricate technologies that have universal application and begin to move away from our obsession with molecular-based diagnostics to produce on all encompassing gold standard.