Multicenter Study of TK Medium for Rapid Detection of M. Tuberculosis (Brazil and South Africa)
There is an urgent need for new tests to diagnose tuberculosis (TB), since existing tests have suboptimal performance characteristics or are too costly for implementation in low-resource settings. Global tuberculosis control would significantly benefit from the availability of a rapid, low-cost, culture system.
TK Medium is a rapid, solid-culture medium with multiple dye indicators that enable early detection of mycobacterial growth with the naked eye. The overall goal of this study is to conduct laboratory-based studies evaluating the performance of TK Medium for the diagnosis of pulmonary TB in the high-TB-incidence settings of Rio de Janeiro, Brazil, and Cape Town, South Africa. The primary objective is to evaluate the agreement between TK Medium and Lowenstein Jensen (LJ) Medium for detection of M. tuberculosis from respiratory specimens of pulmonary-TB suspects. Also evaluated will be the agreement between TK Medium and the Mycobacterial Growth Indicator Tube (MGIT) system; the mean time to positive growth for each medium; the contamination rates for each medium; the estimated costs for each medium; and the relative feasibility of implementation of the TK Medium method. This will be a prospective laboratory study of respiratory specimens submitted routinely to the clinical mycobacteriology laboratories at the study sites.
The focus of this activity is development and evaluation of a new tool for diagnosis of tuberculosis in settings located in developing/transitional countries with a high burden of TB. Results of this “early evaluation phase” study will guide decisions regarding subsequent larger-scale clinical evaluations of this promising new TB diagnostic method. This new tool has particular relevance for diagnosis of smear-negative TB, a significant challenge in populations with high rates of TB and HIV co-infection, such as South Africa. This new tool has promise as a cost-effective, more rapid alternative to LJ cultures and automated liquid-culture systems.