Dr. Armand Van Deun and colleagues therefore gave a new application to a forgotten technique: vital staining with fluorescein diacetate (FDA). It only stains living TB bacilli, so doctors can immediately see those bacilli that are escaping treatment. The scientists improved the detection of the luminous bacilli by replacing the classical fluorescence microscope with its LED counterpart. Together with colleagues in Bangladesh, they tested the approach in the field for four years in a study made possible by a grant from the Damien Foundation.
Their approach appears to be much more efficient for poor countries. If, after treatment, the FDA-test were negative, in 95% of cases more elaborate tests didn’t find active bacilli in the patient’s sputum either. If the test were positive, the patient was identified as the carrier of a resistant bacillus.
A Simple, Less Costly, Fluorescein Test Allows for Correct Second Line Treatment of TB
This simple test allows the detection of a high number of resistant TB bacilli that otherwise would not have been discovered. The scientists report in the International Journal of Tuberculosis and Lung Disease that three times more patients could directly switch to the correct second-line treatment without losing time on a regimen ineffective against their resistant bacilli. This rediscovered technique can cut in half the number of cases where doctors start a retreatment, because it ascertains that the bacilli detected by the classical microscopy in fact are dead ones, which do not require further treatment.
The result? A more efficient treatment system, fewer deaths, and less spread of the disease. If this test is used consistently, it could be the turning point in the fight against TB around the world.
Van Deun, A., Maug, A. K. J., Hossain, A., Gumusboga, M., de Jong, B. C. Fluorescein diacetate vital staining allows earlier diagnosis of rifampicin-resistant tuberculosis. (2012). International Journal of Tuberculosis and Lung Disease. Accessed September 5, 2012.
United States Center for Disease Control and Prevention. Report on Tuberculosis. (2012). Accessed September 5, 2012.
World Health Organization. Report on Tuberculosis. (2012). Accessed September 5, 2012.