Rapid alternative methods for detection of rifampicin resistance in Mycobacterium tuberculosis

Objective: To study the performance of three rapid low cost methods for the detection of rifampicin resistance. Methods: A panel of 20 coded Mycobacterium tuberculosis strains was tested blindly by the low cost methods: nitrate reductase, MTT and resazurin assays, and compared with the results obtained with the gold standard methods: the proportion method on Lowenstein-Jensen medium and the BACTEC TB 460 system. We have also tested two commercial tests: MGIT and INNO LiPA Rif.TB kit. Results: Complete agreement was observed among all methods. Conclusion: These three simple methods might become inexpensive alternative procedures for rapid detection of rifampicin resistance in low-resource countries.