Lebogang Kenaope1, Hannetjie Ferreira1, Faheem Seedat2, Kennedy Otwombe3, Neil A Martinson4, Ebrahim Variava5. 1. Department of Internal Medicine, Klerksdorp Tshepong Hospital Complex, North West Province Department of Health, University of the Witwatersrand, South Africa. 2. Department of Internal Medicine, Klerksdorp Tshepong Hospital Complex, North West Province Department of Health, University of the Witwatersrand, South Africa. Electronic address: faheem@global.co.za. 3. Perinatal HIV Research Unit (PHRU), MRC Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, South Africa. 4. Perinatal HIV Research Unit (PHRU), MRC Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, South Africa; Johns Hopkins University Center for TB Research, Baltimore, MD, USA. 5. Department of Internal Medicine, Klerksdorp Tshepong Hospital Complex, North West Province Department of Health, University of the Witwatersrand, South Africa; Perinatal HIV Research Unit (PHRU), MRC Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, South Africa.
Abstract
OBJECTIVE: Rifampicin-resistant (RR) tuberculosis (TB) on X-pert Mycobacterium tuberculosis/rifampicin (MTB/Rif) is assumed to be a surrogate for multi-drug resistant (MDR) TB. Following an RR result, a second specimen was taken for confirmatory culture and drug-susceptibility testing (DST). This study compared the initial diagnostic X-pert MTB/RIF result with the confirmatory DST in a high human immunodeficiency virus (HIV) seroprevalence setting. DESIGN: Records analysing demographics, HIV serostatus, prior TB treatments, and DST results were retrospectively reviewed. RESULTS: Of 604 patients with X-pert MTB/RIF RR, 374 (61.9%) had DST and were included. The mean age was 36.9 years and 82% were HIV infected. Following DST, MDR was confirmed in 49% and Rif mono-resistant (RMR) TB in 36%. Amongst RMR TB, 84% were HIV-infected, and amongst those with CD4 < 50 versus those 50-350 cells/mm3 RMR TB was noted in 51% versus 33%, respectively (P = 0.012). Primary DR was diagnosed in 43% (61% MDR and 33% RMR). CONCLUSION: Rifampicin resistance detected on a diagnostic X-pert MTB/Rif assay did not always predict MDR. Rifampicin mono-resistance is emerging amongst those with HIV co-infection and low CD4 counts (<50 cells/mm3). Research is needed to reduce the number of drugs and treatment durations for RMR TB.
OBJECTIVE:Rifampicin-resistant (RR) tuberculosis (TB) on X-pert Mycobacterium tuberculosis/rifampicin (MTB/Rif) is assumed to be a surrogate for multi-drug resistant (MDR) TB. Following an RR result, a second specimen was taken for confirmatory culture and drug-susceptibility testing (DST). This study compared the initial diagnostic X-pert MTB/RIF result with the confirmatory DST in a high human immunodeficiency virus (HIV) seroprevalence setting. DESIGN: Records analysing demographics, HIV serostatus, prior TB treatments, and DST results were retrospectively reviewed. RESULTS: Of 604 patients with X-pert MTB/RIF RR, 374 (61.9%) had DST and were included. The mean age was 36.9 years and 82% were HIV infected. Following DST, MDR was confirmed in 49% and Rif mono-resistant (RMR) TB in 36%. Amongst RMR TB, 84% were HIV-infected, and amongst those with CD4 < 50 versus those 50-350 cells/mm3 RMR TB was noted in 51% versus 33%, respectively (P = 0.012). Primary DR was diagnosed in 43% (61% MDR and 33% RMR). CONCLUSION:Rifampicin resistance detected on a diagnostic X-pert MTB/Rif assay did not always predict MDR. Rifampicin mono-resistance is emerging amongst those with HIV co-infection and low CD4 counts (<50 cells/mm3). Research is needed to reduce the number of drugs and treatment durations for RMR TB.