Analysis of Discordance between Genotypic and Phenotypic Assays for Rifampicin-Resistant Mycobacterium tuberculosis Isolated from Healthcare Facilities in Mthatha

The study sought to determine the rate of discordant results between genotypic and phenotypic tests for diagnosis drug-resistant tuberculosis (DR-TB). Sputum samples cultured isolates from suspected DR-TB patients were, respectively, analyzed Mycobacterium by Xpert® MTB/RIF (Cepheid, Sunnyvale, CA, USA) line probe assays (LPA) (Hain, Nehren, Germany). Discrepant rifampicin (RMP)-resistant were confirmed using BACTEC MGIT960 (BD, New York, NY, USA). Of 224 RMP-resistant obtained Xpert MTB/RIF, 5.4% susceptible RMP LPA. showed a 75% agreement with discrepancy was attributed either heteroresistance or DNA contamination during LPA testing in 58.3% cases. In 25% showing resistance MGIT960, laboratory errors causing false 16.7% cases, MTB/RIF. Out isolates, susceptibility isoniazid (INH) performed 73.7% which, 80.6% resistant. All 98.5% if TB resistant INH, but only 81.3% INH (p < 0.001). conclusion, should be considered when investigating results.