Usefulness of Genotype MTBDRplus assay in acid-fast bacilli positive smear specimens in Almeria, Spain.

INTRODUCTION The urgent need for operational research evaluating test performance in a real-world setting has been highlighted. The purpose of this study was therefore to evaluate the performance of MTBDRplus assay. MATERIALS According to the reference method, of the 155 clinical specimens with valid results, 147 were susceptible to rifampicin (RIF) and isoniazid (INH), with 4 being multi-drug resistant (MDR) and 4 with isolated resistance to isoniazid (INH). RESULTS The results of the MTBDRplus assay were 100% concordant for the MDR and mono-resistant to INH specimens. However, the MTBDRplus assay showed a resistance pattern to RIF in one specimen which was classified as susceptible by the reference method. The majority of the specimens (118/75.6%) were also tested using the MTBDRplus method after culture on Lowenstein-Jensen media, showing 100% agreement with the results of the test directly from the specimens. An MTBDRplus test result was available within an average of 8 days. CONCLUSIONS Overall, MTBDR results showed excellent results when compared with the reference method and achieved a significant time-reduction.