Identification of Mycobacterium species in direct respiratory specimens using reverse blot hybridisation assay

Abstract

Background: The early diagnosis of mycobacterial infections is a critical step for initiating treatment and curing the patient.

Objective: To evaluate the performance of the reverse blot hybridisation assay (REBA) Myco-ID for the rapid identification of Mycobacterium species in acid-fast bacilli (AFB) smear-positive respiratory specimens.

Design: A total of 148 AFB smear-positive respiratory specimens were used for the identification of Mycobacterium species using polymerase chain reaction (PCR) REBA, and the results were compared with the gold standard method as well as culture, PCR-restriction fragment length polymorphism analysis (PRA) and rpoB sequence analysis.

Results: The results of this assay showed that 59/148 samples were positive for M. tuberculosis and 87 were positive for non-tuberculous mycobacteria (NTM); one sample had mixed infection with both M. tuberculosis and NTM. One case was negative for both M. tuberculosis and NTM and was identified as Nocardia farcinica using PRA and sequence analysis. Of a total of 89 cases, the most frequently identified NTM species were M. intracellulare (n = 28, 31.5%), M. avium (n = 21, 23.6%), M. massiliense (n = 19, 21.3%) and M. abscessus (n = 16, 18.0%).

Conclusion: The PCR-REBA assay is an efficient tool for the rapid identification of the main Mycobacterium species in clinical specimens. The PCR-REBA assay can therefore provide useful information to physicians for appropriate treatment by clearly identifying Mycobacterium species.