Amplification of Hsp 65 gene and usage of restriction endonuclease for identification of non tuberculous rapid grower mycobacterium.

BACKGROUND: The rapid grower mycobacteria have emerged as significant group of human pathogen amongst the Runyon group IV organisms that are capable of causing infection in both the healthy and immunocompromised hosts. Study aimed to identification of species amongst rapid grower non tuberculous mycobacterial isolates by polymerase chain reaction - restriction enzyme analysis (PRA). Analysis and comparison of results with standard biochemical tests.

METHODS: Rapid grower non tuberculous mycobacteria had been collected from liquid culture section during the study period. All isolates were identified by conventional biochemical tests. A 441bp fragment of hsp65 genes was amplified and digested by two restriction enzymes, BstEII and HaeIII. Digested products were analyzed using polyacrilamid gel electrophoresis (PAGE).

RESULTS: During study, 121 rapid grower mycobacterial isolates were subjected for species identification. Isolates were obtained from pulmonary samples (72) and extrapulmonary samples (49). In the PRA test 8 different types of rapid grower mycobacteria were identified after analyzing the fragments generated through restriction enzymes. Mycobacterium chelonae (57/121) was the most common isolate in pulmonary and extrapulmonary samples. Mycobacterium fortuitum (42), Mycobacterium abscessus (11), Mycobacterium immunogen (06), Mycobacterium peregrinum (02), Mycobacterium smegmatis (01), Mycobacterium wolinskyi (01), Mycobacterium goodii (01) were identified as other species of rapid grower non tuberculous mycobacteria.

CONCLUSION: PRA is a rapid and accurate system for the identification of species of non tuberculous mycobacteria. Results of PRA and biochemical tests are concordant up to 98%.