Comparative evaluation of Polymerase Chain Reaction-Restriction Enzyme Analysis (PRA) and sequencing of heat shock protein 65 (hsp65) gene for identification of aquatic mycobacteria.

Traditional identification of mycobacteria based on cultural and biochemical tests can take several weeks and may fail to provide a precise identification. Polymerase Chain Reaction-Restriction Enzyme Analysis (PRA) of the gene encoding heat shock protein 65 kDa (hsp65) gene has been proposed as a rapid and inexpensive alternative approach. Despite being widely used for differentiation of mammalian mycobacteria, this method has only been applied in the identification of a small number of aquatic mycobacteria. The present study aimed to evaluate the potential use of PRA of hsp65 for the identification of aquatic mycobacteria compared with sequence analysis. Seventy one mycobacterial isolates including, 10 type/reference strains and the remainder field isolates, were subjected to PRA of a 441 bp fragment of this gene. For 68 representative isolates, sequence analysis was performed. All rapidly and slowly growing mycobacteria had best matches with 99.3% to 100% similarity with their corresponding species in the databanks. PRA proved to be a simple and rapid method for identifying aquatic mycobacteria. However, the incidence of similar or identical restriction patterns for some species of mycobacteria, and in particular, identification of new species of mycobacteria is a major problem using such a method. In contrast, the nucleic acid sequencing of the hsp65 gene yielded unambiguous results.