[The rapid specific characterization of clinical isolates of the genus Mycobacterium by the polymerase chain reaction and restriction enzyme analysis].

BACKGROUND: Typing at species level of Mycobacterium is usually performed by microbiological and biochemical methods that require a long time and/or sufficient amount of bacteria. Molecular biology can avoid these problems using different techniques.

METHODS: A colony growth of the following mycobacteria has been analyzed: M. tuberculosis, M. kansasii, M. avium, M. intracellulare, M. gordonae, M. phlei, M. aurum, M. fortuitum, M. flavescens, M. marinum, M. xenopi, M. nonchromogenicum, M. terrae and M. chelonei. Strains were grown in Löwenstein-Jensen medium. DNA was obtained by proteolytic digestion and fenol extraction. The 16S rRNA gen was amplified by polymerase chain reaction (PCR) and the amplification was digested by HaeIII, HpaII, RsaI and AluI restriction enzymes. Restriction fragment patterns were analyzed by agarose gel electrophoresis and UV transillumination.

RESULTS: The combination of the patterns obtained with HpaII and RsaI was sufficient to generate 13 different combined ones. The patterns of M. intracellulare and M. avium were the same.

CONCLUSIONS: PCR and restriction enzyme analysis is an useful method for typing at species level of clinical isolates of mycobacteria.