[Rapid identification of non tuberculous mycobacteria by restriction pattern analysis].
BACKGROUND
The frequency of diseases caused by non tuberculous mycobacteria has increased in the last years. Their clinical diagnosis is difficult, mainly in immunocompromised patients. The identification of these mycobacteria by traditional methods is based on phenotypic characteristics and the results are obtained two to four weeks after their isolation in primary cultures.


OBJECTIVE
To report a new identification method for non tuberculous mycobacteria.


METHODS
The restriction pattern analysis method was implemented. It is based on the amplification, using polymerase chain reaction (PCR), of a polymorphic region of 440 base pairs that codifies Hsp65 protein, followed by a digestion with BstE II and Hae III restriction enzymes. The results were compared with patterns established for each strain.


RESULTS
Sixty four strains of mycobacteria obtained from clinical samples and seven reference mycobacteria, were identified using the traditional methods and restriction pattern analysis. The latter method identified the same strain as the former in 87.5% of cases. In the remainder 12.5% of cases there was no agreement between both methods. In these, the sequencing of a fragment of a gene that codifies 16S ribosomal RNA, confirmed the correct identification by restriction patterns.


CONCLUSIONS
Restriction pattern analysis is a rapid identification method for non tuberculous mycobacterial strains.
Araya R
Pamela
P
Unidad de Desarrollo, Santiago, Chile.
Velasco R
Maritza
M
Fernández O
Jorge
J
D015373:Bacterial Typing Techniques / Q000592:standards*; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000032:analysis; D008969:Molecular Sequence Data; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis; D009170:Nontuberculous Mycobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D015183:Restriction Mapping / Q000592:standards*; D017423:Sequence Analysis, RNA
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D004262:DNA Restriction Enzymes