Identification of mycobacteria species by molecular methods

Abstract

In this study, mycobacteria, which were previously identified as Mycobacterium tuberculosis complex (MTC), and mycobacteria other than tuberculosis (MOTT) with cord factor and the p-nitro-alpha-acetyl-amino-beta-hydroxypropiophenone (NAP) test were reanalysed using the polymerase chain reaction—restriction fragment length polymorphism (PCR-RFLP) analysis method in order to confirm the identification, and at the same time, species accepted as MOTT were identified. Although the results of the NAP test were obtained within 3-5 days, the PCR-RFLP results were obtained in 1 day. Ten species identified as MTC with the NAP test and cord factor were confirmed with the PCR-RFLP method. Fourteen species accepted as MOTT were identified as Mycobacterium species with the evaluation of the bands observed after the restriction of PCR product with the PCR-RFLP method. These were as follows: three species Mycobacterium intracellulare type I, two species Mycobacterium phlei, two species Mycobacterium kansasii, one species Mycobacterium fortuitum type I, one species Mycobacterium gordonae type I, one species Mycobacterium abscessus type I, one species Mycobacterium scrofulaceum, one species Mycobacterium szulgai type I, one species Mycobacterium avium type II, and one species Mycobacterium terrae. Hence, the results of both the cord factor and the NAP test were confirmed with the molecular method, and at the same time, mycobacteria species identification was made by determining the fastest, easiest, and the most accurate result-giving method. Because PCR-RFLP is a very rapid method that provides exact identification of mycobacteria species, it can be performed in routine procedures.