Identification of Mycobacterium species isolated from patients using high-performance liquid chromatography in Tehran during 2014-2015

Non-tuberculous mycobacteria (NTM) are defined as mycobacteria other than Mycobacterium tuberculosis (MTB), which do not cause tuberculosis or leprosy. Early and precise diagnosis of NTM is particularly important for the correct epidemiological control and specific treatments. The aim of this study was to identify the mycobacterium species isolated from patients referred to hospitals in Tehran using the high-performance liquid chromatography (HPLC) method.
In this cross-sectional descriptive study, a collection of isolates (n=20) was obtained from clinical specimens submitted to the Masoud Laboratory in Tehran, Iran, during 2014-2015. The strains were isolated from sputum, urine, blood, and various sterile body fluid specimens. Chromatography was conducted at a flow rate with a curvilinear gradient of methanol and methylene chloride, beginning at 98% methanol containing 2% methylene chloride and ending at 35% methanol contained in 65% methylene chloride.
From a total of 20 clinical isolates, 8 isolates (40%) were identified as Mycobacterium abscessus, 6 isolates (30%) M. tuberculosis, 3 isolates (15%) M. intracellulare and 3 isolates (15%) M. fortuitum.
For the proper treatment, rapid differentiation between MTB and NTM should be performed in persons who are diagnosed with or are suspected of having infectious TB disease. So, the HPLC method can be suggested as a cost-effective, specific and reliable method for rapid identification of MTB and differentiation of NTM strain from positive cultures isolated from clinical specimens.