Sung Ryul Kim

The Use of High Performance Liquid Chromatography to Speciate and Characterize the Epidemiology of Mycobacteria

OBJECTIVEnWe evaluated high-performance liquid chromatography (HPLC) for species identification of mycobacteria from various clinical specimens in an urban hospital in South Korea between January 2005 and December 2009.nnnMETHODSnIn the study period 24,774 cultures were completed, yielding the 3215 clinical isolates cultivated for mycobacteria and positive cultures that had mycolic acid investigated by HPLC. For species identification, we compared HPLC patterns of clinical isolates with 33 standard Mycobacterium species.nnnRESULTSnThere were 3 different HPLC groups with single, double, and triple-cluster patterns representing 9, 20, and 4 mycobacterial species, respectively. Species identification rates of HPLC for Mycobacterium tuberculosis and nontuberculous mycobacteria (NTM) were found to be 100% and 95.6%, respectively. Among mycobacterial isolates, 12.1% were NTM-positive. There were 20 different NTM species with frequencies of 0.3%~15.5%.nnnCONCLUSIONnThe HPLC method was highly sensitive identifying NTM isolated from clinical specimens.

The combination of real-time PCR and HPLC for the identification of non-tuberculous mycobacteria.

We used HPLC and AdvanSure real-time PCR (LG Life Sciences, Korea) to retrospectively analyze non-tuberculous mycobacteria (NTM) in 133 clinical specimens. The specimens were culture-positive for NTM and the HPLC method identified 130 strains of mycobacteria from the cultures (97.7%) at the species level. Among the isolates, 48 Mycobacterium. kansasii (36.1%), 39 M. intracellulare (29.3%), 17 M. avium (12.8%), 16 M. abscessus (12.0%), 6 M. fortuitum (4.5%), 2 M. szulgai (1.5%), 2 M. gordonae (1.5%), and 3 unclassified NTM strains (2.3%) were identified. The real-time PCR assay identified 60 NTM-positive specimens (45.1%), 65 negative specimens (48.9%), and 8 M. tuberculosis (TB)-positive specimens (6.0%). The real-time PCR assay is advantageous because of its rapid identification of NTM. However, in our study, the real-time PCR assay showed relatively low sensitivity (45.1%) when using direct specimens including sputum and bronchoalveolar lavage (BAL) fluid. HPLC is useful as it discriminates NTM at the species level, although it is time-consuming and requires specific equipment and technical expertise. A combination of both methods will be helpful for the rapid and accurate identification of mycobacteria in clinical laboratories.