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Volume 48, Number 2, April 2015

Rapid identification of Mycobacterium avium clinical isolates by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry 

Chuan-Sheng Lin, Chih-Cheng Su, Shang-Chen Hsieh, Chia-Chen Lu, Tsu-Lan Wu, Ju-Hsin Jia, Ting-Shu Wu, Chau-Chung Han, Wen-Cherng Tsai, Jang-Jih Lu, Hsin-Chih Lai

Received: February 6, 2013    Revised: August 7, 2013    Accepted: August 13, 2013   


Corresponding author:

Hsin-Chih Lai
Corresponding author. Graduate Institute of Medical Biotechnology and Laboratory Science, Chang-Gung University, 259 Wenhua 1st Road, Gueishan, Taoyuan 333, Taiwan. 


Background and purpose: 

Rapid and accurate discrimination of Mycobacterium avium from other mycobacteria is essential for appropriate therapeutic management and timely intervention for infection control. However, routine clinical identification methods for M. avium are both time consuming and labor intensive. In the present study, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to identify specific cellular protein pattern for rapid identification of M. avium isolates. 



A total of 40 clinically relevant Mycobacterium strains comprising 13 distinct species were enrolled for the MALDI-TOF MS identification. A 10-minute extraction-free examination procedure was set up to obtain mass spectral fingerprints from whole bacterial cells. 



The characteristic mass spectral peak patterns in the m/z (mass/charge ratio) range of 5–20 kDa can be obtained within 10 minutes. The species-specific mass spectra for M. avium is identified and can be differentiated from as Mycobacterium strains. This technique shortens and simplifies the identification procedure of MALDI-TOF MS and may further extend the mycobacterial MALDI-TOF MS database. 



Simplicity and rapidity of identification procedures make MALDI-TOF MS an attractive platform in routine identification of mycobacteria. MALDI-TOF MS is applicable for rapid discrimination of M. avium from other Mycobacterium species, and shows its potential for clinical application. 


Key words:

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, Mycobacterium avium, Rapid identification