Identification of Mycobacteria direstly in liquid media by PCR and restriction enzyme (PCR-REA) (Thai)

Abstract

PCR and restriction enzyme analysis (PCR-REA) based on 16S-23S rDNA spacer sequence was used
for detection and identification of mycobacteria in species level. The method was tested against 200 MGIT
positive samples. The sensitivity and specificity of the assay compared with culture results were 92.73 and
95.23%, respectively. The positive predictive value and negative predicted value were 99.40 and 60.60% 
respectively. Base on PCR-REA assay, these were classified into 161 slow growing mycobacteria and 5 rapid
growing mycobacteria. Among the 161 slow growers, 142 were identified as M. tuberculosis, five were M. avium,
one was M. intracellulare, three were M. kansasii /or gordonaer and ten were identified as slow growing mycobacteria. From the 5 rapid growers, two were identified as M. duvali, one was M. flavescens
and two were identified as rapid growing mycobacteria. The PCR-REA assay was easy to perform and could be
used for differential identification of mycobacteria directly in liquid media. Overall, PCR-REA assay for
mycobacteria should be used in combination with conventional methods and clinical findings for effective
diagnosis.