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Comparison Between Real-Time Polymerase Chain Reaction and DNA-Microarray in Detection and Identification of Mycobacterium Species

Author(s): Asaad Gaber, Hzem Hamed, Essam Elsawy

Low-cost and low-density (LCD) DNA arrays offer an easy way to detect resistance as minimal laboratory instrumentation is needed. Nucleic acid-based amplification tests allow the rapid detection of Mycobacterium tuberculosis. Recently, a real-time PCR assay for M. tuberculosis complex was introduced. Real-Time PCR and DNA-microarray techniques were compared with the classical methods of Ziehl-Neelsen (ZN) staining and culturing. Regarding to the standard culture method, 80 positive individuals were identified out of 140 urine samples. RT- PCR showed 96.3% sensitivity and 96.7% specificity with Mycobacterial tuberculosis complex (MTB) (n=10) and nontuberculous mycobacteria (NTM) (n=70). The DNA-microarray analysis exhibited 100% sensitivity and specificity. One species belonging to (MTB) was identified as M. tuberculosis and positively represented by 12.5% (n=10). Five species belonging to nontuberculous mycobacteria (NTM) were identified and represented as M. kansasii 37.5% (n=30), M. celatum 21.25% (n=17), M. gordonae 11.25% (n=9), M. chelonae 10% (n=8), and M. phlei 7.5% (n=6). The results recommend the use of our simple and rapid PCR technique for early diagnosis of mycobacteria’s. Also, the fast LCD-microarray protocol is very useful for species identification and differentiation between MTB and NTM