Role of real-time PCR (RT-PCR) in rapid diagnosis of tuberculous mycobacteria in different clinical samples.
The study was aimed for molecular detection of mycobacterial DNA in different clinical samples using real-time polymerase chain reaction (RT-PCR) system and rapid diagnosis of tuberculosis. A total of 508 clinical specimens (blood 343, menstrual fluid 53, endometrial tissue 43, body fluid 36, pus from lymph nodes 18, sputum 8, urine 5 and semen 2) were included in this study. We extracted DNA using QIAamp DNA Mini Kit (QIAGEN, Germany) and performed real-time assay using Rotor-Gene Q machine from Corbett Research, Australia for specific amplification of IS6110 sequence of mycobacterial genome. The RT-PCR result was also compared with bacterial culture and acid-fast bacillus staining. RT-PCR assay showed positivity in 52 cases and negative in 456 cases. Corresponding positive results in culture and acid-fast bacillus staining methods were 49 cases and 24 cases respectively. The sensitivity and specificity of detecting Mycobacterium tuberculosis by RT-PCR were 93.87% and 98.69% respectively taking positive culture results as reference standards. The overall positive and negative predictive values were 88.46% and 99.34% respectively. RT-PCR is a useful diagnostic tool for rapid and sensitive detection of mycobacteria in different clinical samples. The easy processing, fast reporting and relative lack of contamination issues make it worthy as a possible replacement to time consuming culture techniques. Moreover, it has added advantage of quantification of mycobacterial DNA, hence bacterial load.
D000293:Adolescent; D000328:Adult; D000368:Aged; D012634:Bodily Secretions / Q000382:microbiology; D001826:Body Fluids / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*; D055815:Young Adult