PCR for Diagnosis of Tuberculosis
As we know, Tuberculosis is a highly infectious and contagious bacterial disease caused by
Mycobacterium tuberculosis. It spread from one person to another through tiny droplets which are released by an infected person into the air via a cough, spit, talk or sneezes and even small numbers of bacteria are enough to cause tuberculosis when inhaled. Tuberculosis affects the lungs but can also affect other parts of the body.
Pulmonary tuberculosis
Tuberculosis Peritonitis
Tuberculosis Pericarditis
Renal tuberculosis
Tuberculosis meningitis
Ocular infections
Lymphadenitis
Genital tuberculosis
Skeletal tuberculosis
General sign and symptoms of TB are chronic coughs, fever, weight loss, fatigue, loss of appetite and night sweats. Globally is two million people are infected with tuberculosis every year, of this about 40 % of the Indian population infected with TB. Therefore rapid and accurate detection of tuberculosis in patient’s specimens is very important for clinical use as well as public health.
The most commonly used methods for the diagnosis of tuberculosis are chest X-ray, AFB smear, Culture, and TB PCR. Although culture method is the gold standard it detects Mycobacterium tuberculosis in 3-4 weeks. PCR method is a highly sensitive assay and can provide results within a few hours. PCR assay detects Mycobacterium tuberculosis complex DNA (MTBC DNA) directly from pulmonary and extra-pulmonary samples.
Nucleic acid amplification techniques such as PCR are very useful in the rapid diagnosis of infection caused by Mycobacterium tuberculosis. Real-time PCR technology used for TB PCR is based on TaqMan Chemistry.
Mycobacterium tuberculosis DNA is extracted from samples, amplified using Real Time
Amplification and detected using fluorescent reporter dye probes specific for Tuberculosis
complex
PCR assay targets two specific genes – IS6110 and MPB64 which is present in members of M.
tuberculosis complex
In addition, the assay can also detect NTM is based on 16s gene
Detects inhibitors of PCR by addition of internal positive control which allows excluding
unreliable results
In addition, MDR TB PCR assay can detect genotypic rifampicin drug resistance/susceptible
status mediated by a mutation in the 81 bp region of rpoB target gene if present
TB PCR assay is a highly specific, sensitive, rapid and accurate test for the diagnosis of
tuberculosis
