Multiplex PCR as a novel method in the diagnosis of spinal tuberculosis-a pilot study

Establishment of a reliable and rapid diagnosis is of paramount importance in spinal tuberculosis. The available gadgetry of investigations, such as AFB smear, culture of Mycobacterium tuberculosis, and Uniplex PCR, suffers from a lack of adequate sensitivity and/or a lack of rapidity. Therefore, many times a diagnosis is made either very late in the disease process or sometimes empirical therapy has to be started because a definite diagnosis could not be made. All of these are not ideal situations for a clinician. The present study was done with the aim to establish a rapid and reliable diagnosis of M. tuberculosis infection. This was established by identifying M. tuberculosis genes.

The study was done on nine consecutive patients who presented with non-traumatic spontaneous vertebral compression collapse. CT-guided aspirate from the involved vertebra was subjected to Multiplex PCR (MPCR) using three primers: IS6110, protein b, and MPB 64. The aspirate was also subjected to smear and culture. The results of MPCR were compared with the final diagnosis.

Seven out of nine patients had a final diagnosis of tuberculosis. MPCR was positive in six of these seven patients, thus showing sensitivity of 85.7% and specificity of 100%. Results of MPCR were obtained within 24 h.

MPCR using IS6110, protein b, and MPB64 primers has a high sensitivity and specificity in rapid diagnosis of spinal tuberculosis. To the best of our knowledge, this has not been attempted before in spinal tuberculosis. This is particularly useful for paucibacillary infections like spinal tuberculosis. However, further studies using large sample sizes are needed to confirm the practical applicability of this technique.