Assessing the
significance of the β-actin gene in tuberculosis diagnosis: an analytical study
utilizing anal fistula specimens
Paliwal Arjun, Gupta Sanjay, Dhingra GK, Kotiyal Shalini and Singh Ankita
Res. J. Biotech.; Vol. 20(2); 103-113;
doi: https://doi.org/10.25303/202rjbt01030113; (2025)
Abstract
Fistula samples from suspected tuberculosis (TB) patients play a crucial role in
diagnosing advanced extrapulmonary TB. This study examined 70 clinical specimens
of anal fistulae suspected of Mycobacterium tuberculosis (MTB) infection using both
conventional and molecular methods. The β-actin gene, a housekeeping gene, was assessed
for TB detection while microbiological profiling identified acid-fast bacilli. Molecular
profiling yielded positive results for both the IS6110 and β-actin genes in 14 samples,
suggesting MTB infection. In 13 samples, only the β-actin gene was positive, indicating
inflammation caused by other pathogens. Bayesian analysis was conducted to evaluate
the diagnostic performance of both gene tests.
The IS6110 gene test showed a sensitivity of 95% and specificity of 98% with a positive
predictive value (PPV) of 0.819 and a negative predictive value (NPV) of 0.993.
The β-actin gene test demonstrated a sensitivity of 90%, specificity of 99%, PPV
of 0.966 and NPV of 0.984. Bayesian calculations indicated a posterior probability
of 0.791 for TB in specimens positive for both genes. The findings emphasize the
β-actin gene as a potential marker for TB infection. Its detection in TB-negative
samples suggests the presence of alternative pathogenic microorganisms. This discovery
could be crucial for confirming diagnoses, particularly when radiol
