Related Experiment Video
Updated: Feb 7, 2026

The MODS method for diagnosis of tuberculosis and multidrug resistant tuberculosis
Published on: August 11, 2008
Pyrosequencing: a rapid and effective sequencing method to diagnose drug-resistant tuberculosis
Aishwarya Govindaswamy1, Dhananjayan Sakthi2, Rekha Pai2
11Department of Clinical Microbiology, Christian Medical College, Vellore 632 004, India.
Purpose:
This study was undertaken to evaluate the efficiency of the pyrosequencing (PSQ) assay for the rapid detection of resistance to rifampicin (RIF), fluoroquinolones (FQs) and second-line injectables (SLIs) such as capreomycin (CAP) and kanamycin (KAN) in Mycobacterium tuberculosis (Mtb) clinical isolates.
Methodology:
Pyrosequencing is a simple and accurate short read DNA sequencing method for genome analysis. DNA extraction from Mtb clinical isolates was performed using Tris-HCl buffer and chloroform. The rpoB (RIF), gyrA (FQs) and rrs (aminoglycosides) genes were amplified, followed by sequencing using the PyroMark Q24 ID system. The PSQ results were compared with the results from the conventional drug susceptibility testing performed in the laboratory.
Results:
The sensitivity of the PSQ assay for the detection of resistance to RIF, FQ, CAP and KAN was 100 %, 100 %, 40 % and 50 %, respectively. The specificity of the PSQ assay was 100 %.
Conclusion:
The PSQ assay is a rapid and effective method for detecting drug resistance mutations from Mtb clinical isolates in a short period of time.
Related Concept Videos
Combined Effects of Drugs: Antagonism
The most common type is receptor antagonism, where one drug acts as an antagonist to block the effects of another drug by...
Antipsychotic Drugs: Therapeutic Uses and Side Effects
Despite these side effects, antipsychotics are used therapeutically for various purposes, including managing schizophrenia, preventing nausea and vomiting, curbing...
Combined Effects of Drugs: Synergism
Such synergistic combinations...
Diagnosing Acidosis and Alkalosis
First, the pH level is assessed to determine whether the blood pH is normal (7.35–7.45), low (acidosis), or high (alkalosis).
Next, the PCO2 and...
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a...
Therapeutic Drug Monitoring: Drug Analysis Methods

