Detection of katG, inhA and ahpC gene mutation in clinical isolates of isoniazid-resistant Mycobacterium tuberculosis in Makassar City, South Sulawesi, Indonesia.

BACKGROUND

Tuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis (M. tuberculosis). The world is currently facing challenges due to the spread of anti-tuberculosis drug-resistant of M. tuberculosis. Isoniazid-resistant (INH), is one of the first-line anti-tuberculosis agents that has a high resistance case. This study used Multiplex allele-specific Polymerase Chain Reaction (MAS-PCR) to detect the most common mutations associated with isoniazid resistance on inhA, katG, and ahpC gene.

METHODS

This study used samples from clinical isolates of M. tuberculosis which had been tested for their antibiotic sensitivity of first-line anti-tuberculosis drugs. The DNA extraction process was carried out using the boiling method and then amplified with specific primers for inhA, katG, and ahpC genes using the MAS-PCR method. The results are then read on the electrophoretic gel with an interpretation of the mutation gene when the target gene DNA bands were absent according to the allele-specific fragments target.

RESULTS

A total of 200 isolates were tested in this study consisting of isoniazid-resistant and susceptible with the largest distribution of Multi-Drug Resistant (MDR) isolates with a total of 146 isolates (73%). The most significant gene mutation was on the ahpC gene in 61 isolates (30,5%) and the combination mutation of the katG + ahpC gene in 52 isolates (26%) with sensitivity and specificity of the test reaching 87% and 42% for the detection of INH-resistant.

CONCLUSION

Mutation on the ahpC gene has the highest percentage in this study. AhpC gene can be considered one of the essential genes to be tested for the cause of isoniazid-resistant. Using MAS-PCR for detecting gene mutation in isoniazid-resistant was simple and easy, it has the potential to be widely used as a rapid screening molecular test.