Characterization of Resistance Mutations Against First and Second Line Antituberculosis Drugs of Multi-Drug Resistant Mycobacterium tuberculosis Strains Isolated from Clinical Samples by in-House PCR Method and Comparison of Resistance Profiles

Abstract

Introduction: Multi-drug resistant tuberculosis (MDR-TB) is still an important public health problem. Rapid agent diagnosis and resistance status determination are critical in establishing the correct treatment protocol. This study was conducted to determine resistance mutations against first- and second-line antituberculous drugs in the MDR-MTB strain isolated from respiratory tract specimens. Materials and Methods: After subculturing the isolated Mycobacterium tuberculosis strains on the Löwenstein-Jensen medium, DNA isolation was carried out using the boiling method. DNA isolates were kept at -40 °C until the day of analysis. Primer sequences specific to rpoB, InhA, katG, gyrA, eis, and rrs regions were used to determine isoniazid, rifampicin, quinolone, and aminoglycoside resistance. Results: The positivity rate of rpoB, InhA, katG, gyrA, eis, and rrs in 33 MDR-TB isolates was 27 (81.8%), 31 (93.9%), 25 (75.7%), 25 (75.7%), 20 (60.6%) and 14 (42.4%), respectively. Resistance mutations were not detected in susceptible isolates. Conclusion: According to the data obtained from the study, it was found that fluoroquinolone resistance mutations were higher in isolates defined as MDR-TB by conventional and molecular methods, and the in-house PCR method was a useful method for rapid resistance detection.

Keywords

• mdr-tb
• mutation
• mycobacterium tuberculosis
• pcr