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

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 Lwenstein-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.