Abstract:

Objective  To explore the application value of DNA micro-array method for quick detection of drug resistant genes of Mycobacterium tuberculosis (M.tuberculosis). Methods  DNA micro-array method was adopted to detect the M.tuberculosis in sputum samples of clinically suspicious TB patients. The wild genotypes and different mutant genotypes of promoters of three genes relevant to resistance of rifampicin (RFP) and isoniazid (INH), i.e. rpoB, katG, and inhA, were detected. BACTECTM MGIT 960 system was used to cultivate M.tuberculosis and the modified Roche proportion method was adopted to perform drug susceptibility for positive liquid cultures. Results  Among 174 positive liquid cultures, 15 of them were rpoB mutant genotype. The mutation frequency of locus 531 was the highest and mutation rate was 66.7%. Seventeen cultures were katG/inhA mutant genotype and 12 of them were single mutation of katG with the mutation rate of 70.6%. Compared with the results of 68 cultures detected by the modified Roche proportion method, the detection rate of DNA micro-array method for detecting RFP and INH resistance was more than 90%. Conclusion  DNA micro-array method can quickly and reliably detect the gene mutation of rpoB, katG, and inhA in most clinical samples of suspicious TB patients. This method can be used to detect clinical drug resistance and guide clinical medication and diagnosis.

Key words: DNA micro-array, Mycobacterium tuberculosis, drug resistance