Abstract: Objective To identify drug-resistant gene type in Mycobacterium tuberculosis isolates by PCR-oligonucleotide microchips,and to develop a new,rapid method for drug resistance.Method Using traditional drug susceptibility testing and PCR-DNA sequencing as control,katG,rpoB,rpsL,rrs,and embB genes from 157 M tuberculosis clinical isolates were analyzed by PCR-oligonucleotide microchip.Results The(katG,rpoB),rpsL,rrs,and embB genes from 36 drugsensitive M tuberculosis isolates analyzed were all wild-types.Of 121 drugresistant M tuberculosis isolates,56 isolates were resistant to INH,in which 62.5% had alterations in the katG,codon 315 is the most common site of gene mutation;94.2%(98/104) rifampicin-resistant isolates had rpoB gene mutations.Codon 531 and 526 of the rpoB are the most common sites of nucleotide substitutions, the mutations at codon 511,513,515,516,517,518 and 533 were also found.88.7% of 62 streptomycin-resistant isolates had mutations of the rpsL(82.3%) and rrs(6.5%) genes.There were mutations at codon 43,88 of the rpsL and position 513,516 of rrs.61.4% of 57 ethambutol-resistant isolates had nucleotide substitutions(ATG→GTG or ATA,ATC,ATT,CTG) at codon 306.The mutations found by gene chip were consistent with the Results of DNA sequencing.Conclusion The drug-resistant genetypes in the most drug-resistant Mycobacterium tuberculosis isolates could be identified with PCR-oligonucleotide microchip.

Key words: oligonucleotide microchip, drug-resistant genetype, PCR, Mycobacterium tuberculosis