embB mutations in Mycobacterium tuberculosis ethambutol-resistant isolates / 中华检验医学杂志

ABSTRACT

Objectives To understand the mutations of embB genes in M. tuberculosis isolates, and to evaluate their clinical value. Method 102 clinical isolates were identified for their mycobacterial species, and then analyzed their embB genes with PCR SSCP, PCR RFLP, and PCR direct sequencing. Results Mycobacterium tuberculosis strain H 37 R v was used as a control. 102 clinical isolates all had the same 16S rDNA SSCP profiles as M. tuberculosis . Forty one drug sensitive isolates had normal embB SSCP and RFLP profiles. Of 61 ethambutol resistant isolates, 23 (37.7%) displayed abnormal embB SSCP profiles. Eight isolates had abnormal RFLP profiles. All embB mutations situated at codon 306, whose EMB MICs were more than 20 ?g/ml. Eight isolates had ATG to ATA or ATT mutations at codon 306. Thirty isolates had ATG to GTG or CTG mutations at codon 306, whose EMB MICs were more than 30 ?g/ml. Conclusions Ethabutol resistances in some M. tuberculosis isolates were due to mutations on embB genes. PCR SSCP and PCR RFLP method might become a simple and rapid diagnostic test for genotypes of M. tuberculosis ethabutol resistance.