Identification of mutations conferring streptomycin resistance in multidrug-resistant tuberculosis of China.

We investigated the spectrum and frequency of mutations in rpsL, rrs, and gidB among 140 multidrug-resistant tuberculosis (MDR-TB) clinical isolates from China. The association between mutations and different genotypes was also analyzed. Our data revealed that 65.7% of MDR-TB were resistant to streptomycin (STR), and 90.2% of STR-resistant isolates were Beijing strains. STR resistance was correlated with Beijing family (P=0.00). Compared with phenotypic data, detection of mutations for the combination of these 3 genes exhibited 94.6% sensitivity, 91.7% specificity, and 93.6% accuracy. The most common mutations in STR-resistant isolates were rpsL128, 262, and rrs514, of which rpsL128 showed association with Beijing lineage (P=0.00). A combination of these 3 mutations can serve as the reliable predictors for STR resistance, showing the sensitivity, specificity, and accuracy of 85.9%, 97.9%, and 90.0%, respectively. Furthermore, gidBA276C, not A615G, was Beijing lineage specific. These findings are useful to develop rapid molecular diagnostic methods for STR resistance in China.