The roles of <i>rpsL</i>, <i>rrs</i>, and <i>gidB</i> mutations in predicting streptomycin-resistant drugs used on clinical <i>Mycobacterium tuberculosis</i> isolates from Hebei Province, China

Streptomycin (STR) is a component of first-line drugs used to treat multidrug-resistant tuberculosis. The purpose of this study was to investigate the proportion and type of mutations in Mycobacterium tuberculosis isolates resistant to STR and their relationship with the STR-resistant phenotype and with the epidemiological molecular model of the isolates. A total of 302 clinical isolates, including 215 STR-resistant and 87 STR-susceptible isolates, were characterized using the proportion method with Lowenstein-Jensen medium. The genes rpsL , rrs and gidB were screened for mutations using DNA sequencing methodology. All strains were genotyped using the spoligotyping technique. Mutations in rpsL and in rrs were observed in 63.3% and 15.8% of the STR-resistance isolates, respectively. The most prevalent mutations were the Lys43Arg substitution in the rpsL gene and the A514C change in the rrs gene. Ten novel mutations were identified in gidB . These novel mutations might be new potential markers for predicting STR-resistance in clinical Mycobacterium tuberculosis isolates. Mutations in rpsL , rrs , and gidB had a sensitivity of 84.2% and a specificity of 77.0% for the detection of STR-resistance isolates. The Beijing lineage strains were associated with the rpsL mutation Lys43Arg ( P = 0.051), as well as the dual gidB mutations Glu92Asp and Ala205Ala ( P rpsL and rrs can act as useful genetic markers for predicting STR-resistance, and gidB polymorphisms play an important role in STR-resistant clinical Mycobacterium tuberculosis isolates from Hebei, China.