Phenotypic and Genotypic Characterization of Streptomycin-Resistant Multidrug-Resistant Clinical Isolates in Southern China.

Streptomycin (STR) is the first antibiotic used in the treatment of tuberculosis (TB) and the earliest antituberculosis drug with acquired resistance developed by The high prevalence of such resistance in many parts of the world limits its use for treating multidrug-resistant (MDR) TB. The aims of this study are to characterize of mutations in , , and genes in MDR isolates originating from southern China and to investigate possible relationship between mutations and strain genotypes for precise diagnosis and treatment. Sequences of , , and genes and the resistance profiles were analyzed for 218 MDR isolates. Our study showed that 68.35% of MDR isolates were resistant to STR and 89.91% of STR-resistant (STR) isolates were Beijing lineage strains. Mutations were observed in STR MDR isolates at the following rates: 72.48% in , 36.91% in , and 15.44% in . Compared with the phenotypic data, the combination of mutations in , , and has sensitivity and specificity of 96.64% and 100.00%, respectively. The most common mutations in STR isolates were 128,263 and 514,1401, of which 128 showed association with Beijing lineage ( < 0.001). It is noteworthy that a1401g mutation was present in , while MDR isolates were resistant to both STR and amikacin. Twenty two novel mutations were found in STR isolates. These findings could be helpful to develop rapid molecular diagnostic methods and understand STR resistance in China for developing TB precision medicine and disturbance of drug-resistant TB transmission.