The prevalence of common mutations in rpsL gene associated with resistance to streptomycin in random and multiple drug resistant isolates of M. tuberculosis from Pakistan

Mutations in rpsl gene associated with resistance to streptomycin were screened in multiple drug resistant and randomly collected isolates of m. tuberculosis from pakistan. mutations were detected by pcr amplification of rpsl gene followed by dot-blot hybridization with allele-specific radioactivelylabeled probes and by pcr-rflp. out of 45 isolates,31 were resistant to streptomycin,while 14 were sensitive by conventional drug sensitivity assay. the rpsl43 mutation was found in 7 out of 31 isolates tested (22.58%) while rpsl88 was found in 4 out of 31(12.90%) isolates. the rpsl43 was also found in 27% isolates collected randomly,while rpsl88 was found in 5.4% isolates. all susceptible isolates had no mutation when probed with rpsl43 or rpsl88. the presence of rpsl43 mutation in randomly collected isolates indicates a high level of resistance to streptomycin. copyright 2014 zoological society of pakistan.