Analysis of rpsL and rrs mutations in Beijing and non-Beijing streptomycin-resistant Mycobacterium tuberculosis isolates from Singapore

The Beijing genotype of Mycobacterium tuberculosis has frequently been found to be associated with drug resistance. Mutation analysis of the genes encoding 16S rRNA ( rrs ) and ribosomal protein S12 ( rpsL ) revealed a high frequency (97/102; 95.1%) of alterations in streptomycin-resistant M. tuberculosis isolates from Singapore, with rpsL K43R being the most common rpsL mutation (82/92; 89%), which was significantly associated with Beijing strains compared to non-Beijing strains (odds ratio=10.88, 95% confidence interval=3.48–34.1). This is the first study to report the association of Beijing strains with the rpsL K43R mutation in STR-resistant M. tuberculosis isolates with de novo resistance, as determined by clustering analysis.