GENETIC ALTERATIONS IN STREPTOMYCIN-RESISTANT MYCOBACTERIUM-TUBERCULOSIS - MAPPING OF MUTATIONS CONFERRING RESISTANCE

We report on the identification of mutations associated with streptomy cin resistance in Mycobacterium tuberculosis. Two isolates (3656 and 3 976) showed a wild-type ribosomal protein, S12, but exhibited a single point mutation at 168 rRNA position 491 (C-->T) or 512 (C-->T), respe ctively. Sequence analysis of a third isolate (2438) revealed a single base change at 168 rRNA position 904 (A-->G). This position is equiva lent to invariant position 913 of the Escherichia coli 168 rRNA gene, an A-->G transition of which has been shown previously to impair strep tomycin binding and streptomycin-induced misreading in vitro. Surprisi ngly, strain 2438 harbors an additional mutation in the ribosomal prot ein S12 (Lys 88-->Gln).