Rapid, simple, and culture-independent detection of rpsL codon 43 mutations that are highly predictive of streptomycin resistance in Mycobacterium tuberculosis

The substitution of codon 43 in the gene rpsL is the single most common mut ation found in streptomycin-resistant Mycobacterium tuberculosis. The chara cterization of this mutation has been hampered by the need for prior cultiv ation of the mycobacteria, the need for DNA sequencing, or both. in this re port we describe a simple and culture-independent technique to detect this mutation directly from sputum samples, requiring little more than a polymer ase chain reaction (PCR) machine and a simple agarose minigel. There is no need for labeled probes or DNA sequencing, in a preliminary test of feasibi lity, interpretable results were obtained from all of 16 smear-positive and 1 of 4 smear-negative, culture-positive samples. Two of two samples contai ning M. tuberculosis with rpsL codon 43 mutations were correctly identified .