[Relationship between streptomycin susceptibility and rpsL mutations of Mycobacterium tuberculosis strains].
The relationship between streptomycin (SM) susceptibility and rpsL mutations of Mycobacterium tuberculosis strains was studied. Of 18 clinically isolated SM-resistant M.tuberculosis strains, mutation was suspected in 9 strains (50%) with SM MICs of > or = 256 micrograms/ml by PCR-single strand conformation polymorphism targeting rpsL gene. On the other hand, using PCR-direct sequence method, amino acid substitution caused by single nucleotide point mutation in rpsL gene was demonstrated in 11 out of 18 strains (61%). The same amino acid substitution at codon 43 (Lys-->Arg) was observed in all 11 strains with SM MICs of > or = 256 micrograms/ml. In addition, PCR products obtained from these 11 strains could not be cut by a restriction enzyme, Mbo II, while H37Rv strain and the other 32 strains with SM MICs of < 256 micrograms/ml were cut into 2 fragments. In conclusion, our results suggest that highly SM-resistant M.tuberculosis strains with MICs of > or = 256 micrograms/ml could be rapidly and easily detected by the restriction enzymatic method.
Fukuda
M
M
Second Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Koga
H
H
Ohno
H
H
Ogawa
K
K
Yang
B
B
Miyamoto
J
J
Tomono
K
K
Kohno
S
S
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics*; D017354:Point Mutation; D013307:Streptomycin / Q000494:pharmacology*
D000904:Antibiotics, Antitubercular; D013307:Streptomycin