Detection of streptomycin resistance in Mycobacterium tuberculosis clinical isolates using four molecular methods in China.
To evaluate the relationship between mutations in rpsL or rrs genes and streptomycin (SM) resistance, we compared four molecular methods for their clinical value in the detection of SM resistance. Genotypic analysis of SM resistance in 167 M. tuberculosis clinical strains isolated from Chinese patients was performed by direct DNA sequencing, SSCP, RFLP, and reverse dot-blot hybridization (RDBH) assays. Of the 98 SM-resistant isolates, 78 (79.6%) had missense mutations in codon 43 or 88 of rpsL resulting in a Lys to Arg substitution, 6 (6.1%) had mutations of the rrs gene at positions 513 A to C or T or 516 C to T, and 14 (14.3%) had the wild-type sequence. None of the 69 SM-susceptible isolates examined had alterations in rpsL or rrs. The results of the SSCP, RFLP, and RDBH analyses for these mutations and wild-type sequences were completely consistent with DNA sequencing data. Five distinct single-nucleotide substitutions in codon 43 or 88 of rpsL gene or in position 513 or 516 of rrs gene were correctly identified in 84 of 98 (85.7%) phenotypically SM-resistant isolates by RDBH assay. Molecular analyses of the rpsL and rrs genes are useful for rapid prediction of SM resistance in most clinical strains of M. tuberculosis. Reverse dot-blot hybridization assay is a rapid, simple, and reliable method for the detection of drug resistance.
Wu
Xue-Qiong
XQ
Tuberculosis Research Laboratory, Tuberculosis Center the Second Affiliated Hospital, Chinese PLA General Hospital, Beijing 100091, China. wu-xueqiong@263.net
Lu
Yang
Y
Zhang
Jun-Xian
JX
Liang
Jian-Qin
JQ
Zhang
Guang-Yu
GY
Li
Hong-Min
HM
Lü
Cui-Huan
CH
Ding
Bei-Chuan
BC
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D002681:China; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D013307:Streptomycin / Q000494:pharmacology*
D000904:Antibiotics, Antitubercular; D013307:Streptomycin