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@#Abstract: Objective To investigate the current status of streptomycin resistance of Yersinia pestis caused by point mutations of rpsL gene in Qinghai, so as to provide theoretical basis for precise clinical medication and prevention of drug resistance of human plague outbreak in South area of Qinghai Province in the future. Methods A total of 104 representative strains of Yersinia pestis collected from plague patients, vector insects and intermediate hosts in South area of Qinghai Province from 1957 to 2009 were screened, isolated and cultured by Hiss agar plates. The DNA of representative Yersinia pestis was extracted by sodium dodecyl sulfate lysis and phenol-chloroform method. The primers forward primer and reverse primer and TaqMan-MGB probes probe1 [FAM] and probe2 [VIC] were designed for the rpsL gene of streptomycin resistance gene in China. Real-time PCR with TaqMan-MGB fluorescent probe was used to detect the mutations of rpsL gene in streptomycin resistance locus of 104 strains of Yersinia pestis in South area of Qinghai Province. Results The FAM test results of 104 strains in South area of Qinghai Province were positive, corresponding to the detection of rpsL (128 : A ), RFU peak >1 000,negative <200. VIC test results of all tested strains were negative, corresponding to the detection of rpsL (128:G), RFU peak <200, positive >1 000. That is, no strains with rpsL gene mutation related to streptomycin resistance were found in the 104 strains of Yersinia pestis in Qingnan Province. Conclusion This study provides basic data on the distribution of streptomycin resistance of Yersinia pestis in South area of Qinghai Province, and lays a foundation for preventing the occurrence of drug resistance and clinical treatment of Yersinia pestis in South area of Qinghai Province.
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ObjectiveTo establish a novel rapid detection method based on PCR-single-strand-conformational polymorphism (PCR-SSCP) to determine mutation of streptomycin-resistance associated rpsL and rrs genes in isolates of Mycobacterium tuberculosis (MTB).MethodsStreptomycin-resistance of 112 MTB isolates was detected using the routine drug susceptibility test,and a special PCR-SSCP assay was established.The mutations of rpsL and rrs genes in streptomycin-resistant MTB isolates were detected by PCR-SSCP and PCR direct sequencing (PCR-DS) ; the results from two techniques were compared.Results All isolates had both rpsL and rrs genes.Fifty-two isolates (46.4％) were streptomycin susceptible,in which only 1 isolate showed abnormal PCR-SSCP fragments from rrs gene,and the specificity of PCR-SSCP was 98.1％ (51/52).Sixty isolates (53.6％) were streptomycin-resistant,in which 46 (76.6％) and 11 ( 18.3％ ) isolates presented the abnormal PCR-SSCP fragments of rpsL and rrs gene,respectively.One streptomycin-resistant isolate showed abnormal PCR-SSCP fragments from both rpsL and rrs genes.The sensitivity of PCR-SSCP was 93.3％ (56/60).ConclusionThe PCR-SSCP that established in this study is a specific and sensitive method for rapid detection of the streptomycin-resistance associated mutations in rpsL and rrs genes of MTB.
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OBJECTIVE To design molecular beacon probe of 43 Codon of high mutation site in rpsL of STR resistant MTB and its amplification system, meanwhile, to find the way of detecting the fluorescent light and making a qualitative judgment by use of fluorescence microscope and image analysis software. METHODS The software, Beacon designer, was used to design the 43 Codon molecular beacon probe and the amplification system, and the fluorescence microscope and image analysis software were used to detect the fluorescent light and make a qualitative judgment. RESULTS The strap of amplification product was shown clearly. The difference between PCR products from standard strain and STR resistant one was obvious in detecting the fluorescent light by use of fluorescence microscope. The rate of resistant STR detected was about 80% (P