OBJECTIVE: To investigate the molecular mechanism of quinolone-resistance of M. tuberculosis and characterize the gene mutation in Sichuan Province. METHODS: Susceptibility of the clinical isolates to quinolones (ofloxacin, ciprofloxacin and sparfloxacin) was tested by the absolute concentration method. GyrA gene quinolone reasistance-determining region (QRDR) mutations M. tuberculosis were detected with PCR-SSCP and DNA sequencing. RESULTS: Of 68 clinical isolates of M. tuberculosis, 25 high-resistant, 11 low-resistant and 10 sensitive isolates were noted to have abnormal gyrA SSCP profile and different gyrA sequences from the standard strain H37Rv, and 14 sensitive and 8 low-resistant isolates were found with no mutation of gyrA gene. DNA sequencing unveiled Ser-->Thr mutation at codon 95, Asp-->Gly at codon 94, Ala-->Val at codon 90, and Ala-->Val at codon 83. CONCLUSION: This study confirmed the strong correlation between the quinolone-resistance and the mutation of gyrA gene, which might be a major molecular mechanism of quinolone-resistance in M. tuberculosis. The types of mutations exhibit no difference between Sichuan Province and other areas in China.
OBJECTIVE: To investigate the molecular mechanism of quinolone-resistance of M. tuberculosis and characterize the gene mutation in Sichuan Province. METHODS: Susceptibility of the clinical isolates to quinolones (ofloxacin, ciprofloxacin and sparfloxacin) was tested by the absolute concentration method. GyrA gene quinolone reasistance-determining region (QRDR) mutations M. tuberculosis were detected with PCR-SSCP and DNA sequencing. RESULTS: Of 68 clinical isolates of M. tuberculosis, 25 high-resistant, 11 low-resistant and 10 sensitive isolates were noted to have abnormal gyrA SSCP profile and different gyrA sequences from the standard strain H37Rv, and 14 sensitive and 8 low-resistant isolates were found with no mutation of gyrA gene. DNA sequencing unveiled Ser-->Thr mutation at codon 95, Asp-->Gly at codon 94, Ala-->Val at codon 90, and Ala-->Val at codon 83. CONCLUSION: This study confirmed the strong correlation between the quinolone-resistance and the mutation of gyrA gene, which might be a major molecular mechanism of quinolone-resistance in M. tuberculosis. The types of mutations exhibit no difference between Sichuan Province and other areas in China.
Authors: Sophia B Georghiou; Marisa Magana; Richard S Garfein; Donald G Catanzaro; Antonino Catanzaro; Timothy C Rodwell Journal: PLoS One Date: 2012-03-29 Impact factor: 3.240