[Analysis of point mutations in the ygeD, gyrA and parC genes in fluoroquinolones resistant clinical isolates of Chlamydia trachomatis].

Resistance of 14 clinical isolates of C. trachomatis to fluoroquinolones, i.e. of ciprofloxacin, pefloxaxin and ofloxacin, was assayed. Three isolates with a high resistance degree to all 3 drugs (MIC equal or above 64 microg/ml) were detected. MIC was found to be equal to or below 4 microg/ml for 3 isolates. The remaining isolates had an intermediate resistance level. The nucleotide sequence was established for the Quinolone-Resistance Determining Region (QRDR) genes coding the DNA-gyrase subunit A (gyrA) and DNA-topoisomerase IV subunit C (parC) as well as for the 3'-region of ygeD coding, presumably, the efflux protein. In none of the isolates, the gyrA and gyrC QRDR differed from the corresponding regions in the published C. trachomatis genome sequence. Several silent mutations and mutations resulting in amino acid substitutions were observed in the ygeD 3' region of 2 isolates resistant to high FQ concentrations and in 1 isolate with the intermediate resistance level.