Fluoroquinolone-resistant Neisseria gonorrhoeae isolates from Russia: molecular mechanisms implicated.

During a longitudinal study of the prevalence of antimicrobial resistance in Neisseria gonorrhoeae, a number of high-level fluoroquinolone-resistant isolates were obtained from the sexually transmitted diseases clinic in the Moscow region in 2002. The aim of the present study was to determine the molecular mechanisms of resistance and to assess the clonal relationship of these strains For the 32 clinical strains of N. gonorrhoeae studied, the MIC values were determined for four fluoroquinolones. The gyrA, parC, por and mtrR genes were studied for the presence of mutations associated with fluoroquinolone resistance. We detected strains of N. gonorrhoeae showing high-level resistance to fluoroquinolones (21 strains, with MICs 1-32 mg/L). Mutations in gyrA and parC known to cause fluoroquinolone resistance were detected in a majority of strains. There were four strains (among 21) without known changes in gyrA and parC. However, amino acid changes in the Por protein and mutations in the promoter or encoding region of the mtrR gene were detected in three of them. One strain had no alteration in gyrA, parC, por or mtrR. The present study documents the first case of fluoroquinolone-resistant N. gonorrhoeae in Russia.