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A complex method for detection of genetic markers of N. gonorrhoeae resistance to penicillin was developed. Mutations in penA and ponA genes were detected by minisequencing reaction with subsequent detection of reaction products by MALDI-TOF mass spectrometry. This approach was tested on 31 clinical strains of N. gonorrhoeae with minimum inhibitory concentration of penicillin from 0.03 to 8 microg/ml and higher. Mutations in penA and ponA genes in moderately resistant strains were shown (minimum inhibitory concentration up to 0.5 microg/ml) and mutations in penA, ponA, and penB genes in resistant strains (minimum inhibitory concentration more than 1.0 microg/ml). beta-Lactamase genes were detected in 4 strains with high resistance (minimum inhibitory concentration 4-8 and more microg/ml). Correlation between microbiological resistance and presence of respective mutations in the studied locuses was detected.

For many known mechanisms of the drug resistance in microorganisms are described genetic markers (specific changes in the genome of microorganism, in the majority of the cases representing single nucleotide polymorphism). The search for the new methods, which make possible to identify single nucleotide changes with the greater effectiveness and at smaller prime is actual for the solution of the problem of the identification of the resistant strains. In this work a new approach of the determination of single nucleotide polymorphisms is proposed. It is based on the reactions of mini-sequencing and/or sequencing with the subsequent Matrix-Assisted Laser Desorption/Ionisation Time Of Flight Mass-Spectrometry (MALDI-TOF MS) of the reaction products. The approach was tested on a clinical group of Neisseria gonorrhoeae strains to investigate specific single nucleotide polymorphisms in genes gyrA and parC (the genetic markers of the bacterium fluoroquinolone resistance). The results of the nucleotide polymorphism deter- mination was completely agreed with the data, obtained earlier with the use of a "gold standard" (sequencing with the classical gel-electrophoresis separation of the reaction products). There is specific interest in the method of sequencing of the short DNA sequences using MALDI-TOF MS. The new high-throughput approach of the single nucleotide polymorphisms determination in bacterial genes considerably increases the effectiveness of the methods of microorganism's identification, genotyping and determining the genetic markers of the drug resistance.

Fluoroquinolones still belong to the drugs of choice in the treatment of uncomplicated gonorrhea. At the same time, there have been more data on the spreading N. gonorrhoeae strains resistant to fluoroquinolones. A variety of mechanisms, like modification of the target of antibiotic's action (point mutations in genes gyrA and parC), a decreasing permeability of the bacterial cell membrane (amino-acid changes Por protein) and a growing efflux of antibiotic (mutations in the promoter or in the coding region of mtrR) mediate in the shaping resistance of the drugs. The MIC values for four fluoroquinolone-series antibiotics were determined and the gyrA, parC, por and mtrR genes were examined for resistance-responsible mutations in 32 studied clinical strains of N. gonorrhoeae. Strains with high resistance to fluoroquinolones were detected; 3 of them had no common changes in GyrA or ParC, however, amino acid changes and mutations were detected in Por protein and promoter or gene mtrR encoding region, respectively. The paper contains priority data on the detection (in Russia) of N. gonorrhoeae strains with high resistance to fluoroquinolones. Involvement of different mechanisms in the process of resistance shaping is discussed. The results are of practical importance for planning the antibacterial therapy of gonorrhoeae; they point out the need in regional testing of resistance in the N. gonorrhoeae population encountered in Russia.

Objectives: 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, Methods: 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., Results: 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., Conclusions: The present study documents the first case of fluoroquinolone-resistant N. gonorrhoeae in Russia.

Genetic polymorphism of Russian population of N. gonorrhoeae was detected and a system for genotyping of its clinical strains was introduced into practice. Comparative analysis of the prevalence of N. gonorrhoeae genotypes in Russia and abroad was carried out. For adaptation of the methods of molecular typing of N. gonorrhoeae strains and its approbation on clinical strains isolated in Russia 41 clinical strains of N. gonorrhoeae were typed. The predominance of PIB serovar (83%) was demonstrated.

The results of multicenter, randomized, double-blind comparative study of linezolid and vancomycin efficacy, safety and tolerability in the treatment of nosocomial pneumonia are presented. The trial was performed on 69 patients. Clinical efficacy of linezolid was 83 per cent, of vancomycin--79 per cent. Bacteriological effect (pathogen eradication) was 83 per cent for linezolid group and 86 per cent for vancomycin group. During the study good clinical tolerability of linezolid was demonstrated along with lower side effects incidence and shortened recovery period when compared to vancomycin.