Multiple-locus variable number tandem repeat analysis of Neisseria gonorrhoeae isolates in Russia

In the present study, a multiple-locus variable number tandem repeat analysis (MLVA) was used to assess the molecular epidemiology of Neisseria gonorrhoeae clinical isolates originating from different regions of Russia. MLVA, based on seven loci, was performed on 218 isolates that were previously tested for susceptibility to penicillin, tetracycline and ciprofloxacin and for the presence of certain genetic determinants of drug resistance. In total, 83 MLVA types were identified, indicating that MLVA is a highly discriminatory technique with a Hunter-Gaston discriminatory index of 0.963 (95% CI, 0.950-0.977). MLVA type 16 was shown to be the most prevalent type and is undoubtedly associated with a multidrug resistant phenotype. The spread of MLVA type 16 from Moscow to Irkutsk suggests that this type has a highly successful transmission rate. Hierarchical cluster analysis of the MLVA profiles classified 208 isolates (95%) into six large groups (containing more than 10 isolates). Clusters differed in geographical characteristics and susceptibility profiles. MLVA cluster A comprised in total 34 isolates and was unambiguously associated with multidrug resistance. Most isolates in cluster A carried mutations in penA, ponA, rpsJ, mtrR, gyrA, and parC genes. MLVA cluster D was associated with resistance to penicillin and with mutations in ponA and rpsJ genes and the presence of plasmid-borne bla(TEM-1) gene. MLVA clusters B, C and E were associated with susceptibility to ciprofloxacin and had a lack of mutations in ponA, rpsJ, gyrA, and parC genes. We conclude that MLVA will be a useful tool for N. gonorrhoeae epidemiological studies.