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.

Molecular characterization of Neisseria gonorrhoeae isolates in Almaty, Kazakhstan, by VNTR analysis, Opa-typing and NG-MAST.

In the present study, new variable number tandem repeats (VNTR) loci in the Neisseria gonorrhoeae genome were identified in silico. VNTR analysis scheme using PCR and agarose or polyacrylamide gel electrophoresis was developed based on nine VNTR loci with various degrees of polymorphism. The method was used to genotype a collection of 48 isolates, obtained from patients with gonorrhea in Almaty, Kazakhstan during the period from December 2008 to November 2009. This collection of isolates was also characterized by the opa-typing and multiantigen sequence typing (NG-MAST). The discriminatory power of the VNTR analysis translated by Hunter-Gaston Discrimination Index (HGDI) was similar to that of opa typing (HGDI=0.98 versus 0.97) and slightly higher than that of NG-MAST (HDGI=0.95). The adjusted Rand (AR) coefficients and Wallace coefficients showed that the overall concordance between the typing methods was not high. VNTR analysis described here is simple, inexpensive, easy to interpret, and it would be reliable for the comparison of data obtained in different laboratories. The proposed VNTR loci might be used for epidemiological studies of gonococcal infections.