Molecular Surveillance of Clinical Neisseria gonorrhoeae Isolates in Russia

Abstract

The choice of adequate methods for epidemiological purposes remains a challenging problem in Neisseria gonorrhoeae molecular monitoring. In this study, the collection of geographically unrelated gonococci (n ‫؍‬ 103) isolated in Russian clinics was comparably tested by (i) a traditional serotyping scheme, (ii) por typing, (iii) Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST), and (iv) multilocus sequence typing (MLST). It is shown that, according to sequencing data, a third of the strains carried new porB1 alleles, as well as tbpB ones, and more than half of the samples had new sequence types (STs) as determined by NG-MAST or MLST. The discriminatory power for each typing method was calculated by using the Hunter-Gaston discriminatory index, D. Commonly, modern nucleic acid-based typing methods (por typing, NG-MAST, and MLST) appeared to be more efficient than the classical serotyping scheme. While the traditional serotyping gave a D value of 0.82, the por typing, NG-MAST, and MLST approaches yielded D values of 0.97, 0.98, and 0.91, respectively. Each typing technique revealed the distribution of gonococci slightly correlated with their geographical sources. However, only the MLST method STs were highly associated with certain phenotypes. Although ST1594, ST1892, and ST6720 were typical for susceptible gonococci, ST1901 and ST6716 were undoubtedly associated with a multidrug-resistant phenotype. We conclude that every tested nucleic acid-based typing method is suitable for N. gonorrhoeae molecular surveillance. However, the MLST method seems to serve large-scale epidemiological purposes, whereas the NG-MAST and por typing approaches are more appropriate for the investigation of local outbreaks.

Review and International Recommendation of Methods for Typing Neisseria gonorrhoeae Isolates and Their Implications for Improved Knowledge of Gonococcal Epidemiology, Treatment, and Biology

“…In such cases, an analysis of the exact test and its costeffectiveness is warranted and should not be routine. Typing with different highly discriminatory genetic methods on the same N. gonorrhoeae strains generally displays similar levels of discrimination and relatively high congruence; however, there is rarely complete identity (9,19,24,49,51,54,58,65,69,71,73,82,83,96,104,115,121,125,135,153,172,174,176,178,180,182,184,186). This is not surprising since the different genetic targets of the typing methods follow divergent evolutionary pathways and consequently have different evolutionary histories.…”

“…porB sequence typing methods have been used to describe gonococcal populations in a region and to identify clusters of strains (24, 49, 54, 58, 65, 69, 71, 73, 81, 83, 84, 87, 115, 130, 135, 163, 172-175, 178, 180, 184, 186), to trace strain identity between sexual contacts (24,81,172,173,178,186), to investigate treatment failure (173), and to study population genetics (52, 130,131,137,146,163). porB sequencing can also be used to supplement other typing methods, including DNA sequence-based methods such as NG-MAST (see below), thereby increasing the ability to discriminate between isolates as required (49,58,69,73,83,87,115,172,174,178,180,182).…”

Using Crude Whole-Genome Assemblies of Neisseria gonorrhoeae as a Platform for Strain Analysis: Clonal Spread of Gonorrhea Infection in Saskatchewan, Canada

“…The unique genetic backgrounds of these two clonal complexes are likely associated with their temporal and spatial expansions. Molecular surveillance of clinical N. gonorrhoeae isolates in Russia during a 1-year period revealed a high clonality of gonococcal isolates in which four clonal complexes were identified with high prevalence rates (27). Our results suggest that the gonococcal clonal complexes found in Saskatchewan are characterized not only by a high prevalence rate but also by their profound temporal persistence, indicating that these highly successful clonal genotypes have likely acquired a biological fitness advantage over other gonococcal genotypes.…”

Proteomics of Neisseria gonorrhoeae: the treasure hunt for countermeasures against an old disease

“…The Broad Institute has recently released the whole genome sequences of 14 GC clinical isolates in collaboration with the Neisseria gonorrhoeae Group to facilitate research into pathogenesis and genetic determinants of disease states ( Neisseria gonorrhoeae Group Sequencing Project, Broad Institute of Harvard and MIT 1 ). Additionally, multilocus sequence typing (MLST), which characterizes isolates based on internal fragments of housekeeping gene alleles, has been used to cluster GC patient isolates based on phenotype ( Ilina et al, 2010 ). A database of MLST data for Neisseria species has been established 2 , further facilitating MLST identification and genotypic grouping of GC isolates.…”