Molecular characterization of Treponema pallidum subsp. pallidum in Switzerland and France with a new multilocus sequence typing scheme

PLoS One. 2018 Jul 30;13(7):e0200773. doi: 10.1371/journal.pone.0200773. eCollection 2018.

Abstract

Syphilis is an important public health problem and an increasing incidence has been noted in recent years. Characterization of strain diversity through molecular data plays a critical role in the epidemiological understanding of this re-emergence. We here propose a new high-resolution multilocus sequence typing (MLST) scheme for Treponema pallidum subsp. pallidum (TPA). We analyzed 30 complete and draft TPA genomes obtained directly from clinical samples or from rabbit propagated strains to identify suitable typing loci and tested the new scheme on 120 clinical samples collected in Switzerland and France. Our analyses yielded three loci with high discriminatory power: TP0136, TP0548, and TP0705. Together with analysis of the 23S rRNA gene mutations for macrolide resistance, we propose these loci as MLST for TPA. Among clinical samples, 23 allelic profiles as well as a high percentage (80% samples) of macrolide resistance were revealed. The new MLST has higher discriminatory power compared to previous typing schemes, enabling distinction of TPA from other treponemal bacteria, distinction between the two main TPA clades (Nichols and SS14), and differentiation of strains within these clades.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Anti-Bacterial Agents / pharmacology
  • DNA, Bacterial / genetics
  • France / epidemiology
  • Genome, Bacterial
  • Genotype
  • Globus Pallidus
  • Macrolides / pharmacology
  • Multilocus Sequence Typing / methods*
  • Phylogeny
  • Polymorphism, Single Nucleotide
  • RNA, Ribosomal, 23S / genetics
  • Sequence Analysis, DNA / methods*
  • Switzerland / epidemiology
  • Syphilis / epidemiology
  • Treponema pallidum / genetics*

Substances

  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Macrolides
  • RNA, Ribosomal, 23S

Grant support

This work was supported by the University of Zurich, and the Grant Agency of the Czech Republic [GA17-25455S] to DS and [J17-25589Y] to MS, and by the Ministry of Health of the Czech Republic [17-31333A] to DS. Repsol Technology Center provided support in the form of salary for an author [HB], but did not have any additional role in the study choice, design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of authors are articulated in the ‘author contributions’ section.