Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link

Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.

Volume 32, Number 2—February 2026

Dispatch

Genomic Analysis of Doxycycline Resistance–Associated 16S rRNA Mutations in Treponema pallidum Subspecies pallidum

George S. Long, Mackenzie Neale, Thomas Braukmann, Vanessa Tran, Nishant Singh, Vanessa Allen, Muhammad Morshed, Jessica Minion, Paul Van Caeseele, Maud Vallée, Todd Hatchette, Samir N. Patel, Raymond S.W. Tsang, and Venkata R. DuvvuriComments to Author 
Author affiliation: Public Health Ontario, Toronto, Ontario, Canada (G.S. Long, T. Braukmann, V. Tran, N. Singh, V. Allen, S.N. Patel, V.R. Duvvuri); Public Health Agency of Canada, Winnipeg, Manitoba, Canada (M. Neale, R.S.W. Tsang); University of Toronto, Toronto (T. Braukmann, V. Tran, V. Allen, S.N. Patel, V.R. Duvvuri); Sinai Health and University Health Network, Toronto (V. Allen); British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada (M. Morshed); University of British Columbia, Vancouver (M. Morshed); Roy Romanow Provincial Laboratory, Regina, Saskatchewan, Canada (J. Minion); University of Saskatchewan, Regina (J. Minion); Cadham Provincial Laboratory, Winnipeg (P. Van Caeseele); University of Manitoba, Winnipeg (P. Van Caeseele); Laboratoire de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada (M. Vallée); Dalhousie University, Halifax, Nova Scotia, Canada (T. Hatchette); York University, Toronto (V.R. Duvvuri)

Main Article

Table 1

Demographic and genomic features of 17 Treponema pallidum samples from adults in Canada collected during 2016–2024 used in genomic analysis of doxycycline resistance–associated 16S rRNA mutations in T. pallidum subsp. pallidum*

Sample GenBank or BioSample accession no. Year Province Lineage
 Macrolide resistant
MLST PopPUNK
MB1 CP191228 2016 Manitoba SS14 SS14 Y
SK1 CP191227 2023 Saskatchewan SS14 SS14 Y
CDN1 SAMN49899419 2016 Manitoba SS14 SS14 Y
CDN2 SAMN49899420 2022 Manitoba SS14 SS14 Y
CDN3 SAMN49899421 2024 British Columbia SS14 SS14 Y
CDN4 SAMN49899422 2024 British Columbia Unknown SS14 Y
CDN5 SAMN49899423 2024 Saskatchewan SS14 SS14 Y
CDN6 SAMN49899424 2024 Saskatchewan SS14 SS14 Y
CDN7 SAMN49899425 2024 Saskatchewan SS14 SS14 Y
CDN8 SAMN49899426 2024 Saskatchewan SS14 SS14 N
CDN9 SAMN49899427 2024 Saskatchewan Unknown Nichols Y
CDN10 SAMN49899428 2024 Saskatchewan SS14 SS14 Y
CDN11 SAMN49899429 2024 Saskatchewan SS14 SS14 Y
CDN12 SAMN49899430 2024 Québec SS14 SS14 Y
CDN13 SAMN49899431 2024 Québec SS14 SS14 Y
CDN14 SAMN49899432 2024 Saskatchewan SS14 SS14 Y
CDN15 SAMN49899433 2024 Nova Scotia Nichols Nichols Y

*The TPA lineages were identified with both MLST and PopPUNK (14,15) (Appendix). Macrolide resistance was identified on the basis of single-nucleotide polymorphisms in the 23S rRNA gene (13). Samples were obtained from adults (18–64 years of age), apart from 2 (BC1 and BC2) that did not contain any identifying information.

Main Article

References
  1. Public Health Agency of Canada. Infectious syphilis and congenital syphilis in Canada, 2023 [cited 2025 Jun 23]. https://www.canada.ca/en/public-health/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2025-51/issue-2-3-february-march-2025/infectious-congenital-syphilis-2023.html
  2. Cato  K, Chuang  E, Connolly  KL, Deal  C, Hiltke  T. Summary of the National Institute of Allergy and Infectious Diseases workshop on alternative therapies to penicillin for the treatment of syphilis. Sex Transm Dis. 2025;52:201–10. DOIPubMedGoogle Scholar
  3. Hazra  A, McNulty  MC, Pyra  M, Pagkas-Bather  J, Gutierrez  JI, Pickett  J, et al. Filling in the gaps: updates on doxycycline prophylaxis for bacterial sexually transmitted infections. Clin Infect Dis. 2024:ciae062. DOIGoogle Scholar
  4. Dai  T, Qu  R, Liu  J, Zhou  P, Wang  Q. Efficacy of doxycycline in the treatment of syphilis. Antimicrob Agents Chemother. 2016;61:e01092–16. DOIPubMedGoogle Scholar
  5. Grossman  TH. Tetracycline antibiotics and resistance. Cold Spring Harb Perspect Med. 2016;6:a025387. DOIPubMedGoogle Scholar
  6. Dailidiene  D, Bertoli  MT, Miciuleviciene  J, Mukhopadhyay  AK, Dailide  G, Pascasio  MA, et al. Emergence of tetracycline resistance in Helicobacter pylori: multiple mutational changes in 16S ribosomal DNA and other genetic loci. Antimicrob Agents Chemother. 2002;46:3940–6. DOIPubMedGoogle Scholar
  7. Ross  JI, Eady  EA, Cove  JH, Cunliffe  WJ. 16S rRNA mutation associated with tetracycline resistance in a gram-positive bacterium. Antimicrob Agents Chemother. 1998;42:1702–5. DOIPubMedGoogle Scholar
  8. Yassin  A, Fredrick  K, Mankin  AS. Deleterious mutations in small subunit ribosomal RNA identify functional sites and potential targets for antibiotics. Proc Natl Acad Sci U S A. 2005;102:16620–5. DOIPubMedGoogle Scholar
  9. Stamm  LV. Global challenge of antibiotic-resistant Treponema pallidum. Antimicrob Agents Chemother. 2010;54:583–9. DOIPubMedGoogle Scholar
  10. Lieberman  NAP, Lin  MJ, Xie  H, Shrestha  L, Nguyen  T, Huang  ML, et al. Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar. PLoS Negl Trop Dis. 2021;15:e0010063.PubMedGoogle Scholar
  11. Tantalo  LC, Luetkemeyer  AF, Lieberman  NAP, Nunley  BE, Avendaño  C, Greninger  AL, et al. In vitro exposure of Treponema pallidum to subbactericidal doxycycline did not induce resistance: implications for doxycycline postexposure prophylaxis. J Infect Dis. 2025;231:729–33. DOIPubMedGoogle Scholar
  12. Manoharan-Basil  SS, Gestels  Z, Abdellati  S, de Block  T, Vanbaelen  T, De Baetselier  I, et al. Putative mutations associated with tetracycline resistance detected in Treponema spp.: an analysis of 4,355 Spirochaetales genomes. Access Microbiol. 2025;7:000963.v4.
  13. Stamm  LV, Bergen  HL. A point mutation associated with bacterial macrolide resistance is present in both 23S rRNA genes of an erythromycin-resistant Treponema pallidum clinical isolate. Antimicrob Agents Chemother. 2000;44:806–7. DOIPubMedGoogle Scholar
  14. Grillová  L, Bawa  T, Mikalová  L, Gayet-Ageron  A, Nieselt  K, Strouhal  M, et al. Molecular characterization of Treponema pallidum subsp. pallidum in Switzerland and France with a new multilocus sequence typing scheme. PLoS One. 2018;13:e0200773.PubMedGoogle Scholar
  15. Long  G, Singh  N, Patel  S, Braukmann  T, Tsang  RSW, Duvvuri  VR. Integrated genomic approaches improve Treponema pallidum phylogenetics and lineage classification. Can J Microbiol. 2025;71:1–11. DOIPubMedGoogle Scholar

Main Article

Page created: January 16, 2026
Page updated: February 09, 2026
Page reviewed: February 09, 2026
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external