Is dark-field microscopy still useful for the primary syphilis diagnosis in the 21ST century?

Clara Lejarraga-Cañas; Oskar Ayerdi-Aguirrebengoa; Blanca Menéndez-Prieto; Estela Tello-Romero; Carmen Rodríguez-Martín; Jorge Del Romero-Guerrero

doi:10.1016/j.eimc.2020.09.005

Is dark-field microscopy still useful for the primary syphilis diagnosis in the 21^ST century?

Enferm Infecc Microbiol Clin (Engl Ed). 2020 Oct 22:S0213-005X(20)30295-0. doi: 10.1016/j.eimc.2020.09.005. Online ahead of print.

[Article in English, Spanish]

Authors

Clara Lejarraga-Cañas¹, Oskar Ayerdi-Aguirrebengoa², Blanca Menéndez-Prieto², Estela Tello-Romero², Carmen Rodríguez-Martín², Jorge Del Romero-Guerrero²

Affiliations

¹ Centro Sanitario Sandoval, Hospital Clínico San Carlos; IdISSC, Madrid, España. Electronic address: claralejarraga@gmail.com.
² Centro Sanitario Sandoval, Hospital Clínico San Carlos; IdISSC, Madrid, España.

PMID: 33268187
DOI: 10.1016/j.eimc.2020.09.005

Abstract

Introduction: Serological test for primary syphilis could be negative the first 5-15 days. The aim of this study was to evaluate the benefit of including dark field microscopy (DFM) in the diagnosis algorythm for primary syphilis.

Materials/methods: Patients attended to a sexual transmission diseases clinic of Madrid, from 2015 to 2019, for a genital ulcer with clinical suspicion of primary syphilis. They were tested for DMF and serological test (EIA/TPPA/RPR).

Results: Over the total amount of samples (806), 53.2% (429) were positive for DFM. Thus, the 48% of the 429 patients had negative serological test (EIA/RPR) of which the 77.6% were positive at TPPA.

Conclusions: DFM allows primary syphilis early diagnosis, even without serological test. If no direct detection methods are available, for patients without history of syphilis, TPPA could help to diagnose primary syphilis.

Keywords: Dark-field microscopy; Microscopia de campo oscuro; Primary syphilis; Syphilis diagnosis; Sífilis primaria; Sífilis/diagnóstico; Treponema pallidum.