TY - JOUR
T1 - Timing of primary syphilis treatment and impact on the development of treponemal antibodies
T2 - A cross-sectional clinic-based study
AU - Towns, Janet M.
AU - Leslie, David E.
AU - Denham, Ian
AU - Azzato, Francesca
AU - Karapanagiotidis, Theo
AU - Williamson, Deborah A.
AU - Graves, Stephen R.
AU - Fairley, Christopher K.
AU - Bissessor, Melanie
AU - Chow, Eric P.F.
AU - Zhang, Lei
AU - Chen, Marcus Y.
N1 - Publisher Copyright:
© 2022 BMJ Publishing Group. All rights reserved.
PY - 2022/5/1
Y1 - 2022/5/1
N2 - Background Serology is negative in a proportion of primary syphilis cases where Treponema pallidum PCR testing is positive. We aimed to identify discordant, T. pallidum PCR-positive, serology-negative primary syphilis cases and any clinical or laboratory factors associated with failure to subsequently seroconvert. Methods Serodiscordant primary syphilis cases that were T. pallidum PCR-positive and serology-negative (including rapid plasma reagin, T. pallidum particle agglutination, T. pallidum enzyme immunoassay or T. pallidum chemiluminescence assay) were identified from the Melbourne Sexual Health Centre electronic records between April 2011 and December 2019. Clinical and laboratory associations were examined. Results There were 814 primary syphilis cases in the study period and 38 (4.7%) were serodiscordant, 35 in men who have sex with men. Thirty-two had follow-up serology performed a median of 24 days later, of which 16 (50%) seroconverted, mostly (81%) within 6 weeks. Failure to seroconvert was significantly associated with treatment on day 1. Of the 12 cases treated on day 1, 10 (83%) failed to seroconvert compared with 6 of 20 (30%) among those who were treated after day 1. Discussion Earlier treatment of primary syphilis can prevent the development of serological markers. T. pallidum PCR can identify primary syphilis lesions before the development of serological markers and improve diagnosis of early primary syphilis lesions. Serology alone will miss a proportion of primary syphilis infections and should be repeated if a diagnosis of syphilis is being considered.
AB - Background Serology is negative in a proportion of primary syphilis cases where Treponema pallidum PCR testing is positive. We aimed to identify discordant, T. pallidum PCR-positive, serology-negative primary syphilis cases and any clinical or laboratory factors associated with failure to subsequently seroconvert. Methods Serodiscordant primary syphilis cases that were T. pallidum PCR-positive and serology-negative (including rapid plasma reagin, T. pallidum particle agglutination, T. pallidum enzyme immunoassay or T. pallidum chemiluminescence assay) were identified from the Melbourne Sexual Health Centre electronic records between April 2011 and December 2019. Clinical and laboratory associations were examined. Results There were 814 primary syphilis cases in the study period and 38 (4.7%) were serodiscordant, 35 in men who have sex with men. Thirty-two had follow-up serology performed a median of 24 days later, of which 16 (50%) seroconverted, mostly (81%) within 6 weeks. Failure to seroconvert was significantly associated with treatment on day 1. Of the 12 cases treated on day 1, 10 (83%) failed to seroconvert compared with 6 of 20 (30%) among those who were treated after day 1. Discussion Earlier treatment of primary syphilis can prevent the development of serological markers. T. pallidum PCR can identify primary syphilis lesions before the development of serological markers and improve diagnosis of early primary syphilis lesions. Serology alone will miss a proportion of primary syphilis infections and should be repeated if a diagnosis of syphilis is being considered.
KW - diagnosis
KW - PCR
KW - syphilis
UR - http://www.scopus.com/inward/record.url?scp=85103481765&partnerID=8YFLogxK
U2 - 10.1136/sextrans-2020-054739
DO - 10.1136/sextrans-2020-054739
M3 - Article
C2 - 33782149
AN - SCOPUS:85103481765
SN - 1368-4973
VL - 98
SP - 161
EP - 165
JO - Sexually Transmitted Infections
JF - Sexually Transmitted Infections
IS - 3
ER -