The optimal timing for nucleic acid amplification testing (NAAT) posttreatment for Trichomonas vaginalis has not been fully established. Testing too soon posttreatment may detect remnant nucleic acid that is not from viable organisms, falsely misclassifying person as infected. The purpose of this study was to examine how long T. vaginalis nucleic acid is detectable postmetronidazole (MTZ) treatment.
Women diagnosed with T. vaginalis treated with MTZ (2 g single-dose or 500 mg twice daily for 7 days multidose) self-collected a vaginal swab for NAAT at baseline and each week postcompletion of treatment through test of cure (TOC) at week 4, when a culture was also performed. Women who reported interim sexual exposure or who were culture positive at 4 weeks were excluded. Time to first negative NAAT was examined using Kaplan Meier analysis.
All women receiving multidose metronidazole were NAAT-negative by 21 days and those receiving single dose by 28 days postcompletion of treatment. Though over half (60.7%) of the cohort reinitiated sex during follow-up¸ all reported using condoms during sex or that they and their partner were treated before sex. Six (6.7%) of 89 had a positive NAAT following their first negative NAAT.
The optimal timing for T. vaginalis retesting after completion of treatment is 3 weeks for those receiving multidose MTZ and 4 weeks for those receiving single-dose, though sexual reexposure and false negatives should be considered.
Women with trichomoniasis who were culture negative at 4 weeks posttreatment -completion and denied follow-up sexual exposure were retested weekly by nucleic acid amplification testing. No detectable trichomonal rRNA was found posttreatment with metronidazole at 3 weeks for multidose and 4 weeks for single-dose.
From the *Department of Epidemiology, Tulane School of Public Health and Tropical Medicine, New Orleans, LA;
†Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL; and
‡Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA
Conflict of Interest: All investigators except B.vd.P. received a portion of their salary, via their institutions from the NIH/NIAID 1R01AI097080-01A1. P.K., C.G., M.C.C.-K., N.S., R.A.L. have no other disclosures.
S.N.T. has received research support from Becton-Dickinson, Hologic, Cepheid, Beckman-Coulter, Roche, ELITech, GlaxoSmithKline, Melinta and Entasis Consulting and peer educator honoraria, and advisory board honoraria from Hologic and GlaxoSmithKline. D.H.M. has served as a consultant for BioFire Diagnostics and GlaxoSmithKline. B.Vd.P. receives research support, honorarium or consulting fees from Abbott Molecular, Becton-Dickinson, BioFire Diagnostics, Hologic, Roche Molecular, Rheonix and SpeeDx. Christina Muzny has served as a consultant for Lupin Pharmaceuticals.
Sources of Funding: This research was supported by a grant from the National Institute of Health/National Institute of Allergy and Infectious Disease (NIH/NIAID) 1R01AI097080-01A1. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the NIH/NIAID.
Study data were collected and managed using REDCap electronic data capture tools hosted at Tulane University. REDCap (Research Electronic Data Capture) is a secure, web-based application designed to support data capture for research studies, providing (1) an intuitive interface for validated data entry; (2) audit trails for tracking data manipulation and export procedures; (3) automated export procedures for seamless data downloads to common statistical packages; and (4) procedures for importing data from external sources.
Correspondence: Patricia Kissinger, PhD, 1440 Canal St. 8318, New Orleans, LA 70112. E-mail: firstname.lastname@example.org.
Received for publication October 31, 2018, and accepted December 16, 2018.