H.C.A. Zondag1, S.A. Nieuwenburg2, M. Himschoot1, M.F. Schim van der Loeff2,3,4, H.J.C. de Vries2,4,6, A.P. van Dam1,5, S.M. Bruisten1,4
1 Public Health Laboratory, Department of Infectious Diseases, Public Health Service Amsterdam, Amsterdam, the Netherlands
2 Department of Infectious Diseases, Public Health Service Amsterdam, Amsterdam, the Netherlands
3 Department of Internal medicine , Division of Infectious Diseases, Amsterdam UMC, Amsterdam, the Netherlands
4 Amsterdam Infection and Immunity Institute, Amsterdam UMC, University of Amsterdam, Amsterdam the Netherlands
5 Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam the Netherlands
6 Department of Dermatology, Amsterdam UMC, University of Amsterdam, Amsterdam the Netherlands
Background – Syphilis, caused by the bacterium Treponema pallidum subspecies pallidum (TPA), is a complex multi-stage sexually transmitted disease. Specific combinations of clinical manifestations and laboratory results allow the distinction between disease stages. Sexual transmission is known to occur in the primary, secondary and early latent stage. A study was set up to assess frequency of T. pallidum DNA detection in patients at various body locations and in different disease stages (TREPOLI study). The aim of the current project was to investigate the molecular variation between TPA isolates from different body locations within a patient and between patients in different syphilitic stages.
Method – Patients were recruited at the sexually transmitted infections (STI) clinic in Amsterdam. Eligible were men who have sex with men (MSM) diagnosed with primary, secondary or early latent syphilis. From all patients pharyngeal swabs, anal swabs, urine samples and peripheral blood samples were collected. From patients with ulcers (usually diagnosed with primary and occasionally with secondary stage syphilis) also ulcer swabs were obtained. TPA DNA was detected using an in-house PCR targeting the polA gene. Multilocus sequence typing (MLST) was performed by partial sequence analysis of the tp0136, tp0548 and tp0705 genes.
Results - From 232 patients included, 163 (70%) had at least one sample that tested PCR positive. Two or more positive samples were found in 89/232 (38%) patients. In addition, 80 ulcers linked to the included patients tested PCR positive. A total of 306 samples (80 ulcers, 63 anal swabs, 76 pharyngeal swabs, 26 peripheral blood samples and 61 urine samples) from were typed. So far, 61/306 (20%) samples were fully typed and 113/306 (37%) samples typed for at least one allele. The 61 fully typed samples consist of 22 ulcers, 7 anal swabs, 17 pharyngeal swabs and 15 urines. Seven distinct allelic profiles were found of which 1.3.1 (18/61; 30%), 1.1.1 (15/61; 25%) and 9.7.3 (15/61; 25%) were the most prevalent. Typing of the collection is on-going.
Conclusion and Discussion – Molecular typing of TPA samples obtained from additional anatomical locations besides the anogenital ulcer is challenging, due to low bacterial load in the samples, but feasible. Results of this study will contribute to the expansion of the public TPA sequence database and provide some insight in molecular characterization of the TPA bacteria during different syphilis stages and within patients. It will also show if the bacterium adapts genetically while dispersing through the body, during the on-going infectious stages.
34 IUSTI Congress - European Congres on Sexually transmitted Infections and HIV/AIDS
TAMING THE TIDE of STIs & HIV
Bucharest, September 3-5,