Background Syphilis is resurgent among gay and bisexual men (GBM) despite effective treatment and widely available diagnostic serology. The polymerase chain reaction assay for Treponema pallidum (TP-PCR) is available, but little is known about the clinical features and outcomes for patients testing positive by TP-PCR.
Methods: Clinical data were collected from four medical practices for patients recording a positive TP-PCR result between 2004 and 2011. Demographic, serological, treatment and reinfection details were obtained. Results were stratified by HIV status and whether treatment conformed to international guidelines.
Results: 220 patients were positive for TP-PCR, of whom 92% were GBM. Seventeen (8.1%) were positive by TP-PCR before seroconversion. Almost one-third (32.1%) received treatment beyond that recommended in guidelines, and this was associated with HIV status (40.3% HIV positive vs 22.4% HIV negative, P<0.01). All but one patient with adequate follow up achieved serological cure. There was no significant difference in time to serological cure between the groups receiving standard therapy or enhanced therapy (95 vs 108 days; P=0.67) or between HIV positive and negative patients (93 vs 104 days, P=0.06). Nineteen patients were reinfected during follow up.
Conclusion: TP-PCR aids early diagnosis of syphilis and may be reactive before conventional serological tests. Treatment outcomes for TP-PCR-positive early infection were excellent, but a significant proportion of patients received non-standard therapy. Expanded use of syphilis PCR testing in at-risk populations is recommended since early identification and treatment is likely to be important in controlling the current epidemic in GBM.