Relapse of secondary syphilis after benzathine penicillin G: molecular analysis.

BACKGROUND AND OBJECTIVES

It is difficult to distinguish between relapse and reinfection in patients who develop a second episode of syphilis after treatment.

GOAL

The goal of this study was to use molecular methods to distinguish between relapse and reinfection in a patient with recurrent secondary syphilis.

STUDY DESIGN

Treponema pallidum tprK sequences were amplified from cerebrospinal fluid (CSF), skin, and blood from the initial presentation and from blood from the second presentation. Neighbor-joining clustering analysis was performed for deduced tprK sequences from the case patient and for sequences derived from blood and CSF of a different patient with secondary syphilis.

RESULTS

The case patient's tprK sequences from both episodes of syphilis clustered together with a high degree of similarity.

CONCLUSION

Our patient likely relapsed despite treatment.