Typical and atypical clinical profiles in syphilis patients: will genotyping of syphilis agents and patients help to explain symptom differences?

INTRODUCTION: Syphilis, caused by Treponema pallidum subsp. pallidum, is a chronic sexually transmitted infection resulting in a broad spectrum of clinical manifestations showing a rising incidence at the global level. A high proportion of syphilis patients have atypical manifestations that may complicate clinical recognition and lead to diagnostic uncertainty and delays in treatment, thereby increasing the risk of syphilis transmission.

AREAS COVERED: We performed bibliographical searches of online databases to provide an overview of the clinical profiles observed in patients with syphilis. We also reviewed published correlations between clinical symptomatology and genotypes of the T. pallidum and syphilis patients.

EXPERT OPINION: T. pallidum strains analyzed in vitro revealed differences in growth characteristics and clinical T. pallidum isolates showed differences in the epidemiological success of individual allelic profiles. In addition, genetic differences in the clinical isolates were found with respect to syphilis stage at the time of diagnosis, multiple primary lesions and other patient characteristics. Moreover, first examples of human genomic polymorphisms involved in syphilis susceptibility and progress of infection were discovered. These findings suggest that both genetic background of a treponemal strain and a patient contribute to the different clinical outcome of syphilis infection.