Identificação molecular de Treponema pallidum

Abstract

Syphilis is caused by Treponema pallidum subspecies pallidum, a sexually transmitted infection (STI) with a broad spectrum of clinical manifestations, which varies according to the stages of infection and the host's immune status. Syphilis presents distinct symptomatic phases (primary, secondary and tertiary) and latency periods (recent and late latent syphilis), with acute and chronic lesions occurring to the disseminated form with neurological complications. Its diagnosis is based on clinical symptoms associated with serological tests. The molecular subtyping technique is a robust tool to investigate the diversity and epidemiology of T. pallidum. This study aimed to characterize T. pallidum isolated from a patient with primary syphilis using the Enhanced Centers for Disease Control and Prevention typing (ECDCT) method, this method consists of: 1) Determining the 60 bp number that repeats in the arp 2 gene ) RFLP (Polymorphism in Length of Restriction Fragments) of the subpramily II tpr genes (tpr EGJ); 3) Analysis of the 84 bp region of the tp0548 gene. Primary syphilis was diagnosed by combining clinical symptoms (presence of a painless lesion), with the rapid syphilis test (ABON Biopharm, Hangzhou, China) and the Venereal Disease Research Laboratory test (Abbott Murex, Dartford, UK). Treponemic DNA was identified in the lesion through the Polymerase Chain Reaction using the polA gene as a target, but it was not possible to identify T. pallidum DNA in the whole blood sample. The sequence of the arp gene fragment showed 14 repetitions, being reported as the most prevalent in the world. In the analysis of the tp0548 gene region, it was similar to subtype g, which is the most prevalent in some European countries. The isolated strain had a partial subtype 14 x / g. The PCR technique has been used as a sensitive and specific technique for the identification of T. pallidum DNA in clinical samples. The subtyping method demonstrates biological and clinical relevance in the investigation and discrimination of reinfections as well as in geographical identification.