Analysis of salivary biomarkers and the oral microbiome/virome of patients diagnosed with syphilis

Abstract

A pre-exposure prophylaxis (PrEP) is indicated for populations vulnerable to human immunodeficiency virus (HIV) infection. In these groups, an increase in the incidence of sexually transmitted infections (STIs) is observed due to changes in sexual behavior after the initiation of antiretroviral therapy. Among these STIs, syphilis stands out as a significant public health problem worldwide. Immunoassays are certainly the most commonly used in clinical practice. They involve the detection of antibodies in samples of whole blood, serum, or plasma. These tests are subdivided into two classes, treponemal and non-treponemal. However, such tests present considerable limitations, both in diagnosis and patient monitoring. In this context, saliva is a biological fluid that allows the identification of various biomarkers and also microorganisms capable of infecting the body. Moreover, its collection method is accessible, fast, and minimally invasive. Therefore, the present study will evaluate whether saliva samples constitute an option for the molecular diagnosis and monitoring of syphilis in a population of patients diagnosed with the disease under PrEP usage, and in people living with HIV in the city of São Paulo. For this purpose, saliva and plasma will be evaluated by vibrational spectroscopy and their biochemical composition will be assessed in situ by Fourier-transform infrared absorption spectroscopy (FTIR). Cytokine levels will be determined using the multiplex methodology - high sensitivity human cytokine-plex - Millipore Luminex® (Millipore Corporation, Billerica, MA), and detection of T. pallidum DNA through real-time PCR. This study will also analyze the oral microbiome and virome, aiming to contribute to the development of effective approaches for managing these individuals in order to understand the dynamics of infection and the presence of other associated STIs.