Sexually transmitted coinfections in patients with a new episode of syphilis

Objectives Sexually transmitted infections (STIs) are a major public health problem with an increasing trend worldwide. Syphilis is often associated with other STIs. We measured the STI coinfection rate in a sample of patients presenting with syphilis. Methods In a prospective interventional study, patients attending the STI clinic in Brescia, Italy, with a new diagnosis of syphilis were systematically tested for Chlamydia trachomatis, Mycoplasma genitalium , and Neisseria gonorrhoeae at genital, anal, and oral sites using molecular methods. Serological markers for HIV, hepatitis B virus, and hepatitis A virus were also searched. Statistical methods were used to measure the association between STI coinfections and demographic, behavioral, and clinical variables. Results Among 101 patients with syphilis, a concomitant STI was identified in 31 (30.7%) for a total of 38 STIs: C. trachomatis (17-16.8%), M. genitalium (10-9.9%), and N. gonorrhoeae (9-8.9%). Two additional patients with positive hepatitis B surface antigen were detected. Age was the only independent variable statistically inversely associated with a higher chance of STIs coinfection. Conclusions In the study setting, screening patients with syphilis for other STIs allowed detection of STI coinfection in almost a third of the cases. Most associated coinfections were asymptomatic, providing further public health benefit.