Values of diagnostic tests for the various species of spirochetes.

Bacteria of the Borrelia burgdorferi sensu lato complex, responsible for Lyme disease, are members of the spirochetes phylum. Diagnostic difficulties of Lyme disease are partly due to the characteristics of spirochetes as their culture is tedious or even impossible for some of them. We performed a literature review to assess the value of the various diagnostic tests of spirochetes infections of medical interest such as Lyme borreliosis, relapsing fever borreliae, syphilis, and leptospirosis. We were able to draw similarities between these four infections. Real-time PCR now plays an important role in the direct diagnosis of these infections. However, direct diagnosis remains difficult because of a persistent lack of sensitivity. Serological testing is therefore crucial in the diagnostic process. All currently available diagnostic tools are imperfect, with a potential risk of false positive and false negative results depending on the clinical context. Physicians should always take into consideration the clinical and epidemiological context when Lyme disease, relapsing fever borreliae, syphilis, and leptospirosis are suspected.