False-positive Lyme serology can be caused by infection with which organism?

False-positive Lyme serology can be caused by infection with which organism?

• A. Borrelia burgdorferi
• B. Staphylococcus aureus
• C. Treponema pallidum
• D. Escherichia coli

Answer: (C)

Lyme serology detects antibodies against Borrelia burgdorferi, but antibodies from other infections can cross-react with Borrelia antigens used in the test. Treponema pallidum, the bacterium that causes syphilis, is a related spirochete with shared antigenic determinants, so infection with T. pallidum can trigger antibodies that bind Borrelia antigens and yield a false-positive Lyme result. In contrast, organisms like Staphylococcus aureus or Escherichia coli are not spirochetes and do not typically cause this cross-reactivity in Lyme assays.

Lyme serology detects antibodies against Borrelia burgdorferi, but antibodies from other infections can cross-react with Borrelia antigens used in the test. Treponema pallidum, the bacterium that causes syphilis, is a related spirochete with shared antigenic determinants, so infection with T. pallidum can trigger antibodies that bind Borrelia antigens and yield a false-positive Lyme result. In contrast, organisms like Staphylococcus aureus or Escherichia coli are not spirochetes and do not typically cause this cross-reactivity in Lyme assays.