Which organism causes syphilis?

Which organism causes syphilis?

• A. Treponema pallidum
• B. Neisseria gonorrhoeae
• C. Chlamydia trachomatis
• D. Haemophilus ducreyi

Answer: (A)

Syphilis is caused by a spirochete that is transmitted primarily through sexual contact and can affect multiple organ systems as it progresses. The organism responsible is Treponema pallidum. It is a slender, corkscrew-shaped bacterium that cannot be cultured with routine lab methods, so diagnosis relies on dark-field visualization in early lesions and on serologic testing (non-treponemal tests such as RPR or VDRL, followed by treponemal confirmation). Recognizing Treponema pallidum as the cause helps distinguish syphilis from other sexually transmitted infections caused by different bacteria—such as Neisseria gonorrhoeae (gonorrhea), Chlamydia trachomatis (chlamydia), and Haemophilus ducreyi (chancroid)—which have distinct etiologies and clinical courses.

Syphilis is caused by a spirochete that is transmitted primarily through sexual contact and can affect multiple organ systems as it progresses. The organism responsible is Treponema pallidum. It is a slender, corkscrew-shaped bacterium that cannot be cultured with routine lab methods, so diagnosis relies on dark-field visualization in early lesions and on serologic testing (non-treponemal tests such as RPR or VDRL, followed by treponemal confirmation). Recognizing Treponema pallidum as the cause helps distinguish syphilis from other sexually transmitted infections caused by different bacteria—such as Neisseria gonorrhoeae (gonorrhea), Chlamydia trachomatis (chlamydia), and Haemophilus ducreyi (chancroid)—which have distinct etiologies and clinical courses.