Treponema pallidum causes syphilis and belongs to the spirochete group of bacteria, but it is motile, not non-motile. The correct combination of true statements is P, Q, and S.

Option Analysis

• P: True. Treponema pallidum is the primary causative agent of syphilis, a sexually transmitted infection progressing through primary, secondary, latent, and tertiary stages.​

• Q: True. This bacterium is classified as a spirochete, featuring a helical, spiral-shaped structure with endoflagella (axial filaments) enabling its characteristic corkscrew motility.​

• R: False. Treponema pallidum is actively motile due to its endoflagella, allowing flexing, rotation, and translation; it is not non-motile.​

• S: True. The bacterium remains generally susceptible to penicillin, which is the standard treatment of choice, administered as benzathine penicillin G for most stages.​

Correct Choice

Option (B) P, Q and S only matches the true statements, as confirmed in standard microbiology references and exam contexts like GATE BT.​

Treponema pallidum, the Treponema pallidum spirochete syphilis causative agent, is a thin, helical bacterium responsible for syphilis, a multi-stage sexually transmitted disease. This obligate parasite cannot be cultured on artificial media but is visualized via dark-field microscopy. Understanding its motile nature and penicillin susceptibility is crucial for medical students and researchers.

Key Characteristics

• Causative Agent of Syphilis (P: True): Triggers primary chancre, secondary rash, and potential tertiary complications like neurosyphilis if untreated.​

• Spirochete Bacterium (Q: True): Possesses axial filaments for corkscrew motility, distinguishing it from non-spirochetes.​

• Motile, Not Non-Motile (R: False): Actively moves via endoflagella, essential for tissue invasion.​

• Penicillin Susceptible (S: True): Responds well to penicillin G, with no widespread resistance reported.​

Clinical Relevance

Syphilis diagnosis relies on serological tests (e.g., VDRL, TPHA) alongside direct observation. Treatment halts progression, emphasizing early detection. For exams, note that options excluding the false “non-motile” claim, like P, Q, S, are correct.​