Q.14 Which of the following are TRUE for Treponema pallidum?
P. It is the causative agent of syphilis
Q. It is a spirochete
R. It is a non-motile bacterium
S. It is generally susceptible to penicillin
Choose the correct combination.
(A) P, Q and R only (B) P, Q and S only (C) P, R and S only (D) Q, R and S only
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
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P: True. Treponema pallidum is the primary causative agent of syphilis, a sexually transmitted infection progressing through primary, secondary, latent, and tertiary stages.
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Q: True. This bacterium is classified as a spirochete, featuring a helical, spiral-shaped structure with endoflagella (axial filaments) enabling its characteristic corkscrew motility.
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R: False. Treponema pallidum is actively motile due to its endoflagella, allowing flexing, rotation, and translation; it is not non-motile.
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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
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Causative Agent of Syphilis (P: True): Triggers primary chancre, secondary rash, and potential tertiary complications like neurosyphilis if untreated.
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Spirochete Bacterium (Q: True): Possesses axial filaments for corkscrew motility, distinguishing it from non-spirochetes.
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Motile, Not Non-Motile (R: False): Actively moves via endoflagella, essential for tissue invasion.
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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.
