Treponema Pallidum
Morphology
- Elongated, flexible
- Twisted spirally along the long axis
- Motile by endoflagella, which are polar flagella.
- Gram negative
- Discovered by Schaudinn and Hoffman
- The causative agent of syphilis
- Does not fulfill Koch’s postulate.
Staining
- Can not be seen under light microscope in wet films
- But wet films can be made out by negative staining with India ink.
- Pallidum does not take ordinary stains
- Stain light rose red with prolonged Giemsa staining.
- Morphology and motility can be seen under :
- the dark ground or phase contrast microscope.
- It can be stained by silver impregnation methods.
- Fontana’s method is useful for staining films.
- Levaditis’s method for tissue sections.
Cultivation
- Do not grow in artificial culture media.
- Obligate intracellular organism.
- Virulent strains can be maintained by serial testicular passage in rabbits eg. Nichol’s strain
- It is possible to maintain T. pallidum in motile and virulent form for 10-12 days in complex media under anaerobic conditions.
- Reiter strain (T phagedenis) –
- Non-pathogenic treponeme can grow in artificial culture.
Susceptibility
- Susceptibility of T. pallidum to heat was the basis of the fever therapy for syphilis.
- It is killed in 1-3 days at 0-4°C
- Transfusion syphilis can be prevented by:
- storing blood for at least four days in the refrigerator before transfusion.
Antibodies:
Reagin antibody:
- Responsible for Wassermann reaction, Kahn test, and VDRL.
- Hapten called cardiolipin is used as antigen.
- Chemically cardiolipin is diphosphatidyl glycerol.
Antibody to group antigen
- Found in both pathogenic and non-pathogenic treponemes.
Antibody to species-specific antigen
- Polysaccharide in nature
- Positive only with sera of patients infected with pathogenic treponemes
T pallidum has hyaluronidase:
- Breaks down the hyaluronic acid in the ground substance of tissue
- Enhances, invasiveness of the organism.
Exam Question
Morphology
- Motile by endoflagella, which are polar flagella.
- Discovered by Schaudinn and Hoffman
- The causative agent of syphilis
- Does not fulfil Koch’s postulate.
Staining
- Fontana’s method is useful for staining films.
Cultivation
- Do not grow in artificial culture media.
- Obligate intracellular organism.
- Reiter strain (T phagedenis) –
- Non-pathogenic treponeme, can grow in artificial culture.
Susceptibility
- It is killed in 1-3 days at 0-4°C
- Transfusion syphilis can be prevented by storing blood for at least four days in the refrigerator before transfusion.
Antibodies:
Reagin antibody:
- Responsible for Wasermann reaction, Kahn test, and VDRL.
Antibody to group antigen
Antibody to species-specific antigen
- T pallidum has hyaluronidase:
- Enhances, invasiveness of the organism.
Don’t Forget to Solve all the previous Year Question asked on Treponema Pallidum
