Chlamydia, Rickettsia, And Friends Flashcards
What is the morphology of C.trachomatis?
Gram(-), but lacks peptidoglycan layer and muramic acid.
Where is C.trachomatis found?
Humans
How is C.trachomatis transmitted?
- Direct personal contact
2. Due to poor hygiene
What does C.trachomatis primarily affect?
- Eyes
- Genitals
- Lungs
What is the life cycle of C.trachomatis?
- Elementary body: dense spherule that infects cells.
2. Initial (reticulate) body: after EB enters the cell, it transforms into an initial body.
What is the metabolism of C.trachomatis?
- Larger and osmotically fragile
- Can reproduce via binary fission
- Requires ATP from the host
- The initial body transforms back into EB, which leaves the cell to infect other cells
What is important to keep in mind about Chlamydia?
They are obligate intracellular parasites - steal ATP from host with ATP/ADP translocator.
What is the virulence of C.trachomatis?
- Resistant to lysozyme (since their cell wall lacks muramic acid).
- Prevents phagosome-lysosome function.
- Non-motile
- No pili
- No exotoxin
What can serotypes A,B,C of C.trachomatis cause?
Trachoma: causes scarring of the inside of the eyelid, resulting in redirection of the eyelashes onto the corneal surface. This results in corneal scarring and blindness.
What do serotypes D through K of C.trachomatis cause?
- Ophthalmia neonatorum - inclusion conjunctivitis.
- Infant pneumonia
- Urethritis, cervicitis, PID (women)
- Non gonococcal urethritis, epididymitis and prostatitis (men)
What are the complications of chlamydial genital tract infections?
- Sterility, ectopic pregnancy and chronic pain may occur after PID.
- Reiter’s syndrome: triad of conjunctivitis, urethritis, and arthritis.
- Fitz-Hugh-Curtis syndrome - perihepatitis.
- Serotypes L1, L2, L3 –> Lymphogranuloma venereum.
Where is C.trachomatis “cultured”?
Can NOT grow on artificial media. Classically be grown in chick yolk sacs. Also, it is cultured in certain cell lines (McCoy lines).
How can we identify C.trachomatis in inclusion conjunctivitis (ophthalmia neonatorum)?
Scrapings from the surface of the conjunctiva will show intracytoplasmic inclusion bodies within conjunctival epithelial cells.
The inclusion bodies contain glycogen, and thus stain with iodine or giemsa.
How can we identify C.trachomatis in urethritis?
Most commonly diagnosed by PCR of urethral swab or urine sample.
How can we identify C.trachomatis in Lymphogranuloma venereum?
- Serologic tests
2. Frei test, which is rarely used, is similar to the PPD skin test for TB.
Where is Chlamydophila psittaci found?
Birds and poultry.
How is C.psittaci transmitted?
- Bird feces dry out.
2. Fecal particles are inhaled, infecting the lungs.
What is the life cycle of Chlamydophila psittaci?
Similar to C.trachomatis.
What is the virulence of C.psittaci?
Same as the one of C.trachomatis.
What can C.psittaci cause?
Psittacosis: viral-like atypical pneumonia , with fevere and dry, non-productive cough (similar to Mycoplasma pneumonia).
How can we identify C.psittaci?
- Serologically
2. Intracytoplasmic inclusion bodies do not stain with iodine
Where is Chlamydophila pneumoniae found?
Humans - spread from human to human.
How is C.pneumoniae transmitted?
Respiratory route
What is the life cycle of C.pneumoniae?
Similar to C.trachomatis.
What can C.pneumoniae cause?
Atypical pneumonia in young adults.