MICRO_042213_Chlamydia and Rickettsia Flashcards
What type of organism is chlamydia?
Obligate intracellular bacteria
What does chlamydia rely on the host for?
ATP
What are the 2 developmental stages of chlamydia?
Elementary bodies (EB) and Initital bodies (IB aka reticulate bodies (RB))
What is the difference between elementary bodies and the initial bodies of chlamydia?
ELEMENTARY BODIES (EB) - Small, non-multiplying form with a rigid bacteria-like cell wall. Infectious form - transmits from one cell/person to another. INITIAL BODIES: Larger, multiplying form that Lacks rigid wall; non-infectious form
What is the intracellular growth cycle of chlamydia?
1) EB induces host cell to phagocytose them, 2) Once inside the cell, the EB lose their cell wall, grow larger, and synthesize RNA to make Ibs, 3) IBs divide by binary fission; some of it is converted back to EB.
What are the 3 different types of chlamydia that is known to infect humans?
1) C. psittaci “parrot fever”, 2) C. pneumonia, 3) C. trachomatis
Of the 3 different types of chlamydia, which one has multiple serotypes?
C. trachomatis
How is C. Psittaci “parrot fever” transmitted?
it’s a natural parasite of birds; transmitted to humans via fecal matter
What does C. psittaci cause?
1) interstitial pneumonia - progressive scarring of lungs, 2) fever, 3) headache
How is C. pneumonia transmitted?
aerosol droplets
What does C. pneumonia cause?
causes atypical pneumonia or bronchitis, mostly in adults
What is unique about C. pneumonia’s pathology?
detected in atherosclerotic lesions; may play a role in coronary atherosclerosis
What are the 4 different serotypes of C. Trachomatis?
1) Serotype D-K 2) A, B, C, 3) L1, L2, L3
Which C. Trachomatis serotypes are more invasive?
Serotypes A, B, C, and L1, L2, L3
What does C. Trachomatis serotype D-K cause in ADULTS? How is it normally transmitted?
Nongonococcal urethritis, a common venereal disease transmitted via sexual contact
What are the symptoms that C. Trachomatis serotype D-K cause in adults?
Males/Females are normally ASYMPTOMATIC but both sexes can have more severe diseases involving the epididymis or fallopian tubes that can ultimately lead to sterility
What does C. Trachomatis serotype D-K cause in infants? How is it normally transmitted?
Inclusion Conjunctivitis and/or Infant Chlamydial Pneumonia. Transmitted via perinatal transmission (since the bacteria grows in the mother’s cervical cells).
What is infant chlamydial pneumonia?
caused by C. Trachomatis serotype D-K; is an extension of the ocular disease (inclusion conjunctivitis)
What does C. Trachomatis serotype A, B, C cause?
blindness - it is the leading cause of PREVENTABLE blindness
How is C. Trachomatis serotype A, B, C transmitted?
1) Mechanical (finger to the eye), 2) flies/poor hygiene (prevalent in tropical Africa and Asia)
What symptoms do C. Trachomatis serotype A, B, C cause?
chronic infection of conjunctiva, which can cause the eyelashes to grow inward, which can cause corneal scarring and blindness
What does C. Trachomatis serotype L1, L2, and L3 cause?
painless papule that progresses to a genital ulcerating vesicle and sometimes progress to a painful suppurating disease of regional lymph nodes
How is C. Trachomatis serotype A, B, C transmitted?
veneral disease - transmitted via sexual contact
How would you treat chlamydia?
Tetracycline and Azithromycin (antibiotics that can enter the cells)
How would you diagnose chlamydia?
Intraurethral or endocervical smears: test for specific serotypes (direct immunofluorescence to detect cytoplasmic inclusion bodies, PCR, seroassays)
In the serological tests, what’s the difference between the acute vs convalescent serum samples?
ACUTE: on-going symptoms, little or no antibody. CONVALESCENT: >5 d post symptoms, a lot of antibody produced
What is Rickettsia?
an intracellular pathogen that’s is normally parasites of arthropods (vector)
What does Rickettsia rely on the host for?
adapted to take up ATP, NAD, and other metabolites, but can make their own ATP
What is the typical life-cycle of Rickettsia?
1) induces host cell to phagocytose them, 2) multiplies via binary fission, 3) pathogens released via host cell lysis
How do you diagnose Rickettsia?
1) PCR, 2) Serological tests for specific antigens or antibody response, 3) immunohistologic detections
How do you treat Rickettsia?
Tetracycline and DTT (for lice control)
What are the different types of Rickettsia?
1) R. typhi, 2) R. rickettsii, 3) R. akari, 4) prowazekii (think TRAP)
What does rickettsia prowazekii cause?
primary epidemic typhus
How is rickettsia prowazekii transmitted?
human lice
What is the pathogenesis of rickettsia prowazekii?
replicates first in capillary endothelial cells and after ~10d there is an onset of fever and severe headache, followed by a rash 4-7d later