Chylamidia Flashcards
What are the 3 types of Chlamydiae discussed?
C. trachomatis
Chlamydophila psittaci
Chalmydophila pneumoniae
List the important properties of Chlamydiae
- Obligate intracellular pathogens
- non-motile, gram -
- contain DNA and RNA
- can withstand PNC and Cephs, but susceptible to others
- cell wall lacks peptidoglycan, has LPS
What is the life cycle?
- Spore (elementary body) infects host
- ingested into macrophages/lymphocytes
- in cell, turns into reticulate body (active)
- multiplies via binary fission
what is the inclusion membrane?
used to distinguish between trachomatis (has peptidoglycan) and psittaci/pneumonia (no glycogen)
What does each species of Chlamydia Cause?
C. trachomatis (A-C) causes trachoma, endemic blining
C. trachomatis (D-K) causes stds (urethritis, cervicits, neonatal pneumonia via birth, conjunctivitis via birth)
C. trachomatis (l1-L3) causes Stds
C. psittaci cuases psittacosis
C. pneumoniae causes atypicial “walking” pneumonia
How is C. trachomatis (A-C) spread?
Resevoir?
Sympotoms?
how to diagnose;
Where does it occur?
Caused by Chlamydia trachomatis (A-C)
Spread via fingers/touch, fomites, and flies
Humans only
keratoconjunctivits, corneal pannus
miscroscopic exam - look for inclusion bodies
Occurs in hot, dry enviro (N. Africa/ asia)
What co-infects w/ Chlamydia trach?
Neiserria
What are the 4 stages of Trachoma?
- Keratitis w/ exudate (protein rich fluid)
- trichiasis - eyelashes grow into eye
- scarring of conjunctiva
- Blood vessel growth in cornea?
What causes STD chlamydia?
What are symptoms?
STD caused by trachomatis d-L
Can present as:
- males*: urethritis, prostitis, epididymitis (90% sympotmatic)
- females* (mostly asymptomatic): cervicitis, , proctitis, PID salpinigitis (–>ectopic pregnancy, infertilitiy)
Can infect newborns via conjunctivitis or pneumonia
May cause scarring in host by antibody binding to hsp60
What causes inclusion conjunctivitis?
What is the resevior, and how is it spread?
How to diagnose?
What is Reiter’s syndome?
Caused by C. trachomatis (D-K)
Only in humans, spread by fomites of STDs. (Infant - acquired)
Microscopic obersvation for inclusion bodies.
Reiters: arthritis, urethritis, uveitis - cuased by antibodies self-reacting w/ self antigens.
What is LGV?
Lymphogranuloma venerum - cuased by c. trachomatis L1-3
Presents as swollen lymph nodes near genitals
what cuases Psittacosis?
How does it spread?
What are its symptoms?
Caused by C. psittaci
Comes from birds, inhalation of infectious excrement.
Atypical pneumonia - lower fever, little sputum, very mild pneumonia
How does c. pneumonia present?
How are symptoms related?
It appears in only 10% of those infected as mild URI/LRI.
In people of 60, up to 70% become symtpomatic.
Can be related to plaque formation, MS, asthma, rheumatoid arthritis.
describe laboratory diagnosis
Convalescent (chronic) pt serum has 4x antibody titer as acute.
c. trachomastits infected cells have glycogen filled inclusion bodies - use idoine/giemsa stainning
* can’t use for other Chlamydias*
PCR important (use NAAT for diagnosis of C. trachomasitis and Neisseira)
What are the 3 species of rickettsia
1/ Rickettisa rickettsii - Rocky mountain spotted fever
- coxiella burnetti - Q fever
- Rickettsia prowazekii - Epidemic Typhus (developing countries)
what are the characteristics of Rickettisa
Gram - rod that is obligate intracellular parasite that replicates via binary fission
How does it invade host?
What is Weil-Felix rxn?
- enter’s skin through arthropod bite
- Infects endothelial cells (causes petchial rash via thrombi)
- replicates via binary division
WF rxn: reckettsia antibodies attach/rxn to membrane of proteus vulgaris–> cause agglutination rxn in serum
What is Rickettsia’s pathogenesis?
In endothelial cells, cuases hyperplasia and thrombi
can cause Petechial rash in skin (via hemorrhage)
Increase in vascular permeability via LPS–>septic shock
DIC: Ricketssial endotoxin
How does ricketssia resist immune system?
If eaten by macrophage/ phagosome, can exit phagosome and remain in cytoplasm w/o a membrane covering–> no detection
How is RMSF spread?
How does it present?
RMSF lives in ticks, lives on rodent via trans ovarian route (via eggs). Vector is the tick.
Presents as rash on palm of hands/soles of feet, moves to trunk.
Can cause vascular coagulation–> death
How is the resevoir of Q fever?
How does it spread?
Coxiella burnietti, originally from sheep, as spore form.
Spreads to humans as spore throuhgh infected tissue, milk in large quantities.
In healthy hosts, no disease.
In immunocompromised, can have pneumonia–>disseminated (endocarditis/hepatitis/ sock)
What cuases typhus?
How is it spread?
What are the symptoms?
How to test/diagnose?
Typhus caused by Rickettsia prowazekii. Its resevoir is the pedicus louse (GI), which also spread the infection. Invades endothelial cells (in vessels)
VIRUS ONLY IN HUMANS.
Symptoms: rash starts on trunk, moves to hands and legs (no palms/soles)
Test: Elisa for IgM Ab (1 wk), and PCR.
Does not exist in US endemically.
What is Brill-zinsser rxn?
Antibodies of typhus cross react w/ receptors on surface of cells, causes agglutination.
Shows up as Ab -, but can cause relapse of fever.
What is appropriate prevention of the ricketsii diseases?
Vector control
RMSF - has no vaccine
Q fever- heat killed vaccine
typhus - formalin killed vaccine
If Dogs have, give DDT to kill louse.
