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Rickettsiae, Chlamydiae, and related


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What are the Rickettsiae and chlamydiae; three characteristics?
1. Obligately intracellular
2. Can't grow on artificial media;
3. Between bacteria and viruses.
What type of symptoms are seen in Nongon urethritis?
It's often asymptomatic.
Females MAYBE white scanty discharge.
What is used to treat
-Rickettsia, Coxiella, Orientia?
-Chlamydia, Ehrlichia, Bartonel?
1. Erithromycin/tetracycline
2. Doxycycline/Azithromycine
What 4 lab methods are used to diagnose Rickettsiae/Chlamydiae?
1. Serology (most common) especially IFA!
2. Molecular methods
3. Tissue culture
What three infections does Chlamydia trachomatis cause?
1. Genital tract infections
2. Trachoma
3. Lymphaogranuloma venereum
What type of development do the Chlamydiae go through?
3-cycle: Elementary body, intermediate body, and reticulate body.
Which stage of development is the infectious one?
What species causes the well-known Chlamydia?
Chlamydia trachomatis
What does Chlamydia trachomatis cause in adults?
Nongonococcal urethritis, an STD genital tract infection.
What 3 side effects does PID cause in females?
-Ectopic pregnancy
-Spontaneous abortion
-Premature birth induced
What is a severe infection Chlamydia especially causes in women?
Pelvic inflammatory disease
What does C. trachomatis cause in infants? What else can it develop into?
Inclusion conjunctivitis; can progress to neonatal meningitis.
What 4 organisms cause neonatal meningitis?
1. Strep grp B
2. C. trachomatis
3. Haemoph. type B
4. Chyrseobact. meningosept.
What is Trachoma?
chronic conjunctivitis where the cornea sloughs off from eyelashes scraping.
What else does C. trachomatis cause?
Lymphogranuloma venereum.
what is lymphogran venereum?
an STD that causes genital lesions, inguinal bubos.
What 3 ways is C. trachomatis diagnosed in lab?
1. Cell/tissue culture (gold standard).
2. Immunological (DFA/EIA)
3. Probes/amplif. techniques
What causes TWAR?
Chlamydia pneumonia.
what is TWAR?
Taiwan acute respiratory
What is TWAR possibly associated with?
1. atherosclerosis
2. Alzheimer's disease
3. Chronic autoimmune diseases like MS.
What does Chlamydia psittaci cause?
Psittacosis/Ornithosis - zoonotic lung infection.
What type of infection is Psittacosis?
Zoonotic in humans because its a disease of birds.
What are the 4 Rickettsiaceae genera?
1. Rickettsia
2. Orientia
3. Ehrlichia
4. Anaplasma
How are Rickettsiaceae usually transmitted?
Via arthroporids
What 4 symptoms do Rickettsia and Orientia infections have?
1. Lesions at the bite site
2. Rash
3. Fever
4. Headache
-Primarily what infection is associated with Rickettsia?
-What species causes it?
Rocky mountain spotted fever - caused by R. rickettsii
-Where is RMSF found?
-What transmits it?
-What are its hosts?
-Therefore what type of inf.?
-In the SouthEast of U.S.
-Ticks, dogs, rodents, humans.
-Zoonotic infection
How many Rickettsia sp are there?
18 - the 17 others cause milder infections not in the U.S.
What are the 2 groups of Rickettsia/Orentia?
1. Spotted fever group
2. Typhus group
What are the 3 types of Typhus caused by the typhus group?
1. Epidemic (louse-borne)
2. Endemic (murine)
3. Scrub
What organism causes:
-Epidemic typhus
-Endemic typhus
-Scrub typhus
Epi = Rickettsia prowazeki
End = Rickettsia typhi
Scrb = Orientia tstusugamushi
What vector transmits R. typhi, endemic typhi?
What transmits scrub typhi?
What symptoms are associated with Endemic/Epidemic typhus?
Scrub typhi?
-Same as RMSF

-Rash on trunk
What vector transmits Ehrlichia and Anaplasma?
What 2 diseases are caused by Ehrlichia and Anaplasma?
1. Human Monocytic Ehrlichiosis
2. Human Granulocytic Ehrlichiosis
What is the geographical distribution of Ehrlichiosis?
same as lyme's disease
What are 3 types of symptoms of Ehrlichiosis?
1. Fever/myalgia/headache
2. Rash in HME
3. Critical septicemia
What are the 4 lab findings in Ehrlichiosis?
1. Leukopenia
2. Thrombocytopenia
3. WBC inclusions - morulae
4. Serological/PCR test results
What type of testing is used to confirm Ehrlichiosis?
Paired sera - during infection and convalescent.
What causes Q fever?
What is Q fever?
How is it transmitted?
-Coxiella burnetii
-A febrile disease which involves the lungs.
-Aerosol transm. from livestock.
What is Coxiella burnetii diagnosed with?
Immunofluorescent antibody
Why do we even care about Coxiella burnetii?
Bioterrorism - it is a category B agent; moderately easy to disseminate.
What last group of the Rickettsiaceae is stuck there?
What is funny about Bartonella?
-Not a Rickettsiaceae
-Not obligately intracellular
What are the growth characteristics of Bartonella?
Fastidious organism that grows on CA; Short GNB, oxidase negative.
what are the 2 species of Bartonella? What infection does each cause?
1. Bartonella quintana - Trench fever
2. Bartonella henselae - cat scratch fever
What vector transmits Trench fever? What symptoms does it cause?
-Body lice
-Can cause endocarditis.
What is the natural habitat of Bartonella henselae?
What symptoms does it cause?
Cats and Cat fleas.
Lesions at scratches, lymphadenopathy, systemic inf.
How are Bartonella species diagnosied?
What 2 STDs exhibit Urethritis, Cervicitis, or PID (if untreated)?
In whom can Chlamydia trachomatis cause infections?
-Males (few though)
-Females (mostly)
-What do Infants get from Chlamydia infection?
-How can it be prevented?
-Inclusion conjunctivitis - -Administer antimicrobial eye drops as prophylactic treatment.
What can inclusn conjunctivitis potentially develop into?
Neonatal pneumonia
What is the world leading cause of blindness?
What's trachoma again?
Chronic conjunctivitis.
What 2 STDs does Chlamydia trachomatis cause?
-Nongon urethritis
-Lymphogranuloma venereum
What causes lymphogran. venereum?
A Rare serotype of C. trachomatis
What is the method of choice for diagnosing chlamydia?
Cell culture - but it is not practical for routine lab use b/c it takes too long.
What is the specimen of choice for diagnosing chlamydia?
What else can be used?
-A urethral swab - w/out cotton, wood shafts, lubricant.
-Can use 1st voided urine for molecular testing
What is the suggested diagnostic approach for clinicians for ehrlichiosis?
1. If Patient has been exposed to ticks and exhibits symptoms.
2. Order peripheral blood smear, CBC, hepatic liver enzymes.
3. Order acute IFA andPCR
4. Empirically treat with doxycycline
5. Order 2-3 wk later convalescant IFA

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