Rickettsia

R. rickettsii

R. prowazecki

R. typhi

Coviella burnetti

Rickettsia Characteristics

Gram negative rods, so small it's hard to visualize.

Obligte intracellular pathogens.

Invade endothelial

Enter via arthropods

Rickettsial endotoxin=DIC

Escape phagosome

Rickettsia rickettsii Infection

Cause Rocky Mountain Fever

Dermacentor ticks=vector

fever, headache. Lesion Hands/feet-->trunk

Advance disease--> coma, delerium

Serious case--> coagulation, vascular collapse, DIC

Q Fever Infection

Caused by Coxiella burnetti

Domestic animal reservior

NO ARHROPOD VECTOR

Spread via infected tissue or contaminated milk

Vaccine for  @ risk=vets, herders, cow killers

Can live IN lysosome, evades enzymes!

Causes walking pneumonia, enlarged liver

Typhus Infection

Caused by R. prowazekii

Uncommon in US.. In poverty, war, lack hygiene

Lice bites, draws blood, poops. We itch and facilitate microbe entry.

Relapsing form of epidemic typhus

No vector during infection, recurrence of dormant rickettsia-milder infection shown years later

Usually Antibody negative

Diagnosis and treatment for EPidemic Typhus

Serology using ELISA or immunofluorescense is best

Treat with tetrazycline, erythromycin

Chloramphenicol good but toxic.

• Different inclusions are diagnostic
• obligate intracellular pathogen
• C. trachomatis
• C. pneumoniae
• C. psittaci
• NO PEPTIDOGLYCAN!

• A, B1, B2: Blinding trachoma, not common in US
• D-K Inclusion conjunctivitis, urthritis, cervicitus, Neonatal p neumonia, STD, common w Neisseria
• L1-3: Lymphogranuloma Venereum

* Spread via fomites and flies

* Humans only

* Examine corneal/conjunctival scraping for inclusion bodies

* Treat w tetracycline

* Can cause cervicitus in women and cause ectopic pregg

* Most common neonatal

* Inclusions in conjunctiva, used for diagnosis

* Humans Only

* associated w Reiter's syndrom

* Abs can cross react

Lymphogranuloma Venereum, an STD

Caused by C. trachomatis

Papule turns to buboes

Caused by C. psittaci

transmitted via birds, inhale infectous excretement

atypical pneumonia, interstitial respiratory disease

Treat w tetracycline

Causes URT LRT infection

Causes walking pneumonia

TWAR serotype

sample for inclusion, cannot grow in culture

• Grow in culture with actinomycin D
• Glycogen inclusions in C. trachomatis, not C. psittaci or C. pneumoniae
• Commonly, use Fluroescent Ab, ELISA, DNA hybridization, Serology for Abs for psittaci and pneumoniae.
• Treat w tetracycline and macrolides