Chlamydia, Rickettsia, and Friends Flashcards
C. pneumonia: clinical
- mild URT
- mycoplasma-like pneumonia (“walking”)
- associated with atherosclerotic plaques, asthma, stroke, Alzheimer’s
C. pneumonia: carriers
- koala bears (zoonosis)
- high infection rate
C. pneumonia: treatment
- usually untreated
- tetracycline
C. psittaci: clinical
- “parrot fever”
- acute, SEVERE pneumonia & sepsis
- well-defined lung involvement
C. psittaci: carriers
- psittacine birds by bites or feces inhalation
C. psittaci: treatment
- tetracycline
- quarantine birds
Chlamydia trachomatis: features
- G-, obligate intracellular parasite; not a true PG in cellwalll; 15 serovars based on LPS antigens; 2 forms EB (infective, .3um) & RB (replicative, 1.0um)
- STD or CONTACT transmission
Chlamydia trachomatis: clinical
- Trachoma: infected birth canal OR by contact or mech vector (flies) -> keratinized cornea (pannus) -> trichiasis -> lead to blindness
- Inclusion Conjunctivitis: not as severe as trachoma (neonates), poss. Resp. complicate 3. Neonatal Pneumonia: no fever; shorness of breath, suspect if along with inclusion conjunct.
- Chlamydia: co infection with gonorrhea 40%; males – nongonococcal urethritis, epididymitis, prostatitis; self-limiting; females – PID (most common cause), nongonococcal urethritis, cervicitis, salpingitis ! infertility
- Latent lymphogranuloma venereum: small abcess ! inguinal buboes (fever, pain, block), ddx with plague-never cervical; can cause elephantiasis or bowel obstruction
Chlamydia trachomatis: carriers
- leading cause of preventable blindness
- STD most common in developed countries
- tread both localizations (can cross- infect)
- easier to break DS in RB - manifestation depends on serovar
Chlamydia trachomatis: virulence
- EBs cause invasiveness via T3SS remodel host cytoskel. - LYSOZYME RESISTANT
- inhibit phagolysosome fusion living/proliferate in endocytic vesicle
- induce cytokine (IL-1) -> inflammation
- live intracellularly for a long time
Chlamydia trachomatis: treatment
- vaccine ineffective
- preferred azithromycin (one-dose, oral)
- also TETRACYCLINE or macrolides
- surgery or epilation for trichiasis
- Expedited partner therapy (EPT)
- many asymptomatic so NEED TO SCREEN
Rickettsiae: features
- 4 medical groups, small road
Rickettsiae: clinical
- obligate intracellular parasite
Rickettsiae: carriers
- yolk sac
Rickettsiae: virulence
- MOST infectious organism known (1cell) - Cell type tropisms
- Phospholipase A targets cell membranes -Multiply INTRACELLULAR then spread
Rickettsiae: treatment
- Remove vector
- Doxycycline – start SOON - Q-fever vaccine (Australia)
Typhus group (Rickettsiae): features
G-, R. prowazekii (lice) typhi (flea), akari (mite), Orientalia tsutsugamushi)
Typhus group (Rickettsiae): clinical
- grow in host cytoplasm
- parasite vascular endothelium ! vasculitis, rash (CHEST ! extremity) - high fever, severe prostration (R. Prowazeki)
- mild symptoms with R. typhii
- R. akari ! smallpox-like rash (R. pox)
Typhus group (Rickettsiae): carriers
- louse or rat flea (Eschar at bite site
Spotted Fever group (Rickettsiae): features
G-, R. rickettsii, grow in host cytoplasm
Spotted Fever group (Rickettsiae): clinical
- endothelial pathogen, rash on
EXTREMITIES FIRST ! trunk - Rocky Mountain Spotted Fever: fever, headache, nausea, vomiting, m., joint, abdominal pains (from organ vasculitis)
Spotted Fever group (Rickettsiae): carriers
- Dog-tick or wood-tick
- Maintained in host via transovarian cycle
Spotted Fever group (Rickettsiae): virulence
- Escape from phagosome to divide and then lyse cell
- Lyses SMOOTH MUSCLE – Rhabdomyolysis
Ehrlichia chaffeensis,
Anaplasma phagocytophilum group: features
NOT G-
Ehrlichia chaffeensis,
Anaplasma phagocytophilum group: clinical
- Chlamydia-like (RB-EB), inside monocytes, granulocytes
- Ehrlichia – headache, myalgia, thrombocytopenia, lymphopenia, bone marrow granulomas; usually NOT vasculitis (rash <50%)
- Anaplasma – 10% rash
Ehrlichia chaffeensis,
Anaplasma phagocytophilum group: carriers
- Zoonotic infection from ticks (WI, MN)
Ehrlichia chaffeensis,
Anaplasma phagocytophilum group: virulence
NO PG OR LPS
- Ehrlichia – immune response (decr. TNF- alpha and increase late in infection) – parasite of MQ and monocytes (leuko.)
- Inhibits fusion with phagolysosome
- Anaplasma – parasite of neutrophils & granulocytes, pathology from immune
Coxiella burnetti: features
NOT G-, grow in phagolysosome
Coxiella burnetti: clinical
- Q-fever – resembles flu or pneumonia - parasite of endothelial cells, chronic ! endocarditis (those with defective heart valves)
- granulomas in liver, spleen, bone marrow
- Fever with pneumonic/hepatitis 2-3 post-exposure
Coxiella burnetti: carriers
- Infected via dust or aerosols from infected animals
- High in placenta
Coxiella burnetti: virulence
- Infect lung epithelia
- LIVE INSIDE the phagolysosome (digestive enzyme and pH resistant)
Coxiella burnetti: treatment
- Sulfonamides ENRICH growth
