Chlamydia and Rickettsia Flashcards
Do chlamydia and Rickettsia grow intra or extracellularly?
Obligate intracellular bacterial pathogens
Are chlamydia and rickettsia gram positive or gram negative?
Gram negative
Name the facultative intracellular bacteria:
Salmonella, shigella, legionella
What are the three types of chlamydia and what do they cause?
chlamydophilia psittaci=parrot fever
chlamydophilia pneumoniae=pneumonia
chlamydia trachomatis=conjunctivitis
Why are chlamydia and chlamydophilia obligate intracellular pathogens?
They cannot make ATP. They can only induce ATP synthesis in host cells
What are the two stages of development of chlamydia?
Elementary bodies and reticulate bodies
What are elementary bodies?
Small, non-replicating form of chlamydia with a rigid cell wall
What are reticulate bodies?
Form of chlamydia that are larger, actively multiplying, and do not have a cell wall. They replicate through binary fission and are NOT infectious
How is chlamydia psittaci contracted?
Inhalation of bird feces from contact with parrots, parakeets, and pigeons
What are the symptoms of psittacosis?
Fever, headache, detected in blood/sputum. Occasionally can lead to interstitial pneumonia
What kind of pneumoniae does C pneumoniae cause?
atypical pneumonia. No fever.
What chronic condition is C pneumoniae linked to?
atherosclerosis
What are the different serotypes of chlamydia trachomatis?
D-K, A-C, L1, L2, L3. Different serotypes cause different diseases.
What do the D-K serotypes of C trachomatis cause?
non-gonococcal urethritis
What is urethritis?
Irritation/inflammation of the urethra
What percentage of pneumonias are caused by chlamydia pneumoniae?
10-20%
What are the possible symptoms of C. trachomatis, serotypes D-K?
- Often asymptomatic
- Purulent discharge
- Infection of epididymis or fallopian tube
- Conjunctivitis, esp in neonates. Can spread to eye
How do you test for chlamydia trachomatis serotypes D-K
Rapid PCR test
How would you treat C. trachomatis serotypes D-K?
Single high dose of azithromycin
Treat both sexual partners
What are the symptoms of a chlamydia trachomatis infection of the eye?
turned-in eyelashes, swollen eyelids, discharge, cloudy cornea
How is chlamydia trachomatis (serotypes A,B, C) transmitted?
Mechanical from finger to eye or flies
Where is chlamydia trachomatis (A, B, C) most prevalent?
Africa and Asia.
What occurs with a chlamydia trachomatis A,B,C infection?
Corneal scarring from infolding of eyelashes. Trachoma is the world’s leading cause of preventable blindness
How would you treat C. Trachoma?
Azithromycin
What do the L1, L2, and L3 serotypes of chlamydia trachomatis cause?
Lymphogranuloma venereum. Starts with a painless papule turns into an ulcer. Sometimes progresses to disease of lymph nodes
How do you treat chlamydia?
Tetracyclines. If compliance is an issue, administer a single high dose of azithromycin
What are three methods to diagnose chlamydial infections?
- Antibody titers
- Fluorescent antibody assay
- PCR
How is C. psittaci transmitted?
respiratory route
How is C. pneumoniae transmitted?
respiratory route
What is a common vector for rickettsia?
Arthropods
Does rickettsia live intracellularly or extracellularly?
Intracellularly
Describe the steps of pathogenesis in rickettsia
- phagocytosis
- slow growth
- Lysis of cell
Name the different types of rickettsia
Rickettsia prowazekii
Rickettsia typhi
Rickettsia rickettsii
Rickettsia akari
Describe the clincal symptoms of rickettsia prowazekii
- Incubation period
- Rash
- fever
How long is the rickettsia prowazekii incubation period?
10 days
When does the rickettsia prowazekii rash show up?
4-7 days later
What is the mode of transmission for RIckettsia prowazekii and typhi transmission?
Body lice. Can also be harbored in squirrels
Typhus includes what types of rickettsia?
Rickettsia prowazekii and typhi
How do you treat typhus?
tetracyclines
How do you diagnose typhus?
PCR, antigen testing, elevated liver fxn tests
What happens with R prowazekii resurfaces? What disease results?
Brill-Zinsser disease
What are the symptoms of brill zinsser disease?
Similar to primary typhus (headache, rash, elevated liver enzymes
What does rickettsia typhi cause?
Endemic murine typhus. Usually milder disease.
What are the typical hosts for rickettsia typhi?
rats and ground squirrels
What does rickettsia rickettsii cause?
Rocky mountain spotted fever
What are the symptoms of Rocky Mountain Spotted Fever?
fever, headache, abdominal pain, vomiting.
Rash on hands/feet, spreading to trunk
What type of life cycle does R. Rickettsii have? Describe it.
Trans ovarian transmission cycle
- Infected tick lays eggs in adult
- Adult harbors infected larvae
- Infected larvae attach to rodent host
- Larvae mature to nymphs then adult tick
- Adult tick jumps on human host
- cycle repeats
What symptoms does Rickettsia akari cause?
Rickettsial pox. Primary skin lesion at site of bite then systemic disease. Chicken pox-like rash
What is the mode of transmission for rickettsial pox?
Mouse mites
How would you diagnose rickettsial diseases?
PCR test
Immunohistologic detection
How would you treat rickettsial diseases?
Tetracycline
What does coxiella burnetii cause?
Q fever
What is the mode of transmission for Q fever?
inhalation of C. burnetii from placental tissue of carcasses
What are the other vectors of Coxiella burnetii?
sheep, goats, cows, cats, ticks
What are the symptoms of Q fever?
Interstitial pneumonia Fever Headache Elevated liver function tests If there is progression, leads to chronic disease
How can you diagnose Q fever?
Serology testing for coxiella burnetii
Immunofluorescence assay
Immunohistochemical staining and DNA detection
How do you treat Q fever?
Doxycycline
Quinolone antibiotics
What is the disease transmission of ehrlichioses?
Ticks
Is ehrlichiosis an intracellular or extracellular pathogen?
OBLIGATE intracellular pathogen
What are the two types of ehrlichiosis?
Monocytic and granulocytic ehrlichiosis
What are the symptoms of ehrlichioses?
Fever, lymphocytopenia, elevated liver function tests
How do you treat ehrlichioses?
Tetracycline
