Lecture 11 - Rickettsia, Chlamydia & Mycoplasma Flashcards
How is Rickettsia spread?
Arthropod-spread, Humans are ‘accidental hosts’
What circumstances do Rickettsia need to survive?
They are obligate intracellular parasites
T or F, Rickettsia are small, stain poorly with gram stain and are gram negative coccobacilli
True
Why are Rickettsia obligate intracellular parasites?
They lack many of the enzymes required to produce amino acids and thus depend on host derived AA.
How is the bacteria spread and its mode of infection?
Infected tick, mite, louse or flea defecates as it eats its blood meal
Person itches the site which brings feces and bacteria in contact with wound
Bacteria enter blood stream and infects endothelial cells
Replicate slowly, affect adjacent endothelial cells, kil them and cause local blockage of blood flow (Rash)
What are symptoms of Rickettsia infection?
Fever, chills, rash and headache
What may occur in severe cases of Rickettsia infection?
Can cause vascular damage in multiple organs and tissues
Most of the symptoms of Rickettsia are due to what?
LPS flooding blood stream
What is the most common and important disease of Rickettsia
Typhus
Name the three different Typhus diseases
- Epidemic Typhus
- Endemic Typhus
- Scrub Typhus
What vectors are associated with each of the three typhus diseases?
Epidemic Typhus - Louse
Endemic Typhus - Flea
Scrub Typhus - Mite
Which of the three typhus diseases is unique and have humans as the reservoir?
Epidemic Typhus. We are reservoir or our clothes are.
R. prowazekii is associated with what disease?
Epidemic typhus
Which of these do Rickettsia have? LPS, Cell Wall
Both
What is the treatment for Epidemic Typhus
Sanitation and antibiotics
R. Rickettsii can cause what common disease?
Rocky Mountain spotted fever
Where are R. Rickettsii infections common?
SE state of U.S.
Is Rickettsia local or systemic?
Systemic
What circumstances do Chlamydia need to grow and be successful?
They are obligate intracellular parasites. They are energy parasites and steal ATP from host cell.
Which of these does Chlamydia have? LPS, Cell Wall
No Cell Wall!!
2 lipid bilayers and LPS are present
What are the 3 major species of Chlamydia
C. trachomatis
C. pneumoniae
C. psittaci
Which of the three major species of chlamydia is a bird pathogen?
C. psittaci
What two important respiratory infections does C. pneumoniae cause?
Bronchitis and Pneumonia
What is the most common cause of infectious blindness?
Trachoma
C. trachomatis has two important and serious disease. What are they?
Trachoma
STI
Is C. trachomatis local or systemic
Local
Trachoma is common in what age groups?
Children
How is Trachoma transmitted?
Transmitted eye-to-eye by tears, hands and flies
What is the treatment for Trachoma?
No vaccine, Prevention is good hygiene
What is the most common bacterial STI in the U.S.
C. trachomatis
What type of infection is C. pneumoniae?
community-acquired respiratory infection
How is C. pneumoniae related to atherosclerosis?
Clear association but role is unclear. Thought that chlamydia directs cells to produce lipids at 5x the normal rate
What bacteria is the smallest self-replicating organisms with smallest genomes?
Mycoplasma
Which of these does Mycoplasma have? LPS, Cell Wall?
None, No Cell wall or LPS
What is significant about the cell membrane on Mycoplasma?
Contains sterols. No LPS or Cell Wall
What is the major cause of “walking pneumonia”?
M. pneumonia
Does penicillin work for mycoplasma treatment?
No, No cell wall
What sets M. pneumonia a part from Chlamydia and Rickettsia?
M. pneumonia is an Extracellular pathogen whereas the other two are obligate intracellular parasites
