Intracellular and Spiral Bacteria - MVP Flashcards
What is the Mycoplasmataceae cell wall made of?
Gram positive/ Gram negative?
How do they stain?
They do not have cell walls.
They stain gram negative (red) but are not truly gram negative or gram positive
Which Mycoplasmatacae produces urease?
Ureaplasma
Describe Mycoplasmatacae in terms of intracellular/extracellular
In the environment, it is an extracellular bacteria, but in the human host, it is an intracellular parasite
What is this?
erythema multiforme
(associated with Mycoplasma pneumoniae)
What is atypical pneumonia?
pneumonia which does not respond to penecillin as normal pneumonias do
When would you suspect an infection by Mycoplasma pneumoniae?
1
•Causes atypical “walking” pneumonia, acute tracheobronchitis, and bronchiolitis
2 cold agglutinin (anti-I IgM) production
3
- Associated with Stevens-Johnson syndrome (skin sloughing)
- Associated with erythema multiforme
Which bacteria can cause non-gonococcal urethritis, cervicitis and pelvic inflammatory disease? (four)
Mycoplasmataceae:
M. genitalium, M. hominis
Ureaplasma urealyticum
and Chlamydia trachomatis
Which drug are 45% of Ureaplasma infections resistant to?
tetracyclines
How are M. genitalium, M. hominis and Ureaplasma urealyticum diagnosed?
Special cultures are required, so these are often treated empirically.
What are these cells infected with?
Chlamydia
Describe Chlamydia:
Gram staining?
Intracellular/extracellular?
Shape?
gram negative (true)
intracellular parasite
variable - “coccoid to short rods”
What are the two terms for the stages of Chlamydia’s life cycle?
What do they mean?
Infectious elementary bodies
outside the cell - able to attach and are internalized by susceptible host cells
Intracellular reticulate (initial) bodies inside the cell - replicative form
Why MUST Chlamydia replicate inside a host cell?
It can not produce enough ATP to replicate on its own.
(actually, seems that it can’t produce any at all?)
It must use an ATP/ADP translocator to comandeer host ATP
Which type of Chlamydia causes upper and lower respiratory tract infections?
C. pneumoniae
(strain TWAR, but probably not important to remember that)
What do serovars A, B, Ba & C of Chlamydia trachomatis cause?
Trachoma conjunctivitis (a severe conjunctivitis) with inclusion bodies that can lead to clouding of cornea and trichiasis (inward growth of eyelashes that can produce severe scarring and blindness)
(seen primarily in children in Africa and Asia)
What do serovars D-K of Chlamydia trachomatis cause?
Nongonococcal urethritis, epididymitis, pharyngitis, cervicitis, salpingitis, endometritis, pelvic inflammatory disease, inclusion conjunctivitis (paratrachoma - similar to, but less severe than, trachoma), and neonatal pneumonia
What do serovars L1, L2, & L3 of Chlamydia trachomatis cause?
sexually transmitted lymphogranuloma venereum
Small, painless papule or pustule followed by tender lymphadenitis (buboes).
Origional lesion may or may not be present
How is Chlamydia psittaci transmitted?
What does it cause?
Inhaled - transmitted by birds
atypical pneumonia and “associated systemic symptoms”
Psittacosis - In psittacine birds (parrots, lovebirds, & parakeets)
Ornithosis – In non-psittacine birds (domestic fowl, ducks, pigeons, turkeys, and many wild birds)
Some sources will refer to both as Psittacosis
How is Chlamydia diagnosed?
Clinical presentation
***Identification of inclusion bodies***
PCR
Tissue Cultures
Serology
How are all Rickettsia species transmitted?
arthrapod (insect) vector
Bacteria then enter endothelial cells via “induced phagocytosis”
What are these cells infected with?
Rickettsia
How does Rickettsia aquire ATP?
It can not produce enough ATP to replicate on its own.
(but it can produce some)
It must use an ATP/ADP translocator to comandeer host ATP
Describe Rickettsia:
Gram staining?
Intracellular/extracellular?
Shape?
gram negative
obligate intracellular
“pleomorphic” (variable) coccobacilli
What is the pathogenesis that is common to Rickettsia species?
Steals host ATP
Replication causes cell lysis
Produces endotoxin
Initial replication occurs at the site of entry
producing a local lesion
followed by vascular dissemination.
Vasculitis ensues, causing
fever, headache and skin rash (petechial hemorrhage)
How is Rickettsia prowazekii transmitted?
How does it present?
What is another name for it?
transmitted
- human to human via human body louse
- in U.S. via flying squirrels)
presents with:
Fever, horrendous headaches with photophobia, hemorrhagic rash that spares palms & face
called:
“epidemic typhus”
How is Rickettsia akari transmitted?
How does it present?
Also known as?
transmitted from mice via mites
presents with vesicular (as opposed to hemorrhagic) rash
AKA: rickettsial pox
**this is the lowest yeild of the Rickettsia species**
What is another name for Rickettsia typhi?
How is it transmitted?
How does it present?
endemic/murine typhus
spread from rats via rat flea
Fever, headache, etc., plus centrifugal maculopapular rash
What is another name for Rickettsia rickettsii?
How is it transmitted?
How does it present?
Rocky Mountain spotted fever
(actually more common in southeast-southcentral USA)
spread from other mammals via ticks
Fever, etc. plus centripetal (extremities first) maculopapular rash
What is the Weil-Felix test useful for?
Why is it unusual?
How is it done?
Used with clinical presentation to diagnose Rickettsia infections
The test uses Proteus vulgaris antigens.
These antigens also happen to react with Rickettsia antibodies.
Patient’s serum is mixed with Proteus vulgaris antigens.
If a reaction is observed, the test is positive.