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29 Cards in this Set
- Front
- Back
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Do mycoplasmas have cell wall & peptidoglycan?
What does this mean for effective antibiotics? |
NO cell wall thus NO peptidoglycan
Because mycoplasmas lack a cell wall, they are resistant to beta lactams (penicillins, etc) |
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What do mycoplasms contain in their membranes?
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Sterols (cholesterol)
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How do mycoplasms grow? What kind of media?
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grow by binary fission and can grow in cell free media.
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What is the relative size of a mycoplasma?
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smallest of all bacteria
tiny pleomorphic--easily deforms to fit thru tight places |
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What is the generation time for mycoplamsas?
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1-6 hrs which is slow growth.
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How are mycoplamsmas able to lyse erythrocytes on blood agar?
What effect does this have in vivo?? |
due to elaboration of hydrogen peroxide.
This phenomenon can cause CYTOTOXICITY in vivo as well. |
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What type of parasite is mycoplasma in vivo? In cell culture?
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in vivo--primarily extracellular parasite
in cell culture--commonly intracellular |
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How is Mycoplasma pneumoniae transmitted?
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inhalation of contaminated aerosols, nasal secretions
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Where does Mycoplasma pneumoniae colonize? What is its time of incubation>
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• It colonizes the epithelial cells of the upper respiratory tract and has a prolonged incubation period of 2-3 weeks.
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How are the cilia inhibited?
What type of cells are destroyed and how? What does this allow for? |
The bacterium inhibits the function of the cilia in the respiratory tract.
P1-adhesin protein-interacts w/sialated glycoproteins of epithelial cells. Epithelial cells are destroyed by HYDROGEN PEROXIDE production leading to NECROSIS of the tissue. This can allow the lower respiratory tract to be contaminated. |
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What causes cough as a result of mycoplama pneumoniae infection?
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Destruction of the cilia and epithelial cells are responsible for the persistent cough.
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Besides pneumonia, what other problems can mycoplama pneumoniae cause?
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pharyngitis
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Can you use gram stain to determine mycoplama pneumoniae?
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No, no cell wall!!
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What age group commonly gets Mycoplasma pneumoniae?
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The disease is very common in school age children 5-15
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What is mycoplasmas major antigenic determinant?
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glycolipids--might cross react w/ human tissue
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Name 3 ways mycoplama pneumoniae can be determined in the laboratory.
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• Complement fixation (or Elisa)
• Cold Agglutinins • Culture |
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What will agglutinate in cold agglutination?
What constitutes cold? |
IgM Ab against erythrocyte I Ag.
clump at 4 C |
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Is clumping by cold agglutination reversible?
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yes
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What are the 2 hypotheses regarding Ab against erythrocyte I Ag?
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1. molecular mimicry--Ag on bacterial surface is similar to the I Ag
2. I Ag is modified by the mycoplasma to become MORE antigenic |
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What's the problem with the combination of sickle cell anemia and mycoplasma pneumoniae?
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People who have a disorder like sickle cell anemia are already more likely to have their erythrocytes deform and clump in the small capillaries.
Infection w/ Mycoplasma pneumoniae can lead to even more obstruction of these capillaries and result in necrosis of that tissue |
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Where are specimens obtained for culture of mycoplasma pneumoniae?
What must the media contain? What do colonies look like? |
throat or bronchial washings
media must contain sterol colonies look like mulberries |
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What are two mycoplasmas that are sexually transmitted?
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Ureaplasma urealyticum
Mycoplasma hominis |
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What type of surfaces do Ureaplasma urealyticum or
Mycoplasma hominis inhabit? |
mucosal surfaces of the genitourinary tract
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If a child recieves Ureaplasma urealyticum or
Mycoplasma hominis from their infected mother how long might the child have symptoms? |
Up to 2 years of age
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How does colonization result?
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sexual contact
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What disease can be caused by M. hominis? In adults? In children? In normal mothers after childbirth?
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Pelvic Inflammatory Disease ( PID), pyelonephritis, and postpartum fever
Children: neonatal meningitis and brain abscesses. occasionally normal mothers can develop arthritis of sudden onset after child birth w/ isolation of M. hominis |
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What does U. urealyticum require?
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metabolized urea and requires it for growth
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What disease can U. urealyticum cause?
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nongonococcal urethritis
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What is the group, Mycoplasma fermentans, incognitans and penetrans, thought to be implicated in?
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HIV --although association is contraversial
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