Micro Flashcards
(26 cards)
What 3 cells are APCs (antigen presenting cells)?
- Macrophages
- Dendritic cells
- B-cells
AIDS patient with motor neuropathy has a DNA virus. What it is most likely?
JC virus (type of Polyoma virus)
Renal transplant patient on immunosuppressants has hematuria due to a DNA virus. What is it most likely?
BK Virus (type of Polyoma virus).
Transplant patient with pneumonia, retinitis, colitis. What’s the most likely DNA virus infecting the patient?
CMV (cyclomegalovirus)
What’s the treatment for CMV?
Ganciclovir is first-line (remember the green recycle bin in Sketchy)
*Fascarnet when resistance bc of UL97 gene mutation
The treatment for CMV is Ganciclovir. What’s its mechanism and hematologic side effects?
Inhibits viral synthesis by blocking CMV DNA polyemerase.
Neutropenia, anemia, thrombocytopenia (low neutrophils/ WBCs, RBCs, and platelets).
HIV patient with CD4 count below 200 has pneumonia. Broncheolavar lavage is performed for diagnosis and the organism responsible for the pneumonia is stained with a silver stain. What is it?
Penumocystis Jiroveci (“PCP ping pong” in Sketchy) fungi.
*note: broncheolavar lavage is a procedure that involves rinsing to get lung sample- less invasive than a biopsy
What are the virulence factors of the Neisseria species (Gonorrhea and Meningitis)?
Pilli (allow attachment to surfaces and display antigenic variation) and IgA protease (cleaves IgA/ cuts up IgA to stop it from working so the bacteria can continue to survive along mucosal surfaces)
What immuno problem with infection with Neisseria Gonorrhea or Meningitidis give rise to?
Inability to form the MAC complex (bc complement proteins C5-C9 are inhibited)
Which virus classes are segmented and how many segments do they have?
“BOAR”= segmented viruses
Bunyavirus (3 segments- 3 rings on tree log in Sketchy)
Orthomyxovirus (8 segments- octopus in Sketchy)
Arenavirus (2 segments- 2 circles on floor in arena in Sketchy)
Reovirus (11 segments- 11 boats on the Reo river in Sketchy)
Antigenic shift can happen in what viruses?
Antigenic shift= reassortment of viral segments (occurs in pandemics).
This happens in segmental viruses: “BOAR.” Bunya virus (California Encephalopathy, Hemorrhagic fever: Rift Valley Fever, Crimean- Congo Hem. Fever, and Hantavirus), Orthomyxovirus (influenza), Arenavirus (Lassa Fever and Lymphocytic Choriomeningitis Virus, or LCMV), and Reovirus (Rotavirus and Coltivirus).
What’s the difference between antigenic shift and drift (using influenza as an example)?
Antigenic DRIFT- point mutations in the viral genome—> changes in hemagglutinin (HA) and neuraminidase (NA) molecules. This occurs in seasonal flu epidemics.
Antigenic SHIFT- reassortment of entire viral segments. This occurs in pandemics.
What medication do you give to treat Bacteroides?
(Bacteroides is a gram negative anaerobic rod that can produce beta-lactamase, an enzyme that breaks down Penicillin)
Pipercillin
(effective against gram negative enteric rods like Pseudomonas and also against Bacteroides)
HIV patient with colitis. Cells have “owl-eye” inclusions. What is the diagnosis?
CMV colitis (cytomegalovirus, which is in the Herpes virus category)
What do you treat CMV with? There are 2 drug choices—explain when you’d use 1 over the other.
Ganciclovir is first-line CMV treatment, but requires intracellular activation by viral/ cellular kinases. Foscarnet can be used instead (in a UL97 gene mutation) because it does NOT require intracellular activation.
Ovoid bodies (macrophages filled with many yeasts) is a buzzword for which fungi?
Histoplasma Capsulatum (Histoplasmosis)
Broad Based Budding is a buzzword for which fungi?
Blastomycoses Dermatids (Blastomycosis)
A spherules of endospores is a buzzword for which fungi?
Coccidiodes Immitis (“valley fever”)
Captain’s wheel appearance is a buzzword for which fungi?
Paracoccidiodes Brasillensis
If you have a centra venous catheter placed for parental nutrition, what fungal infection of the blood are you at risk for?
Candidemia (Candida fungus in the blood)
What is the most important treatment for Diphtheria?
Administration of anti-toxin! (a pre-formed antibody to bind to bacterial toxin circulating around and inactivate it)
*you’d also give Penicillin and vaccine with toxoid…why is anti-toxin more important though than antibiotic treatment? Bc if you give antibiotics, yes they’ll work to kill bacteria, but they can’t help the EF-2 toxin that’s already been released in you doing damage. Stopping the thing doing damage is your number 1 priority (same idea as you need to remove the tampon/ source of the problem in a girl with toxic shock before giving meds will do good)
What vitamin reduces mortality in patients with Measles?
Vitamin A
What is the mechanism of action of the drugs used to treat Mcyoplasma pneumonia (most common cause of atypical/ interstitial pneumonia)?
You use Macrolides or Tetracycline, which are PROTEIN SYNTHESIS INHIBITORS.
*note: in a question like this on the test, eliminate beta-lactam drugs (cell wall synthesis inhibitors) right away bc Mycoplasma lacks a cell wall, so a cell wall inhibitor won’t help.
Synthesis of extracellular polysaccharide matrix is the virulence mechanism of which Staph bacteria?
Staph epidermidis (Produces biofilms made of polysaccharides that stick to artificial joints, heart valves, etc.)
