lecture 24-upper respiratory tract 1 Flashcards
staphylococcus epidermis
staphylococcus aureus
corynebacterium
-all nose and respiratory normal flora- both staphylococci are gram +
corynebacterium is rod gram +
streptococcus type of bacteria_
what’s unique about Moraxella catarrhalis
gram + cocci
Moraxella catarrhalis is gram neg cocci AEROBE
what are the four bacteria that go up in the winter time?
- streptococcus pneumonie
- haemophilius influenza
- Neisseria meningitides
- Moraxella catarrhalis
Streptococcus in general
type of bacteria?
catalase result?
gram + cocci
catalase neg
when looking at a slide and the bacteria is alpha hemolytic, what should you assume the bacteria is?
strep pneumoniae
what are the two beta hemolytic streptococcus bacteria?
s. pyogenes
s agalactiae
if someone has redness of the throat with pus (pharyngitis) what bacteria is this?2 ways diagnosis determined?
- streptococcus pyogenes
- it’s a beta hemolytic bacteria when other normal bacteria in throat are alpha or gamma
- rapid strep test can be done that targets the cell wall of the antigen
- > prob with rapid strep test is that results can be skewed because so quick
Strep pyogenes
catalase test?
what does it have that makes it so virulent?
- catalase negative
- has M protein that make it antiphagocytic and is essential for virulence
- has many serotypes- can infect over and over with no memory- no vaccine
- have capsule
what are strep pyogenes exotoxins? what do they do?
- 9 proteins
- super antigens from pyogenes that causes scarlet fever, toxic shock. necrotizing fascitits
- only scarlet fever is preceded by strep throat
treatment for streptopyogenes?
- PCN
- Erythromysin
what is the cause of scarlet fever?
streptococcus pyogenes release of exotoxin called erythrogenic toxin (kills RBCs and see it in agar plate)
what causes acute rheumatic fever?
strepto. pyogenes causes overwhelming inflammatory immune rxn that kills the organism but causes body to attack normal flora of the body- heart porbs, chest pain, rash, skin nodules, uncontrolled jerky mvmts
what causes necrotizing fasciitis
exotoxin release from s. pyogenes that causes a skin infection that is necrotic
acute glomerulonephritis
immune complex attack-
usually in childhood and begins 1-4 wks post strepto pharyngitis infection or 3-6 weeks after skin infection
-find antigen-antibody complexes in glomeruli
-get htn, edema, hematuria, proteinuria, decreased serum complement
what streptococcal group is streptococcus pyogenes in?
s. agalctiae
s. bovis
enterococcus faecalis
A
B
D (bovis = bovine and milk gives you vitamin D)
D
Diptheria symptoms? distinguishing factor? cause? what does it look like under microscope?
- deadly
- controlled by toxoid vaccine
- mild sore throat, slight fever, high fatigue and malaise, extreme neck swelling is often dramatic
- distinguishing factor? whitish gray membrane-tonsils, throat, nasal cavity-membrane difficult to pull off and has epithelial cells, clotted blood and mucus membrane with leukocyte infiltrate
- caused by Corynebacterium diphtheriae
- looks like Chinese letter under microscope
Corynebacterium diptheriae shape? motility? type of bacteria? what's it's main virulence factor?
-variable shape
-causes diphtheria
-non-motile
-GRAM POSITIVE ROD
-Main virulence factor: EXOTOXIN lysogenized (brought in) by bacteriophage
-
what’s notable about diphtheria toxin and how it infects?
what occurs if the disease survives?
- it is released as inactive with an A and B subunit
- B binds the host receptor
- A- inactivation of elongation factor-2 (EF2) to stop protein synth and induce cell death
- survives- heart, kidney and nerve cell damage
what are a-b subunit structure of bacterial toxins
- active protein, binding protein and usually works via ADP-ribosylation
- A goes into cell and inactivates elongation factor disabling it from making proteins and thus killing the cell
