lecture 3 Flashcards
what is strep throat caused by?
what kind of respiratory disease?
what are symptoms?
what can scarlet fever be caused by + symptoms?
strep pyogenes–group A strep
Upper respiratory
painful sore throat, red + swollen
pus along the tonsils + lymph nodes swollen
from strep producing a super antigen
-high fever, rash, rough skin–Strawberry tongue
what is the 2 ways strep diagnosed?
what does the antibiotic prevent?
1) throat swap— detects carbohydrate wall antigen A (on group A only)
2) blood agar— B hemolysis due to pore forming toxin
antibiotic to prevent sequelae
what are complications that can develop after S. pyogenes?
Rheumatic fever: inflammatory affecting heat, brain, connective tissue
Glomerulonephritis (kidney disease):
-immune/ complex mediated disease, which will accumulate in the kidney where the blood is filtered
-swelling everywhere
what is diphtheria caused by?
what is the fluid in the throat caused by?
-corynebacterium diphtheriae— aerobic + gram positive
-upper respiratory
-fluid into the throat from dead epithelial cells, RBC, leukocytes, fibrin, bacteria
-the fluid thickens into a pseudomembrane
-toxin can get into blood
what is the mechanism of the diphtheria toxin?
A/B toxin
B: binds the cell receptor–> entire molecule is taken up by endocytosis
- those lacking receptor are unaffected
A: enzymatically active + inactivates ribosomal protein–> stops protein synthesis
what is the diphtheria vaccine based on ?
what other toxoid based vaccines are there?
based on the toxin– toxoid vaccine
-chemically modified form, where the toxicity is suppressed but will allow the host to make antibodies to the toxin
-diphtheria, tetanus, pertussis
how does mucocillary escalator work?
how is it impaired?
–ciliated cells + mucus producing goblet cells, which propels mucus with gross stuff away
-infection, smoke, alcohol
what causes pertussis (whooping cough) in lower respiratory tract ?
what are symptoms?
what kind of toxins and what do the toxins do?
gram negative bordetella pertussis
-bursts of violent coughing with a hard time to inhale
-tracheal cytotoxin, pertussis toxin, adenylate cyclase toxin
–can cause necrosis, killing of ciliated cells, disruptions of phargocytic cells function
what is the different between P vaccine and aP vaccine in targeting DTP?
P: had several antigens
aP: acellular, may not be as effective
what are symptoms of strep pneumonia?
what bacterium is it caused by and what are its characteristics?
severe chest pain
-S . pneumoniae— heavily encapsulated with polysaccharides, which vary from strain to strain + prevents opsonization
-gram positive
what is toxin that pneumococcus produces and what does it do?
results?
penumolysin– membrane damaging toxin, which damages ciliated epithelium + phagocytes
results in reduced of microbe clearance, which then fill the alveoli
how do we diagnose pneumococcus?
does it colonize the nose?
via xray OR gram stain
-yes many ppl carry it in the nose + it doesn’t affect us because the cilliary escalator is not affected
what is the component of pneumococcus that is a virulent trait and a basis for vaccines? what is the difficulties?
capsule
each strain has different proteins that stimulate different antibodies
what can happen if pneumococci enters the bloodstream?
bactermia– bacteria in the bloodstream
meningitis— infection of membranes over brain + spinal cord
what is the bacterium that causes TB and its characteristics ?
mycobacterium tuberculosis
-slow growing, rod shaped, has cell envelope
not gram positive or gram negative
what does the surface of mycobacterium have?
can it be stained and treated by antibiotics?
—hydrophobic + impermeable cell wall– mycotic acids (long fatty acids)
-does not take up stain
-resistant to drying, disinfectants and antibiotics
what is TB taken up by and how does it avoid macrophage killing?
what is the T cell response like and what does it form when lymphocytes attack it?
via lung macrophages
–blocks phagosome-lysosome fusion –> enters cytosol + multiples
–lots of phagocytosis and lysis
–dead tissue accumulates
–delayed T cell response–> form granuloma when lymphocytes infiltrate it
why cant TB grow in granulomas?
what are most cases of TB?
bc they have too low of pH and anoxia environment
latent, asymptotic because the TB is in the granuloma
how can TB become reactivated?
HIV/AIDS
the granuloma will rupture, forming lesions–> the bacteria multiplies and is released into the airways, destroy tissue
active TB is infectious
how does tuberculin skin test work?
what does the antigens activate, which causes the lesion to form?
TB antigens is injected into the patient if
if infected, will have large, red, raised lesion
-activation of T cells, cytokine production, infiltration of other immune cells
does not distingue between latent + active
