Lacount TB Flashcards
name the organism that causes TB
mycobacterium tuberculosis
what is acid fast bacteria
when stained with dye it does not get decolorized but remains red
what keeps the red dye from being decolorized
mycolic acid rich cell wall
composition of the mycobacterial cell wall
mycolic acid rich region
arabinogalactan
peptidoglycan
lipid bilayer
isoniazid activation
KatG protein
isoniazid MOA
forms adducts with NAD and NADP which inhibits InhA (part of FAS II) blocking mycolic acid synthesis and causing defective cell wall
resistance to isoniazid
over expression of InhA
KatG mutation not allowing activation of isoniazid
adverse effects of isoniazid
hepatitis
peripheral neuropathy
pyrazinamide activation
activated by pncA
active only at pH <5.5
pyrazinamide MOA
inhibits panD leading to inhibition of coA synthesis
pyrazinamide resistance
mutations in pncA (can’t get activated)
adverse effects pyrazinamide
joint pain
hepatitis
ethambutol MOA
inhibits mycobacterial arabinosyl transferase so there will be defective cell walls due to this layer not being made (arabinogalactan cant be made)
ethambutol resistance
overexpression of mutations in arabinosyl transferase
ethambutol use
in combo with rifampin
adverse effects of ethambutol
optic neuritis
rifampin MOA
binds to RNA polymerase deep within the DNA/RNA channel, blocks path of elongating DNA and prevents RNA synthesis
adverse reaction rifampin
orange urine, tears, sweat
hepatitis
CYP interactions
most effective first line agent
rifampin
moxifloxacin MOA
traps gyrase on DNA as ternary complex, prevents resolution of supercoils and disrupts DNA replication
bedaquiline MOA
inhibits ATP synthase
bedaquiline resistance
mutations in atpE (target enzyme)
pretomanid activation
prodrug activated by Ddn
pretomanid MOA
inhibits mycolic acid production
ATP depletion
BPaL treatment
bedaquiline
pretomanid
linezolid
second line TB agents
streptomycin
ethionamide
para-aminosalicylic acid
cycloserine
capreomycin
lice transmission
direct contact
lice population
children aged 3-11
pinworms population
school aged children 5-10
pinworms spread
fecal-oral route
lice symptoms
itching
pinworms symptoms
perianal itching
pyrethrin use
lice
pyrethrin MOA
nerve membrane sodium channel toxins that do not affect potassium channels
spinosad use
lice
spinosad MOA
nicotinic acetylcholine receptor agonist causing rapid excitation of insect nervous system causing death
albendazole use
pinworms
albendazole MOA
binds to tubulin and inhibits formation of microtubules
caps microtubules so they can’t continue adding
albendazole selectivity
dose bind mammalian tubulin but has higher specificity for helminth tubulin
pyrantel pamoate use
pinworms
pyrantel pamoate MOA
depolarizing neuromuscular blocking agent causes release of acetylcholine and inhbition of cholinesterase
insect that transmits malaria
female mosquito
which organisms cause most malaria infections?
plasmodium falciparum
plasmodium vivax
which organism can cause relapse of malaria
plasmodium vivax
how do plasmodium species metabolize hemoglobin
parasites injest hemoglobin and degrade it to amino acids and free heme in food vacuole
how does chloroquine result in buildup of toxic heme
chloroquine accumulates in food vacuole and inhibits heme polymerization (more free heme that is toxic)
Artemisinin MOA
free radicals formed inhibiting translocation, proteosome, mitochondria
inhibit PfPI3K
artemisinin activation
must be activated by heme ion
arteminisin functional group
endoperoxide
chloroquine MOA
interfere with heme polymerization with accumulation in the food vacuole creating toxic heme
primaquine MOA
spontaneously forms hydrogen peroxide
primaquine activation
activated by CYP2D6 via hydroxylation
what is drug of choice for liver stages (active growing hypnoxoites)
primaquine
doxycycline targets what
apicoplast
