Mycobacterium TB and Non TB Myco Flashcards
is TB more likely to be diagnosed in a native US resident or a foreign born resident?
14 times more likely in a foreign born resident
what is the relationship between TB and HIV? what does this mean?
it is syndemic…HIV makes TB worse and TB makes HIV worse
why is it hard to diagnose TB in an individual with HIV?
diagnostic tests use T cells and HIV patients have limited T cells
name the four commonly used TB drugs
isoniazid, rifampicin, pyrazinamide, ethambutol
in multi drug resistant TB, what two drugs are people resistant to?
rifampacin, isoniazid
what is DOTS?
directly observed treatment short course
what is the name of the TB vaccine?
bacillus calmette guerin (BCG)
what type of vaccine is the BCG vaccine?
live attenuated mycobacterium bovis
is the BCG vaccine given in the US? why?
no…mainly because of highly variable efficacy and its issue with the TB tests
mycobacterium is facultative intracellular, what does this mean?
it can live in or outside of cells
what cell does myco TB usually reside in?
macrophages but can also live in dendritic cells
since myco TB can be intracellular what arm of immunity do individuals rely on?
cell mediated T cell immunity
is mycobacterium acid fast or not? gram pos or neg?
it is acid fast…neither gram pos or neg
what is the peptidoglycan in myco TB linked to externally?
arabinogalactan
what is the unique feature on the outer surface of myco TB?
mycolic acids
does myco TB have LPS?
no the mycolic acids make up the outer membranes instead
how is myco TB transmitted?
airborne and inhaled as aerosols
what type of room should patients with TB be in?
negative pressure meaning air flowing into room and then outside
what can make myco TB last so long?
it is able to survive in macrophages
name two ways myco TB resists attacks from macrophages?
can resist the reactive oxygen and nitrogen
can block the maturation of phagosomes
how does myco TB get from macro to macro in the body?
it grows a ton in a macrophage and causes it to lyse…releasing all the TB that can be picked up by other macros
what is the important cytokine that the macro produces that can help fight TB?
IL-12
why is IL-12 important for TB?
drives the Th1 response which is good at intracellular defense by further activating macrophages
the Th1 cells that are activated by IL-12 in TB infection leads to the release of what cytokine? how does this cytokine help with myco TB control?
IFN-gamma will inhibit the further growth and activates the macrophages to kill the myco TB
why does a granuloma form in myco TB?
to wall off the infection and keep it localized
what causes the latency in myco TB?
the granulomas can contain a latent living myco TB that is replicating very slowly or not at all
are the granulomas that are formed with myco TB homogenous?
NO..can be very different
with a later stage granuloma in myco TB, what happens to the outside of the granuloma? what is the granuloma called now?
it is walled off by fibrin…called a tubercle
how does a person become infectious with TB?
when their granulomas re activate and start to release the extracellular myco TB
what happens when you have a reactive myco TB reaction?
the immune system puts on a powerful response and can cause lung damage and release of the bacteria from the granulomas to other locations
what are the symptoms of active TB?
cough, coughing up blood, chest pain, weight loss, fever, night sweats
are the symptoms of TB due to the bacteria or the inflammatory response?
the inflammatory response
what two things make drug treatment so difficult in myco TB?
granulomas penetration is pretty difficult
myco TB is very slowly replicating
name the other three acid fast mycobacterium
myco Bovis
myco Leprae
non TB myco
