Exam2Lec5ICBacteria Flashcards
How do intracellular pathogens get inside the cell?
Taken up by cell and create a endosome or phagosome
1. can escape endosome
2. prevent fusion with lysosomes so they cannot be broken down
3. fuse with lysosomes to form phagolysosome but survive in the phagolysosome
How do the intracellular bacteria get around?
ACTIN ROCKET
The bacteria hack the cytoskeleton and begin an actin tail assembly to be motile. Once motile with actin tail they can push to other cells
What are the facultative intracellular bacteria talked about in class?
Mycobacterium tuberculosis
Bartonella henselae
What are the general characteristics of the genus mycobacterium?
aerobic, gram + rods
Acid fast:
—- bind phenol-based dyes in presence of heat
—–retain dye when treated with acidified alcohol
How does acid fast work?
-bind phenol-based dyes in presence of heat
-retain dye when treated with acidified alcohol
why do we have to do an acid fast stain on Mycobacterium?
Complex cell wall lipids
-include mycolic acids–>waxy envelope so it is hard to penetrate
What is the growth speed of Genus mycobacterium?
VERY SLOW ~3 weeks to grow from small inoculate
Extra:
- Generation time:
—–15 - 20 min for E. coli
—– 60 min for C. diphtheriae
—— 300 min for M. tuberculosis
What is included in the complex cell wall lips of genus mycobacterium?
mycolic acids
The waxy layer or complex cell wall lipid of genus mycobacterium does what?
protects vs. phagolysosomal components, probably basis for survival in macrophages
What are the components of the mycobacterium cell envelope? List them
A = cell memebrane
B = peptidoglycan
C =arabinogalactan
D = lipoarabinomannan–> like LPS but not LPS
E = proteins
F = mycolic acids
G = surface glycolipid
Who has an increase susceptibility of TB?
Substance abusers, AIDS patients
What is the fatality rate in untreated TB?
50%
What is the transmission of tuberculosis?
Airborne droplets
Where do the TB pathogens usually reside in human body to cause infection first?
Macrophages in alveoli
what do TB x-rays look like?
patches of white lesions
Talk out the procession of tuberculosis
If you have little or no hypersensitivity, are you tuberculin negative or positive?
Negative
If you are tuberculin negative, what happens?
progressive systemic disease and death
If you have little to no hypersensitivity to TB, what happens?
progressive systemic disease and death
If your patient has a delayed type hypersensitivity and cell mediated immunity to TB, are they tuberculin negative or positive?
Positive
If a patient is tuberculin positive, what happens?
Disease is contained, bacteria live but fail to replicated
What T cells response to TB in tuberculin positive patients?
Th1
what occurs in 25% of cases in tuberculin positive cases five years later ?
Ghon complex–> lung damage
What is the end result when a patient is tuberculin positive?
91% no disease
6% clinical TB
2% Pulmonary
1% both
3% progressive systemic disease and death