Pathogenic Factors Flashcards
Resident microbiota _ colonize the host (after birth)
permanently
Transient microbiota _ colonize the host (dependent on the environment)
temporarily
When would normal flora cause us harm?
If it moves from where it is supposed to be to another part of the body
T/F; normal flora will look the same on an abled bodied person and a disabled person
False
What is microbial antagonism?
Normal flora preventing the growth of pathogenic microbes
T/F: normal flora competes for nutrients with a pathogen
True
T/F: when normal flora is exposed to a pathogen it will be unable to fight it off
False; they produce substances that are harmful to the pathogen
_ produce bacteriocins
E. coli
_ are proteins that inhibit the growth of closely related species of bacteria such as salmonella and shigella
bacteriocins
When would dormant spores wake up?
When normal flora is destroyed because it no longer needs to compete for nutrients
_ is a pathogen that causes a range of GI symptoms, from mild diarrhea to severe, or even fatal colitis
C. diff
Presence of normal flora in the large intestine inhibits the growth of _
C. diff
What are the 5 steps of a pathogen causing disease?
- contact/exposure
- adherence
- evasion of host defenses and penetration
- damage of host cell
- transmission
Adherence is accomplished by cell surface molecules located on the pathogen called “” binding specifically to surface “” located on the cells of the host tissues
adhesins ; receptor
What are 3 different ways a pathogen can adhere to a host?
- bacterial structures (fimbriae, pili, flagella)
- adherence proteins (M protein, opa protein)
- glycocalyx (capsule, slime layer)
Adhesins are present on the _ and _ of many pathogenic bacteria
fimbriae and flagella
T/F: the more types of adhesion proteins an organism has the more systems they can infect
True
If the glycocalyx is well organized and firmly attached to cell wall, it is referred to as a _
capsule
If the glycocalyx is unorganized and only loosely attached to the cell wall, it is referred to as _
slime layer
The slime layer facilitates the formation of _
biofilms
_; colony of bacteria that adheres to surfaces (living and nonliving), embedded in an extracellular slime layer
biofilms
T/F: biofilms are able to clog drains and corrode industrial pipes
True
_ impairs phagocytosis, preventing phagocytic cell from adhering to the microbe, thereby increasing the virulence of the pathogen
capsule
T/F: those without a capsule cause infection more quickly because it does not need to break through to infect the host
False; those without a capsule rarely cause infection because they are detected quickly by the immune system
M proteins _ virulence by helping bacteria resist _ by WBC (e.g. streptococcus pyogenes)
increase ; phagocytosis
_ present in the cell wall of Mycobacterium TB increases virulence by resisting digestion by phagocytosis
Mycolic acid
_ clot protects the bacteria from phagocytosis, and isolates the microbe from other defenses of the host
fibrin
Coagulase is produced by some _ spp.
staphylococci
All staph species are gram _
positive
_ degrades fibrin, and thus digest clots formed by the body to isolate the wound and clots created by the bacteria as protection from _
kinase ; phagocytosis
Streptokinase is produced by _ pyogenes and staphylokinase is produced by _ aures
streptococcus ; staphylococcus
Which enzyme is helpful to bacteria if they want to bust out of the clot or go deeper into the clot and tissue?
kinase
_ and _ facilitate a microbe’s ability to evade host defenses
coagulase and kinase
The production of _ also facilitates a microbe’s entry into host tissues
kinase
_ _ bacteria are able to survive inside immune cells
facultative intracellular
T/F: facultative intracellular bacteria are able to escape phagosome after fusing with host cell lysosomes
F ; they escape BEFORE fusing with host cell lysosome
T/F: facultative intracellular bacteria prevent phagosome-lysosome fusion
True
T/F: facultative intracellular bacteria are unable to reduce the effectiveness of toxic compounds within lysosome which is why they stay hidden
False; they reduce effectiveness of toxic compounds within lysosome
T/F: facultative intracellular bacteria are able to produce cell walls resistant to lysosomal proteases
True
Facultative intracellular bacteria is hidden in _ and able to hide from antibiotic therapies
phagocyte
_ acid is what holds cells together
hyaluronic
What is the job of Hyaluronidase?
Degrades hyaluronic acid allowing bacteria to penetrate deeper into the host tissues
_ degrades collagen fibers at the base of superficial tissues and allows bacteria to move deeper into the host
collagenase
_ and _ produce invasins that rearrange actin filaments in epithelial cells of the intestinal lumen
salmonella spp and e coli spp
Disruption of the _ induces “membrane ruffling” of the host cell - bacteria sinks into the _ and is engulfed by the host cell, allowing the bacteria to sink into the _ cell
cytoskeleton ; ruffles ; epithelial
For the bacteria that are not phagocytic, once inside the host, it becomes enclosed in a _ and induces an _ response
vesicle ; inflammatory
Disease results if the microbe was able to evade _ and cause _ damage
host immune response ; host cell
The pathogen needs to cause _ in order to take our nutrients (specifically iron)
damage
_ is required for the growth of most pathogenic bacteria
Iron
What strategy do microbes implore that bind to iron more tightly than host iron-transport and play “tug of war” for the iron?
Siderophores
What are two other ways besides siderophores to obtain host nutrients?
- direct binding to host iron-binding proteins
- producing toxins
T/F: bacterial toxins kill host cells, releasing the iron stores of the host; pathogen then acquires iron via receptor binding
True
How does direct damage to tissues surrounding site of invasion occur?
As intracellular bacteria and viruses metabolize and multiply in host cells, the host cell typically ruptures to facilitate their release, destroying the host cell
T/F: pathogen toxins inhibit protein synthesis, destroy blood cells and blood vessels, disrupt nervous system function
true
{Exotoxins or Endotoxins?}
Produced by gram -/+ bacteria and are produced and released by said bacteria as it is going about its daily life, directly damages host cell (cytotoxin)
Exotoxin
Which type of toxin is produced by gram - bacteria only due to their Lipid A outer membrane
Endotoxin
[Endo or Exotoxin]
Enzymatic proteins produced inside some living pathogenic bacteria as a normal part of growth and metabolism
Exotoxin
_ are secreted into the surrounding environment, or released during cell lysis
Exotoxin
[Exo or Endotoxin]
Soluble in bodily fluids and rapidly transported throughout the host; highly toxic in nature, exposure can be fatal because it will become systemic
Exotoxin
T/F: Most times the infection or problem we are seeing is not caused by the organism itself but from the toxin that has been released
True (food poisoning as an example)
Which part of the AB toxin binds to the host cell receptor for the exotoxin to enter cell
Part B
Which part of the AB toxin alters cell function by inhibiting protein synthesis?
A
Which type of exotoxin induces cell lysis via formation of protein channels (ie: leukocidins, hemolysis) or disruption of phospholipid layer of cell membrane
membrane disrupting toxins
_ provoke an intense immune response, associated with shock
superantigens
Superantigens are not processed inside _, instead bind directly to _ class II proteins on _ surface
macrophage ; MHC ; macrophage
_ exotoxin directly activate T cells -> results in excessive IL-2, TNF and TF production, these all lead to high risk of shock
superantigens
_ released when gram - bacteria are killed (or multiply) - cell wall lysis, liberating the _
endotoxin for both
Endotoxins stimulate macrophages to release high concentrations of _
IL-1
T/F: due to mechanism of action, all endotoxins produce the same signs and symptoms regardless of the pathogen
True
Why are the common symptoms of endotoxins chills, fever, weakness and generalized aches
Due to the release of IL-1
Endotoxins increase production of _; activates extrinsic & intrinsic coagulation cascade
tissue factor (TF)
What is the only exotoxin that can cause fever?
superantigens
