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Microbiology Chapter 15

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Pathogenicity
What is the term meaning the ability to cause disease?
virulence
what is the term for the measurement of that ability?
Portal of entry, adherence, penetration into the host cell, evasion, damage to host tissue
Steps of microbial mechanisms?
mucous membranes, skin, parenteral route
What are the three ways microbes get inside host?
respiratory tract
What is the easiest and most often used mucous membranes use for portal of entry?
Gastrointestinal
what is the mucous membrane portal of entry where most microbes are killed here by HCI and enzymes and if survives can be transmitted via feces?
pneumonia, tb, influenza, measles, small pox
What are some examples of the microbes that enter through the respiratory tract?
typhoid fever, poliomyletitis, shigellosis
What are some examples of the microbes that enter through the Gl ?
Genitourinary tract
what is the portal entry for STD's?
unbroken mucous membranes, cuts or abrasions
how do microbes enter throug the GU?
genital warts, herpes, HIV
What are some examples of the viruses that enter through the GU?
skin
when microbes enter through hair follicles, sweat glands, or by boring through this tissue they are using what tissue as a portal of entry?
parenteral route
When microbes enter through punctures, injections, bites, cuts, surgery, or splitting they are using what portal of entry?
samonilla typhimurium (ingested), streptococcus pneumoniae (inhaled), yersenia pestis (bubonic plague- no prefered portal)
What are some examples of disease that can cause disease using a specific mode of entry?
ID50
if the infectous dose for a sample of population is 50% how would you express this measurement of virulence?
the lower the number the higher the virulence
what does a low number in infectous dose or lethal dose measurements mean in regards to the virulence?
LD50
If the lethal dose for a sample of population is 50% how would you express this measurement?
letal kills and infectous get sick
what is the difference between lethal dose measurements and infectous dose measurements?
surface molecules called adhesins or ligands
In adherence how what helps the microbe adhere to the host?
biofilm
What is the term for communities of microbes and their products that attach to surfaces?
65%
Biofilm is what percentage of all bacterial infection?
penetrate the host cell
What must the microbe do to infect a host cell after it attaches to it?
plasma membrane
When the microbe attaches to the host cell it causes changes in the host cell what?
use of capsule, components of the cell wall (M protein), enzymes (such as coagulase, kinases, hyaluronidase, collagenase, IgA proteases), and antigenic variation
What are some of the ways that microbes employ evasion?
by using M protien
what components of a cell wall does a microbe in evasion?
coagulase
What enzyme clots fibrin?
shields microbe from WBC
How does the enzyme coagulase help the microbe in evasion?
kinase
what enzyme breaks down fibrin?
breaks away from blood clot when immune cells try to isolate the microbe
how does the enzyme kinase help the microbe in evasion?
hyaluronidase
what enzyme breaks down hyaluronic acid?
spreading factor (move through cells)
How does the enzyme hyaluronidase help the microbe in evasion?
collagenase
what enzyme breaks down collagen?
IgA proteases
what enzyme destroys IgA antibodies?
alters surface proteins so that it can not be fought with existing antibodies
How does the microbe use antigenic variation?
using host nutrients
How does the microbe damage the host tissues?
produce siderophores, siderophore bind to iron, siderophore binds to bacteria, bacterium takes siderophore inside
What are the step that the siderophores go through to get the nutrients (iron) and bring it back to the bacterium?
siderophores
what is the protein that bind iron stronger that hemoglobin
multiplying until cell ruptures, depriving host cell of needed nutrients, producing toxic waste products, and toxins
What is the direct damage to host tissues?
toxin
what is the poisonous substances that are mostly protein enzymes?
toxigenicity
what is the measure of the virulence of the toxin
toxemia
What is the term that refers to a toxin in the blood?
exotoxins and endotoxins
What are the two types of toxins?
exotoxins
What is the product that is produced by bacterium and secreted by proteins, is usually carried on plamid or prophage, diffuse easily into the blood, can be produced by gram negative and positive and is the most lethal substance known?
Antitoxins
What are the antibodies produced by the body that can bind to the exotoxin?
toxoid
What is the altered toxin used to stimulate the immune system?
diphtheria and tetanus
What are some examples of a toxoid?
botulism and staphylococcus food poisoning
What are some examples of disease cause by bacterium exotoxins?
active
In A-B toxins, the A is what part of the exotoxin?
binding
In A-B toxins the B is what part of the exotoxin?
A-B toxins
What kind of toxin inhibits protein synthesis and kills the cell?
membrane-disrupting toxins
What exotoxin causes lysis in the host cell plasma membrane?
Membran-disrupting toxins
What exotoxin makes proteins in the plasma membrane and disrupts the phospholipid layer?
leukocidins and hemolysins
What are some examples of membrane-disrupting toxins?
WBC
The membrane-disrupting toxin leukocidins is a toxin that kills what?
RBC
The membrane-disrupting toxin hemolysins is a toxin that kills what?
superantigens
What is the term for an intense immune response or a super immune response?
Endotoxin
What product produced by bacterium is part of the cell wall, produced by gram negatives only, part of the lipopolysaccharide and is only released when a cell wall is damaged?
pyrogenic reponse
This response is present when a Gram negative cell is ingested by a macrophage, the macrophage degrades bacterium and releases IL-1, IL-1 is carried through the blood vessels to hypothalamus, then the IL-1 causes the hypothalamus to reset at higher temperature?
Septic shock
This condition is due to a loss of blood pressure due to an endotoxin?
septic shock
When a bacterium is ingested by a macrophage, phagocyte produces tumor necrosis factor (TNF-a), and then TNF-a binds to capillaries making them permeable it causes this condition?
death
Septic shock can cause large amounts of fluids to be lost and may even cause what?
LD
Which measure (LD or ID) is used to express virulence of pathogens or toxins?
bacteria
In a biofilm what is the first layer?
biofilm
Dental plague, algae on a pool, and soap scum are all examples of what?
spreading factor (helps move through collagen)
How does the enzyme collgenase help with evasion?
neurotoxin
What exotoxins attack nerve cells?
enterotoxin
What exotoxin attacks GI tract cells?
cardiotoxin
What exotoxin attacks heart cells?