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59 Cards in this Set

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Name several ways (5) phagocytes may fail to remove/eliminate the infectious agents
1. Inhibits opsonization/chemostaxis -> kills phagocytic cells
2. Inhibits phagocytosis; prevents uptake of these cells
3. Once inside, prevents lysosomal fussions
4. Escape lysosome & grow in cytoplasm
5. Resist antibacterial lysosomal action & multiply within cell -> block activation by interferon-gamma
Name several exotoxins (4) and discuss their mode of action
1. C. diphtheria -> disrupts protein synthesis, causing cell death
2. C. tetani -> blocks inhibitory NT release; continuous excitatory NT stimulation
3. C. botulinum -> prevents release of excitatory NT so stimulation of muscle is blocked
4. V. cholerae -> increases cAMP; causes inhibition of absorption of elements (water & ions), producing watery stool
Koch’s postulates: its uses (4)
1) Observation
2) Isolation in Pure Culture to separate microbe
3) Re-Infection in healthy people
4) Re-Observation to see is disease is present in newly infected people. Re-isolation in pure culture.
Koch’s postulates: its exceptions
NOT used for (3)
-Mycobacterium leprae (leprosy) b/c of slow growth so cannot be isolated.
-Treponemma Paillidum(syphilis) b/c needs human tissue to grow.
- Polymicrobic infections, causing same disease.
What are the significance of LD50 and ID50?
LD50 stands for LETHAL DOSE. It means how many microbes kill ½ people that get it.
ID50 stands for INFECTIOUS DOSE. How many microbes bring down ½ people that come in contact with it.
The lower the number, means the more virulent it is. More virulent means more efficient organism is.
T/F
The lower the LD50 and ID50 the more virulent the organism is.
True
Differentiate between, pili, fimbrae, cilia, lipoteichoic acid and adhesions.
- Pili - short appendages used to transfer DNA from one cell to another; highly specific, promotes adhesion & blood clotting, prevents phagocytosis
- Fimbrae – short appendages used to adhere to surfaces
- Cilia remove microorganisms by propelling motion
- Lipoteichoic acid – in gram positive only
- Adhesions – general binding to target; can be pili, fimbrae, lipoteichoic acid, glycocalyx, and adherence proteins
The function of "mucociliary elevators" is to:
A. Remove microorganisms from the lower respiratory tract
B. Remove microorganisms from the gastrointestinal tract
C. Kill microorganisms
D. Remove microorganisms from internal cavities
The function of "mucociliary elevators" is to:
A. Remove microorganisms from the lower respiratory tract
Discuss the formation and significance of biofilm and colonization. Also note on quorum sensing.
Biofilm allows organisms to stick together which promotes colonization in other parts of body. Like a cell adhesion.
Quorum Sensing is when a lot of bacteria attach and encourage other bacteria to join which promotes growth.
Compare and contrast: endotoxin, exotoxins, enterotoxins, neurotoxins, and cytotoxins
Endotoxin-is a structural component of bacteria that is released when they die; part of Gram negative structure Ex: LPS
Exotoxin - excreted by a microorganism; dimeric molecules, made of 2 components (one allows attachment, other is functional);
Enterotoxin- requires entry of cell. Is a toxin released in the Intestines. They are frequently cytotoxic…B needed for entry into cell; A needed for toxin activity
Neurotoxin-affects normal nerve cell function
Cytolytic toxins- attack surfaces
Exotoxins are...(3)
-highly toxic
-nonpyrogenic
-highly immunogenic
Endotoxins are...(3)
-weakly toxic
-pyrogenic
-weakly immunogenic
What is a superantigen?
Produced by some bacteria, they Overactivate Tcells by non-specific binding so results in excess of cytokines which leads to damage.
Which of the following is true of endotoxins
1. They are integral parts of Gram-negative outer membrane
2. They are heat resistant
3. They may stimulate macrophages to secret cytokine
4. All are correct
Which of the following is true of endotoxins
4. All are correct
Exotoxins:
1. Are usually made of protein.
2. Always kill the host cell
3. Are made only by gram-positive bacteria
4. Are always enzymes
5. None of the options are correct
Exotoxins:
1. Are usually made of protein.
Which of the following could be administered as vaccine?
1. Toxoid
2. Antitoxin
3. Enterotoxin
4. Exotoxins
Which of the following could be administered as vaccine?
1. Toxoid
Diphtheria toxin is an exotoxin produced by Corynebacterium diphtheriae.
It enters the cells and:
1. Causes the cells to lose their ability to make protein
2. Interferes with nerve-muscle communication
3. Interferes with cell division and binary fission
4. Causes cells to lose electrolytes into environment of intestine
Diphtheria toxin is an exotoxin produced by Corynebacterium diphtheriae.
It enters the cells and:
1. Causes the cells to lose their ability to make protein
The paralysis in tetanus is due to a neurotoxin that
1. inhibits the release of a neurotransmitter needed to relax muscles and cause rigid paralysis
2. Acts in the brain to cause excess muscle contraction.
3. Interferes with synaptic transmission and causes placid paralysis
4. Acts exclusively on the respiratory musculature.
5. Inhibits protein synthesis in heart muscle.
The paralysis in tetanus is due to a neurotoxin that
1. inhibits the release of a neurotransmitter needed to relax muscles and cause rigid paralysis
Which of the following is an enterotoxin
1. Botulin toxin
2. Tetanus toxin
3. Cholera toxin
4. Lipopolysaccharide
5. Diphtheria toxin
Which of the following is an enterotoxin
3. Cholera toxin
Some antigens are considered "super antigens" because they:
1. They are active in low concentrations because they are neurotoxins
2. Over stimulate the host immune system in a non-specific manner
3. They can invade and kill many different eucaryotic cell types
4. They inhibit protein synthesis in susceptible cells, causing cell death.
5. They inhibit DNA synthesis in susceptible cells, causing cell death.
Some antigens are considered "super antigens" because they:
2. Over stimulate the host immune system in a non-specific manner
Disseminated intravascular coagulation (DIC) or shock may result from
exposure to:
1. Cytolytic toxins
2. Neurotoxins
3. Leukocidins
4. Endotoxin
Disseminated intravascular coagulation (DIC) or shock may result from
exposure to:
4. Endotoxin
The major function of bacterial capsules in virulence is to:
1. Inhibit phagocytosis
2. Act as a permeability barrier to toxic factors and antibiotics
3. Retain the rigidity of the cell
4. Serve as an adhesin
5. Protect the spore
The major function of bacterial capsules in virulence is to:
1. Inhibit phagocytosis
What is the significance of normal flora?
They are organisms associated with healthy body tissues.
Skin has Staphylococcus Corynebacterium.
Teeth has Streptococcus mutans.
Small Intestine has Lactobacilli. Upper Resp. Tract has Staph, Strep.
Urethra has E.coli & Proteus Vagina has Lactobacilli.
Many virulence factors are enzymes that degrade or otherwise harm host
tissue. Which of the following destroys white blood cell?
1. Hyaluronidase
2. Hemolysins
3. Leukocidines
4. Streptokinases
5. Collagenase
Many virulence factors are enzymes that degrade or otherwise harm host
tissue. Which of the following destroys white blood cell?
3. Leukocidines
The normal flora:
1. Never causes disease, by definition
2. Has no biological function other than to make culture of pathogens more difficult.
3. Is restricted to the gastrointestinal and urogenital tracts
4. Consists of bacteria found frequently on or in healthy people
5. All options are correct
The normal flora:
4. Consists of bacteria found frequently on or in healthy people
Name ways bacteria may evade immune system (8)
1) Fast in/out
2) Remaining inside a host cell
3) Infecting “privileged sites” like nerve sites
4) Mimicking host antigens
5) Binding host Ab “upside down” (Fc portion so it would be unusable)
6) Antigenic variation-confuses humoral response
7) Actively suppressing immune system
8) Capsules prevent phagocytosis
What are the prevalent infectious diseases in the US? 3
-Upper respiratory disease
-Gastroenteritis
-STD
What are the prevalent infectious diseases in developing countries?
-Intestinal- rotaviruses, salmonella, camphylobacter
-Respiratory diseases
-AIDS
-Diseases caused by lack of immunization - tetanus
Name the three incidents over the last century that brought infectious diseases under control. List the disease controlled by each incidence.
Chlorine to treat the water.-reduced cholera and typhoid fever.
First use of Penicillin.-pneumonia
Passage of Vaccination Assistance Act.- smallpox eradicated.
Nosocomial infections; definition, causative agents, contributing factors
Nosocomial-associated with a stay in the hospital b/c of weakened immune system contributes.
Can be caused by breakdown of barriers. (Burns, catheters,surgery,endoscopy,chemo.)
Antibiotic resistant bacteria is known to live in hospitals.
1/20 patients infected. 1/400 deaths. Very High #.
Crowding increases risk.
Pathogen is...
bacteria capable of causing a disease.
Disease is...
abnormal condition or function
Infection is...
Infection-Is the growth of a microbe within a host. May be asymptomatic or cause disease.
Virulence is...
Virulence-relative ability to cause disease. The more virulent means more harm it can do.
Opportunistic Pathogen is...
Opportunistic Pathogen- a pathogen that USUALLY does not cause disease in a healthy person. If immune-compromised pathogen has chance to infect.
Compare and contrast invasive vs. non-invasive infections
A non-invasive infection is highly toxic. It doesn’t grow much. Ex: food born toxins, Clostridium Botulinum & Staphylococcus Aureus.
Invasive infection produces little or no toxin. Ex: Shigella strains & TB. This type does damage by spreading.
Give examples of and describe the mode of action of enzymes that facilitate invasion by bacteria (7)
1. Hyaluronidase allows bact. To spread easier
2. Collagenase dissolves collagen to allow bact to spread easier
3. Streptokinase kills both RBC & WBC; also allow easy bact spreading
4. Coagulase clots around microbes, isolating from rest of body
5. Hemolysins kill RBC
6. Leukocidins kill WBC
7. Streptolysin kills WBC, platelets, RBC.
Significance of capsule, its role in pathogenicity, and what happens if a cell loses its capsule?
Capsule is considered a virulence factor and is the cause of some disease. It helps protect bacteria against phagocytosis and from dessication. They may also help the organism adhere.
What are the routes of entry for infectious diseases, what is meant by parentral route? Vector transmission?
Vector transmission is through an insect bite, carries disease from one host to another. Parentral route means the transmissions is through piercing of the skin or mucous membranes.
Famous Microbiologists and their achievements
Leeuwenhoek?
-first microbiologist
Famous Microbiologists and their achievements
Hooke
-first to see and define microbes, cells
Famous Microbiologists and their achievements
Koch-
his postulates on microbes and diseases
Famous Microbiologists and their achievements
Jenner-
discovered immunization, smallpox
Famous Microbiologists and their achievements
Fleming
Fleming-penicillin
Famous Microbiologists and their achievements
Ehrlich
Ehrlich-magic bullet, salvarsan-syphilis
Famous Microbiologists and their achievements
Pasteur
Pasteur - fermentation, pastereurization, “father”
Famous Microbiologists and their achievements
Senelweiss
Senelweiss-aseptic technique
Know the kingdoms in the five-kingdom system. Where viruses stand in this system
5 kingdoms: fungi, plants, animals, protozoans, monera
Viruses are not in kingdoms or domains, not officially a microbe.
Relative sizes of microorganisms
0.5-2.0 microns (RBC is 7.5 mi) Eukaryote of 20mi=BIG
What was the magic bullet?
Effectively targeting a bacteria without affecting other organism. Associated with Ehrlich and his syphilis research.
What are the major bioelements (6)
C, O,N, H, S, P
Components of cell wall and cell membrane in both Gram + and - cells.
Gram(+)Techoic Acid. Has thicker cell wall.
Gram(-)LPS, an endotoxin that is released when bacteria dies. Porin Proteins that make it more resistant to entry. Thinner cell wall.
What is an amphipathic molecule?
A molecule containing both hydrophobic (FA) and hydrophilic (glycerol) group.
What are examples of monomers/polymers you may find in the cell. (4)
1. Sugars/polysaccharides
2. FA/lipids
3. Nucleotide bases/nucleic acids
4. AA/proteins
Loss of electron means ______
oxidation
Gain of electron means ______
reduction
Know shapes of the bacteria.
Cocci (round) Bacilli( rods) Spirillum (curved rods) Spirochete (squiggly line
What Peptidoglycan is made of?
Large polymer of N-acetyl glucosamine and N-acetyl muramic acid. It is the main structural component of bacteria cell walls. It is found only in prokaryotes. And is more prevalent in Gram+ bacteria.
What is considered an endotoxin?
Substance in bacteria that is released when they die. LPS is the example from Gram (-) bacteria.