Micro3. Chap 19
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- Some bacteria have _________ relationships with their hosts. The three types of these relationships are:
-
Symbiotic
1. Mutualism (both benefit, ex. K and B vitamins)
2. Commensalism (bacteria benefit with no harm to the host)
3. microbe grows at the expense of its host. - The _______ ________ are those bacteria that are commonly found on/in the body of a healthy host.
- Normal flora
-
True or False:
Our bodies have more bacterial cells in them then human cells, so we are technically more bacteria then human. - True
- many of the normal flora play ________ protective roles for the host.
- Critical
- ___________ ________ causes scalded skin syndrome when staph epi is compromised on the skin (staph epi is a normal flora). The example in class involved iodined babies in ______'s.
-
Staphylococcus aureus
1950's - _________ __________ is allowed to grow out of control in the GI tract during aggressive antibiotic therapy.
- Clostridium difficile
- Staph epi is found in the ________ and _________.
- Nose and skin.
- Infection is ___________ colonization by a microbe.
- Parasitic
- Clinical manifestations are either __________ (apathogenic) or _________ (pathogenic).
-
-Subclinical (w/o pathology it's not parasitic)
-Clinical (symptoms of disease, you feel sick) - Their are two main courses for infection, they are:
-
1. Primary- disease caused by the initial infection
2. Secondary- because of the initial infection, another microbe can establish an infection. - An example of a secondary course of infection is ________ virus being followed by ___________ __________ pneumonia.
-
Influenza
Klebsiella pneumonia - Pathogenicity is the capacity for a microbe to ________ _________.
- Cause disease
- Some microbes are __________ pathogens and usually cause disease after colonization. Others are ____________ pathogens and cause disease only in __________ with some other unusual events (like Immunocompromised people ((ex _____)) and compromised normal
-
Primary
Opportunistic
Conjugation
HIV - ___________ or contagious diseases are readily transmitted person-to-person (influenza, pertussis and _________)
-
Communicable
Measles - Other diseases are not communicable/contagious (______ ______, ________) since they are not transmitted person-to-person.
-
West Nile
Anthrax - Infection is also a function of __________ of microbes.
- Quantity
- The infectious disease dose is expressed as ______.
- ID50(subscript)
- The ID50 for a microbe is the number of bacteria or viruses needed to infect ___ of ____ people given the dose.
- 50 of 100
- The ID50 varies amoung pathogens. Anthrax is ________.
- 10,000
- List the three courses of an infection:
-
1. Incubation period (no symptoms)
2. Illness- phase of disease
3. Convalescence- recovery from disease - Some people can be ________ for a disease (the example given in class was typhoid Mary)
- Carriers
- List the three duration times for a disease:
-
1. Acute- rapid onset, short duration
2. Chronic- slow onset, long duration
3. Latent- agent is never eliminated - _____ ___ is the most burdonsome latent infection today. It's so widespread in the US because of _______ _____________.
-
Hep C
Blood Transfusions - Most pathogens are _________ to a specific tissue, others can be _________, and some __________ pathogens can become _________.
-
Localized
Systemic
Localized can become systemic - Since a pathogen can become systemic, the distribution of a pathogen is often a ________ __________ indicator.
- Poor prognostic
- Name the four main types of microbes and their products in the blood:
-
1. Bacterermia- Bacteria in blood
2. Viremia- Virus in the blood
3. Toxemia- Toxins in the blood
4. Septicemia- life-threatening; bacteria replicating in the blood - The most serious of the four main types of microbes and its toxins is _________.
- Septicemia
- Etiology is the study of the _________ and ________ of disease.
- Causes and origins
- _______ postulates of infectious disease etiology.
- Koch's
-
Koch's Postulates:
1. The microbe must be _______ in every instance of the disease. - Present
-
Koch's Postulates:
2. The microbe must be __________ and _________ from a diseased animal. - Isolated and cultured
-
Koch's Postulates:
3. Introduction of the microbe into a _________ ________ must result in disease. - Susceptible animal (like the example of anthrax in cows and chickens)
-
Koch's Postulates:
4. The microbe must be ___________ from the animal. - Reisolated (to make sure it's in there)
- List five diseases that are only susceptible in humans:
-
1. HIV
2. Measles
3. Mumps
4. Smallpox
5. Hanta virus - The _________ __________ or gene must be detected in pathogenic members of a species but not in nonpathogenic members.
- Virulence factor
- Introduction of the gene(s) that encodes the virulence factor into a __________ must convert the microbe into a pathogenic strain.
- Nonpathogen
- The gene must be __________ when introduced into a susceptible animal. To detect this, you look for _______.
-
Expressed
mRNA - _________ or immune cells (e.g. Tc cells) must protect the animal from the disease.
- Antibodies
-
There are four main mechanisms for disease:
1. Production of ________ that are ingested.
2. ___________ of the host surface (skin or mucosa), followed by _________ production
3. _________ of host tissues
4. Invasion of host tissues, f -
Exotoxins
Colonization, exotoxin
Invasion
Exotoxin -
Establishment of infection:
__________ is mediated by glycoproteins termed ________. Typically that have ____________ for host cell surface proteins. -
Adherence
Adhesins
Specificity -
Establishment of infection:
___________ is the replication of bacteria at the site of adherence. - Colonization
- Colonizing microbes secrete factors that _______ the host cell response, such as _____ ___________ (enzymes that digest IgA dimers)
-
Impair
IgA proteases - Colonization also allows for the expression of _______-binding molecules termed __________.
-
Iron
Siderophores -
Establishment of infection:
Delivery of _________ molecules into host cells, often ___________ ________ that damage the host cell. -
Effector
Virulence factors - ____________ _________ are clusters of genes that encode virulence factors.
- Pathogenicity islands
-
Invasion:
Penetration of the skin happens in two ways: -
1. Cuts, abrasions, burns
2. A vector (flea, tick, etc) -
Invasion:
Penetration of the mucous membranes. This is ________ uptake by cells. Exploitation of __________ __________ by immune cells (they travel using the immune system). -
Directed uptake
Antigen sampling (dendritic cells and macrophages) - ___________ cells rarely get infected with bacteria because they eat things via ___________.
-
Dendritic
Pinocytosis -
Avoiding the host's response:
Hiding within a host cells allows the bug to ________ _________, which are only located in the extracellular matrix. - Avoid antibodies
-
Avoiding the host's response:
Some bugs avoid getting killed by complement ________ _________. An example of this is _________ gonorrhoeae inactivating the C3b complement protein, messing up everything ________ in that pathway. -
System proteins
Neisseria
Downstream -
Avoiding the host's response:
Some bugs avoid death by phagocytes: _________ ___________ kills macrophages. - Bacillus anthracis
- ____________ __________ produces streptolysin O that damages phagocytic cell membranes.
- Streptococcus pyogenes
- ___________ capsules are resistant to phagocytosis.
- Polysaccharide
- Strep pyogenes (protein G) and _______ _________ (protein A) secrete proteins that bind to ____ portions of antibodies, thus neutralizing them.
-
Staph aureus
Fc portions - Exotoxins are proteins secreted by various pathogenic ___________. They can be local or __________.
-
Bacteria
Systemic - Exotoxins can be _________ in small amounts (1g of __________ toxin is enough to kill Earth's population)
-
Fatal
Botulinum - Humans cannot react quickly enough. These exotoxins exert their effect before ________ can be _____________.
-
Antibodies
Synthesized -
Exotoxins:
A-B toxins refer to two polypeptides, A is _________ while B _________ _________. -
Toxic
Dictates target -
Exotoxins:
With ________-damaging toxins, ___________ disrupts RBC membranes. -
Membrane
Hemolysin -
Exotoxins:
__________ "trick" large numbers of helper T cells into producting inflammatory __________ (responding to the wrong infection). -
Superantigens
Cytokines - Without their _________, the bacteria would not be ___________ (or would have little effect).
-
Exotoxins
Pathogenic - ___________ are lipopolysaccharides (LPS). The two components are _______ A (toxic) and a polysaccharide.
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Endotoxins
Lipid - Normally endotoxins are found as an ________ membrane component of Gram___ bacteria.
-
Outer
Negative - Endotoxins bind to ____-______ receptors on phagocytic cells, which results in the release of _________ __________ factor from the cell.
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Toll-like
Tumor necrosis - TNF causes _______ leakage and inflammation. This can lead to ___________ and disseminated ___________ ____________ (AKA septic shock)
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Capillary
Hypotension
Intravascular coagulation -
True or False:
Viruses encode toxins. - False
- Viruses principal cause of damage is...
- death of a cell
- In some viral infections, the immune response is so aggressive that it causes ____________.
- Immunopathology
- Many viruses encode ________-__________ proteins that overthrow the immune response.
- Immune-modulating
- Immune-modulating proteins shut down _____ class I processing and presentation, impair the _________ pathway, viral _________ and interfere with _________ (death signals from T and NK cells)
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MHC
Interferon
Cytokines
Apoptosis