What are the 4 determinants for infection? - Where applicable indicate if these pertain to innate or adaptive immune system

1. Number of Microorganisms - Depends on your exposure 2. Virulence of Microbe - fewer needed for disease if they're extremely virulent 3. Host immune status - INNATE response 4. Past immune history - ACQUIRED response

Respiratory - most common infection type - ability to control

- Viral Infection = most common - Hard to control airborne pathogens

Vectorborne/animal borne illnesses - how are they contracted? - Which is most common? - Eradication?

- Contracted via Direct Animal Contact - MORE OFTEN contracted from arthropod like a mosquito or tick - These types of pathogens are hard to irradicate

(04) Microbial Pathogenesis Flashcards by Barrett Thompson

Define Pathogen

A microbe capable of causing disease especially in immunocompetent people

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Pathogenesis

The mechanism of disease developement

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Virulence

a measure of a microbe’s ability to cause disease

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Virulence Factor

any number of products produced by pathogens that allow the microbe to invade, evade host defenses, and/or cause disease

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**Differentiate colonization from infection

Colonization - Presence and multipication of microorganisms WITHOUT tissue invasion or damage

Infection - colonization that leads to disease

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Define Epidemic

a disease that rapidly affects many people in a fixed period of time

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Define Pandemic

a disease that affects people worldwide

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Define Endemic

Disease that is constantly present at low levels in a specific population

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What are Primary Pathogens?

- synonymous term?

Pathogens that are ALWAYS associated with disease

Synonym = Frank Pathogens

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What are Opportunistic pathogens?

- virulence?

Pathogens that are ONLY a problem for immunodeficient people

Typically lower virulence

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In terms of Primary Pathogens and Opportunistic Pathogens, where do most pathogens fall?

Somewhere in between

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*What are the 4 determinants for infection?

- Where applicable indicate if these pertain to innate or adaptive immune system

Number of Microorganisms
- Depends on your exposure
Virulence of Microbe
- fewer needed for disease if they’re extremely virulent
Host immune status
- INNATE response
Past immune history
- ACQUIRED response

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What are the stages of bacterial pathogenesis?

Transmission
Evasion of Host Defenses
Adherence
Colonization
Spread
Symptoms produced by toxin production or invasion and inflammation
Host Response
Progression or Resolution

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What is the incubation period?

- what 5 stages or pathogenesis are within the incubation period?

Incubation Period - time period before symptoms are expressed

5 steps during Incubation:

Transmission
Evasion of Defenses
Adherence
Colonization
Spread

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What are the 2 general type of symptoms a patient may experience?

Prodomal (non-specific)

2. Specific

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What are the most common routes of infection?

Respiratory
GI (Fecal-oral)
Blood-Borne
Sexual
Maternal-Fetal or Neonatal
Vector- or animal-borne
Fomites, Soil, Water

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Respiratory

most common infection type
ability to control

Viral Infection = most common

- Hard to control airborne pathogens

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GI (fecal oral)

- ability to control

Well controlled in 1st world countries

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Blood-Borne

- how do these infections typically arise

IV drug use and Transfusions

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Maternal-Fetal or Neonatal Infections

- occur where?

Infections occuring in utero or perinatal (at the time of delivery)

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Vectorborne/animal borne illnesses

how are they contracted?
Which is most common?
Eradication?

Study These Flashcards

Contracted via Direct Animal Contact
MORE OFTEN contracted from arthropod like a mosquito or tick
These types of pathogens are hard to irradicate

What are the 3 most common portals of entry?

- what do these have in common

Study These Flashcards

Respiratory Tract
GI tract
GU tract

**These are areas where the skin and mucous membranes meet

What are some of the defenses of the Respiratory Tract?

Study These Flashcards

Nasal Turbinates, oropharynx, larynx
Ciliary Epithelia of Lower resp. tract
Mucus, sIgA, Lysozyme, Lactoferrin
Alveolar Macrophages
Upper respiratory tract normal flora

What are some of the defenses of the GI tract?

Study These Flashcards

Stomach acid, Bile
Peristalsis
GALT
Lysozyme, sIgA, Mucus, Lactoferrin
Normal LOWER GI flora

What are some of the defenses of the Genital tract?

1. Low pH 2. Mucus, sIgA, Lysozyme, lactoferrin 3. Normal Flora

What are some defenses of the Urinary tract?

1. Mechanical Flushing 2. sIgA 3. Low pH

What mechanism (virulence factor) counters mechanical flushing in the Urinary Tract?

- Ability to Adhere (through pili, etc)

Obligate Intracellular Pathogens | - problem with isolating?

They usually cannot be cultured for a clinical Dx

What are facultative Intracellular Pathogens?

- Grow on Medium but KEY ASPECT of pathogenesis is Hi-jacking a cell **Hiding in macrophages etc.

what does the Type III secretion system have to do with Receptor mediated endocytosis?

- Bacteria that want to become intracellular may inject its own receptor into the host cell so that it can bind and enter the cell

Transcytosis - what is it? - e.g. of what does it?

- Bacteria moves through a cell to enter a new space | - Shigella can travel from gut lumen through M Cell into subepithelial space

3 common ways to prevent receptor mediated endocytosis?

- Prevent Fusion with Phagosome - Prevent Phagosome fusion with lysosome - Prevent acidfication by lysosome

What does it mean if an infection disseminates? - how can it do this? - what is a likely cause of distal disemination?

- Spreads throughout the body via: - Blood - Lymph - CSF **Toxin dissemination WITHOUT bacterial spread

What are 5 non-toxin virulence factors associated with spread and survival of pathogens?

1. Capsule 2. Collagenase and Hyaluronidase 3. Coagulase 4. IgA protease 5. Protein A

Capsule - virulence action - how can it be countered - common bacteria with it? - Disease associated with these bacteria?

- Antiphagocytic - Countered by VACCINE-DERIVED antibodies Commonly in: - S. pneumoniae - H. influenzae - N. Meningitidis **Commonly associated with meningitidis

Collagenase and Hyaluronidase - virulence action - associated bacteria

- Allow permeation through subcutaneous tissue | - Skin associated bacteria (usually staph)

Coagulase - virulence action - associated bacteria

- Causes blood clot which prevents macrophages from accessing pathogen - Staph aureus

IgA Protease - most active where? - Cleaves where? - associated bacteria

- Most active on MUCOUS surfaces because its IgA - Cleaves at the Hinge Region Associated Bacteria: 1. S. pneumoniae 2. H. influenzae 3. N. gonorrheae

Protein A - Virulence Action - Associated Bacteria

- Binds to IgG Fc thus preventing the action of the complement - Staph Aureus associated

What are the 2 types of inflammation? | - associated cells?

1. Pyogenic (pus-producing) - Neutrophils | 2. Granulomatous - Macrophage

Where do most of our symptoms that arise from viruses come from?

- Our own immune response

* *What are the 3 hallmarks of sepsis? | - what causes sepsis?

1. Low Blood Pressure 2. Fever 3. Coagulation - Caused by LPS (gram -) or Lipoteichoic acid (gram +)

Exotoxins - made of? - Beneficial Uses?

- Peptides | - Antigenic so inactivated forms (toxoids) can be used for immunization by inducing antibodies

What are 4 types of Exotoxins?

1. A-B Exotoxins 2. Metalloproteases 3. Pore-forming toxins 4. Superantigens

A-B Exotoxins - composition - how do they work? - examples?

Composition: 1. A subunit - active toxic subunit 2. B subunits - Binds the toxin to the target ``` How: 1. ADP-ribosylation of G proteins (most common) 2. Alter ribosomes 3. Inhibit protein synthesis ``` examples: - Diphtheria Toxin - Cholera Toxin

Metalloproteases - how do they work? - Examples

- Cleave snares blocking neurotransmitter delivery Examples: - botulism - flaccid - tetanus - rigor

Superantigens - how do they work? - associated bacteria?

- Bind to MHC II on APCs results in cytokine storm by T-cells Bacteria: 1. Staph aureus 2. Group A Streptococci

T or F: many resolved infections lead to life-long immunity

True

What are 3 general types of unresolved infections?

1. Recurrent Infections 2. Persistent Infections 3. Cancer

What are 3 reasons why a patient would have recurrent infections?

1. Poor Immune Response (incomplete irradication) 2. Antigenic Variation (gonorrhea - pili) 3. Many serotypes

What are 2 reasons for persistent infections? | aka ones that go away and come back

1. Chronic Infections | 2. Latent Infections (e.g. herpes)

What are some cancer causing bacteria and viruses?

Bacteria: - H pylori Viruses: - HPV, HBV, HCV, EBV, KSHV, HTLV-1

(04) Microbial Pathogenesis Flashcards

(52 cards)