Microbial Control and Virulence, and the Human Immune ... FS/Lectures... · Microbial Control and...

Microbial Control and Virulence, and the Human Immune System

Module 3 Textbook readings:

Microbial Control Chapter 23, Pages 300-310

Definitions 300-310 Scrubbing 301-302 Temperature Control 302-304 UV Light 304 Chemical Control and Variables 305-310

Pathogen Virulence Chapter 24, Pages 314-329

Variables of Disease Transmission 314 Essential Terminology 314-315 Classification of Diseases and Infections 315-318 Characteristics of Pathogenic Bacteria 318-319 Reservoirs 319-320; 322-323 Universal Precautions 320-322 Modes of Transmission 323-329 Portals of Entry 327-329

Human Resistance Chapter 24, Pages 329-334

Resistance: First Line of Defense 329-330 Resistance: Second Line of Defense 331-333 Adaptive Immunity 333-334

Control of Microorganisms, Chapter 23, Pages 300 – 310

1. Essential Definitions / Concepts (Pages 300 – 301)

A. Goals of Importance

i. Disinfection

ii. Preservation

B. Compare and Contrast Levels of Control (Page 301)

Microbiology FS Microbial Control, Virulence, and Human Immune System

i. Sterilization

ii. Disinfection

a. To what is it applied and degrees of effectiveness

iii. Antisepsis

a. To what is it applied and degrees of effectiveness

2. Physical Control Methods (Pages 301 – 304)

A. Define Scrubbing

i. Importance

ii. Compare and contrast Scrubbing and Inanimate Objects and non-living

tissue

a. Embalming and accidental introduction of microorganism into

tissues

B. Temperature (Page 302)

i. Heat and the relationship to proteins

ii. Terms

a. Thermal Death Point

b. Thermal Death Time

c. Decimal Reduction Time

iii. Incineration (Page 302)

iv. Cremation (Page 302)


a. Retort

b. Temperature

v. Moist Heat (Page 303)

a. Boiling

• Limitations: Endospores

* Clostridium botulinum

* Clostridium perfringens

b. Fractional Sterilization Process (Page 303)

c. Steam under Pressure (Page 303)

• 121°C @ 15 psi for 15 minutes

• Autoclave

vi. Cold (Pages 303 - 304)

a. Refrigeration of Human Remains – value and limitations

vii. UV Light (Page 304)

a. How does UV light control microorganisms

C

G

T

A

T

A

T

A

C

G

T

A

C

G

Normal DNA

Damaged DNA

G

C

A

T

A

T

A

T

3'

5'

C

G

T

A

T

A

T

A

C

G

T

A

C

G

G

C

A

T

A

T

A

T

3'

5'

UV LIGHT

DNA damaged by UV light is no longer available to the organism, and can therefore can not survive.


3. Chemical Control Methods (Pages 305 – 310)

A. Introduction (Pajge 305)

B. Some Classifications

• Germicides • Bactericides

• Fungicides • Viricides

• Sporicides • Insecticides

C. Variables to consider when using Chemical Agents of Control

i. Variables that effect antimicrobial agent activity (Pages 305 - 306)

a. Population Size (Page 306)

b. Time

ii. Halogens

a. Chlorine (Pages 306 – 307)

You do not need to know the below, only that Cl2 and H2O react to from Hypochlorites

b. Iodine (Pages 307-308)

• Ticture

Cl2 + + +

+

H2O H+ Cl- HOCl

H+ OCl-HOCl

Chlorine Water Hydrogen Ion

Hydrogen Ion

Chloride ion Hypochlorous Acid

Hypochlorous Acid Hypochlorite Ion

Halogens


• Iodophore (ie, Betadine)

iii. Alcohols (Page 308)

a. How do they work?

b. Limitations

iv. Aldehydes (Pages 308 - 309)


b. Compare and contrast Formalin and Formaldehyde

• Note: Potential Carcinogen (Page 308)

c. Glutaraldehyde (Page 308)

• Effectiveness

• Usage with embalming instruments.

v. Phenolic Compounds (Pages 309 - 310)


b. Cresols as disinfectants

c. Hexachlorophene and embalming (Page 310)

vi. Quaternary Ammonium Compoounds (Page 310)


b. Drawbacks

Microbial Virulence, Chapter 24, Pages 313 – 329

OH

CH3

OH

CH3

OHCH3

Cresols


1. Essential Definitions / Concepts (Pages 313 – 334)

A. Reservoir (Page 314)

B. Portal of Entry

2. Factors that influence Susceptibility (Pages 314 – 315)

A. Virulence

B. Portal of Entry

C. Number of microorganisms

D. Status of Resistance of host

3. Some More Terminology (Page 315)

A. True Pathogen vs Opportunists

B. Exogenous vs Endogenous

C. Communicable Diseases vs. Noncommunicable Diseases

i. Endemic Disease

ii. Epidemic Disease

D. Classification of Infections

Reservsoir is where apathogen survives in nature.

Host may not experience disease

Organism Leaves Reservoir

If host is Suseptible

If host is Not Suseptible

Enters PotentialHost through

“Portal of Entry”


i. By Location

a. Local Infection (ie., boil)

b. Focal Infection (sinus infection)

c. Systemic Infection

ii. By Time or Relationship (Page 316)

a. Primary Infection

b. Secondary Infection

iii. Mixed Infection (Page 316) Example: bite wounds

E. Blood Infections (Pages 316 – 318)

i. Viremia

Highly VirulentOrganism

Attacks Healthyindividual

Less VirulentOrganism

Attacks Weakenedindividual

ImmuneSystemFailure

Healthy individual Weakened individualFurther

Weakened individual

Primary Disease Secondary Disease

Death

Bacteria “A”does not

cause infection

Bacteria “B”does not

cause infection

Bacteria “A” and “B”together

cause infection


ii. Bacteremia

iii. Septicemia

iv. Toxemia

a. Examples (See table 24-1, page 318)

Organims Toxin Disease

Bordetelia pertussis à Pertussis Toxin à Pertussis

Clostridium botulinus à Botulism Toxin à Botulism

Coynebacterium diphtheriae à Diphteria Toxin à Diphteria

v. Classification of Toxins (Pages 318 – 319)

a. endotoxin vs exotoxin

b. Examples:

• Clostridium tetani (endotoxin)

• Staphylococcus aureus (exotoxin)

vi. Classification of Enzymes (Pages 319)

a. What is an enzyme

b. Examples:

• Coagulase catalyzes blood clot production (Page 319)

• Collagenase catalyzes collage break down (Not in text)


vii. Capsule and Endospores

4. Sources of Disease (Page 319 – 320, also Pages 322 - 323)

A. Reservoirs (Pages 319 – 320)

i. Human

ii. Animal

a. Examples

• Salmonella sp. (reservoir: poultry)

• Rabies (reservoir: many mammal species)

A suseptible human(weakened or immunocompromised)

Human is Symptomatic

Transferred through“Portal of Entry”

Healthy Humanmay be reservoir

of disease causing agent.

A strong immune systemkeeps potential pathogen

under control

Human is asymptomatic

Reservsoir is where apathogen survives in nature.

Host may not experience disease

Organism Leaves Reservoir

If host is Suseptible

If host is Not Suseptible

Enters PotentialHost through

“Portal of Entry”


iii. Environment (Example below is of Giardia lamblia)˜

a. Examples

• Endospores of Clostridium botulinum and C. tetanus

• Rabies (reservoir: many mammal species)

• Take note of comment regarding embalming equipment

5. Universal Precautions (Pages 320 – 321) Please take special note of this.

A. What are the importance of Universal Precautions

B. What are the Universal Precautions

6. Disease Transmission (Pages 323 – 327)

A. Direct Transmission

i. Fecal/Oral route

ii. Sexual Transmission

B. Indirect Transmission

i. Fomite

ii. Food Examples

A suseptible human(weakened or immunocompromised)

Human is Symptomatic

Transferred through“Portal of Entry”

Cystsor endospores

cells of pathogen

FomitesFoodFecesWater

Reservoir: Beavers stronglyimplicated. Also, many other wild

animals as well as domestic animals


a. Meat

b. Eggs

iii. Water

iv. Air

a. Mycobacterium tuberculosis

v. Zoonosis

• Example: See handout on Toxoplama Life Cycle

a. Rabies

b. Listeriosis

vi. Zoonotic Diseases and Vectors

a. Define Vector

• Biological Vector

(Example: Deer Tick - See handout on Lyme Disease)

• Mechanical Vector

* Example: Fly


7. Portals of Entry (Pages 327 – 329)

• Define “Portal of Entry”

A. Skin and Mucous Membranes

i. Wounds to Skin

ii. Insect Bites

iii. Animal Bites

iv. Mucous Membranes of Eyes and Mouth

B. Respiratory Track

C. Digestive Track

D. Genitourinary Tract

E. Placenta

7. Portals (or Vehicles) of Exit (Page 329)

8. Resistance to Infection and Disease (Pages 329 - 334)

A. Mechanical / Physical Barriers (Pages 329 – 330)

i. Unbroken Skin

ii. Normal Flora of Skin

iii. pH (Acidification of the skin)

iv. Tears

v. Mucous Membrane of Respiratory Track


B. Physiological Barriers

(Pages 331 – 333)

i. Inflammation

ii. Fever

iii. Phagocytosis by Immune Cells

1

2

3

4

5

6

7

The phagocyte engulfs bacteria (1). The bacteria is now in within the phagocyte (2). Containers of digestive enzymes (3) now fuse with the container containing the bacte-ria (4). Digestive enzymes will now come in contact with bacterial (5) and begin digest-ing it (6). Any waste is released from the phagocyte.

IncreasingBacterial Stress

IncreasingBacterial Stress

BacterialGrowth

Rage

Bacterial Survival Normal

BodyTemperature

Fever

Body Temperature

High

0

Note that as temperature increases with fever, the abiligy of bacteria to survive decreases.


iv. Lysozyme

v. Stomach Acid (Gastric Juice)

vi. Interferon (don’t do)

C. Human Immue System (Pages 333 – 334)

i. Antigens and Antibodies

LYSOZYME

Cell Wall

Cell Membrane

Lysozyme digests bacterial cell wall.Cell membrane now ruptures

Microbial Control and Virulence, and the Human Immune ... FS/Lectures... · Microbial Control and...

Documents

Transcript of Microbial Control and Virulence, and the Human Immune ... FS/Lectures... · Microbial Control and...