Pathology:

Infections:

1) Disease: abnormal state in which the body isn't capable of carrying on it's normal function

2) Infection: invasion or colonization of the body by pathogenic microbes

3) Pathogens: disease causing microbes (Pathology-study of disease)

4) Etiology: study of disease

Pathology:

Normal Flora: Commensals(Neither harm or benefit the carrying host)

Location: skin, mouth, L.I., URT (nose/throat), eyes (conjuctiva), and urinary and genital tract

 Location and concentration are important bc:

~Antibodies to the normal flora exist in our bodies, but at lower concentrations than would exist for pathogenic bacteria.

Pathology:

Severity or Duration of a Disease:

1) Acute: disease develops rapidly, but last a short time

2) Chronic: disease develops slowly, bodies rxs are less severe, and disease process is likely to be continual or recurrent for a long time

3) Subacute: disease that is intermediate between acute & chronic

4) Latent: causative agent remains inactive for a period of time, but then becomes active

Types of Infections:

Localized and Generalized or Systemic

1) Localized: Microbes limited to an area, like boils or abscessess

 
2) Generalized or Systemic: Microbes or products spread via the blood & lymphatic system

Types of Infections:
Nosocomial~ Hospital acquired

• CDC estimates 5-15% of all hospital patients will acquire a noscomial infection

• Rate of such infections has increased 36% over last 20yrs

• In US, 2M ppl will contract; 20,000 ppl die yearly

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  Types of infections= UTI's, surigcal sites, & Lower RT

         Types of microbes = E.Coli, Staph/Stept., Pseudomonas

Types of Infections:

Bacterium, Septicemia, Toxemia, Viremia, Pyemia

1. Bacterium: bacteria in the blood
2. Septicemia: bacteria multiplying in blood
3. Toxemia: toxins in the blood (tetanus)
4. Viremia: viruses in blood
5. Pyemia: pus forming microbes in blood

     Signs: Measured               Symptom: how pt. feels

1. Period of Incubation
2. Prodromal Syndrome
3. Period of Invasion
4. Acme or Fastigium (# of microbes aren't increasing)
5. Period of Decline (immune sys. or antibiotics, sympts decrea.)
6. Period of Convalescence or recover

Emerging Infectious Diseases:

• New or changing diseases
• Examples: HIV, HCV, E. Coli 0157;H7, Ebola, Coccidiomycosis
• Why~ Jump species, ecological changes, antibiotic resistance, Increase in population, changes in pathogenicity, air travel or migration, changes in host susceptibility, & societal changes

Spread of Infection:

Non-communicable Diseases

• Is not spread from one host to another
  
  
• Caused by: microorganisms that normally inhabit the body and only occasionally produce disease or by microorg. that reside outside the body and produce disease only when introduced into the body. ex: Tetanus via abrasion/wound

Spread of Infection:

Communicable Diseases

1. Contact Transmission: the spread of an agent of disease by direct contact (person-person), indirect contact (non-living object), or droplet transmission (mucus droplets)
   
   

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2. Vehicle Transmission: trans. of disease agents by a medium, such as water (contamations in H2O) , food (food poisioning or tapeworm), or air(sneezing, coughing)

Spread of Infection:

Communicable Diseases (contin.)

1. Arthropod Vectors: animals that carry pathogens from one host to another by mechanical trans. (insects parts) or biological trans. (ingests infectious blood)
   
   
2. Animals or Zoonoses: diseases that occur from wild/domestic animals and can be transmitted to humans (Zoonoses)
   
   
3. Human Carriers: many ppl harbor pathogens and transmit them directly or indirectly to others, ppl with signs and sympts of a disease may transmit, also ppl harbor pathogens and transmits them to others w/o exhibiting any signs of illness.

Host Parasite Relationships:

• Symbiosis: 2 parties living together and both benefit
  
  
• Commensalism:the living together of two organisms in a relationship that is beneficial to one and has no effect on the other (ex: normal flora)
  
  
• Parasitism: 1 benefits, 1 party is harmed (ex: tapeworm)

Intrusion of Microbes:

Portals of Entry

1. Respiratory Tract
2. Gastrointestional Tract
3. Skin: mainly breaks in the skin
4. Parenteral:depoisted directly into the tisue beneath the skin/mucous membranes (tetanus, injections)
5. Genitourinary Tract: STD's & STI's
6. Placental

Intrusion of Microbes:

How Microbes Cause Disease~ Invasive

1) Physiological Features: pilli, flagella, capsule, CW M protein which helps microbe attach to host & resist WBC's (pyogenes)

2) Exoenzyme Production:

Hemolysins- breakdown of RBC

Leukocidins- destroys WBC

Coagulase- coagulates the blood protein fibriogen to produce fibrin blood clots. Produced by pathogenic staph.

Exoenzyme Production: contin.

Kinase- enzymes that dissolves blood clots (Steptokinase/staphlokinase)

Hyaluronidase- "spreading factor", hyaluronic acid to increase tissue permeability *tissue blackening*, prod. by Clostridium sp.

Immunoglobulin A Proteases- enzymes that digest IgA, bacterial escape= mucousal defense, prod. by H. influenzae & S. pneumoniae

Production of Toxins-

Exotoxins Characteristics:

Produced by: Gram + & - bacteria (cytoplasm)

Produced when: cells are growing and released when cell dies

Heat labile protein: can break down

ex: -Exotoxin *heated* toxoid, then vaccine to make Ab, prevent diseases

-Toxoid given to animals will make antitoxin, tx diseases

Production of Toxins-

Exotoxins Characteristics: contin.

- Lethal Doses: small

- Toxoids and antitoxins producted

- Mode of action- inhibits cell activity

- Destroys specific cells or tissues:

~ Nerve tissue= neurotoxins

~ Intestinal tissue= enterotoxins

~ Heart muscle= cardiotoxins

~ Kidneys= renaltoxins

Exotoxin Examples:

Diptheria: cytotoxin produced by Cornybacterium diphtheriae
- Damages heart tissue and nerve cells

- Vaccine to prevent disease, antitoxin to treat

Scarlet Fever: erythrogenic produced by Streptococcus pyogens

- Red Skin Rash

Botulism: exotoxin of Clostridium botulinum, neurotox= prevents release of acetylcholine -Paralysis and loss of muscle tone Treatment: Antitoxin -Fatal food poisioning

Exotoxin Examples: continued

Cholera: enterotoxin of Vibrio Cholera

- Toxin stimulates the secretion of fluids and electrolytes from small intestines resulting in severe dehydration

- Bacteria do not invade tissue

Tetanus or Lockjaw: neurotoxin produced by Clostridium tetani

- Toxin (tetanospasmin) causes- uncontrolable skeletal muscle contractions

- Vaccines to prevent (DTAP) & Antitoxin to treat

Endotoxin Characteristics:

Produced by: Gram NEG. bacteria only

Produced when: cells die

~Heat stabile lipopolysaccharide protein

~No toxoid or antitoxins

Endotoxin Characteristics:

- Lethal dose larger than exotoxins

Mode of Action- effect non-specific tissue

- Release "fever inducing substances" from neutrophils

- Activation of blood clotting proteins that causes blood clots to obstruct capillaries resulting in tissue death (Disseminated Intravascular Clotting Disease= DIC)

Can lead to: shock and death

Endotoxin Examples:

- Typhoid Fever

- Meningococcal meningitis

Can be treated by: Antibiotics to release more endotoxins or Treat symptoms until endotoxin breaks down

Control of Microorganisms in food include these methods:

1) Pasteurization
2) Freezing & Refrigeration
3) Radiation
4) Canning

5) Chemicals

6) High Osmotic Pressure

7) Drying and Dessication

Pasteurization:

• Mechanism of Action: protein denatures
  
  

• Use: heat treatment for milk that kills all pathogens and most non-pathogens

Freezing & Refrigeration:

• Mechanism of Action: Freezing & Refrigeration = decrease chemical reactions and poss. change in proteins
  
  

• Use:Effective method for preserving microbial cultures, in which cultures are quickly frozen

Radiation:

• Mechanism of Action: Ionizing= Destruction of DNA,

                                      Nonionizing= Damage of DNA

• Uses: Ionizing- not widespread routine

                Non-Ionizing- radation is not very penetrated

Canning:

• Mechanism of Action: many industries have standards for amount of thermophilic bateria allowed

•  Uses: If canned foods are exposed to high heat temps, the thermophilic bacteria that we commercially standardized for saftey can reappear causing food spoilage

Food Microbiology: Use of Microorganisms

Dairy Products:

1. Milk: Sterlile when in udder
   
   
2.  Cheese:
   - Seperates whey (liquid) from protein curd (casein)
   - Use S.lactis and S.cremoris to produce latic acid
   - Cheese classified according to hardness
   - Inoculated with additional microbes to produce various
     types if cheese

Food Microobiology: Use of Microorganisms

Dairy Products (Continued)

3) Butter: fat globules

- Leuconstoc sp.- produces diacetyls

- Requires: S. lactis & S.cremoris

4) Buttermilk- like butter, but use skim milk & microbe

5) Yogurt: low fat evaporated milk

- Lactobacillus & S. thermophilus

6) Kefir & Kumiss- Milk fermented with yeast

 Food Microbiology: Use of Mircroorganisms

Non- Dairy Products:

1. Bread: Made with yeast, CO2 makes bread rise
   
   
2. Sauerkraut, Pickles, Olives: made with Leuconstoc & Lactobacill.
   
   
3. Soy Sauce: made with Aspergillus oryzae

 Food Microobiology: Use of Microorganisms

Beverages

1.  Cider: apples contain sugars and yeast
   
   
2. Vinegar: -Acetobacter or Gluconobacter
   - Made from cide or wine
   - Converts ethanol to acetic acid
   
   
3. Alcoholic Beverages: -Beer=barley or other carbohydr. -Wine=grape -Sake=rice
   -Rum=sugar cane
   -Vodka=potatoes
   

Food Microobiology: Use of Microorganisms

Single Celled Protein: (SCP)

• Microbes are high in protein
  
  
• Supplement diet with microbes
  
  
• Used in: Animal foddes (animal food)
  
  
• Torula sp.(yeast) and certain bacteria used.

Industrial Microbiology-

Amino Acid Production:

1) Glutamic Acid:

- 600,000 tons/year

- Food condiment

- MSG~ food allergies

- Produced by~ Micrococcus and Corynebacterium glutamicum

2) Lysine:

- 70,000 tons/year

- 30% used for industrial purposes

 Industrial Microbiology-

Citric Acid Production:

• 300,000 tons/year

• Aspergillus niger converts: molasses to citric acid

• 70% used in the food industry; 30% used for industrial purposes

Industrial Microbiology-  

Enzymes:

1) Proteases: break down proteins

- Aspergillus sp. & Bacillus sp.

-Detergents, meat tenderizers, leather production, chill-proffing beer

2) Amylases: break down starches

- Aspergillus sp. & Bacillus sp.

 3) Lactase: break down lactose
     -Yeast

Industrial Microbiology-

 Antibiotic Prodution:

1) Fungal Sources:

- Penicillium & Cephalosporium

- Penicillin, cephalothins, and griseofluvin

 2) Bacterial Sources:

- Bacillus sp.- bacitracin & polymyxin

- Streptoyces sp.- streptomycin, tetracycline, amphotercin, chloramphenicol

Industrial Microbiology-

 Agricultural Uses:

1) Rhizobium: Nitrogen fixation

- Symbiotic realtion with~ legumes

- Mixed with peat moss to retain moisture and then seeded with legumes to ensure infection of the plant

 2) Bacillus thuringiensis (Bt)

- Microbe eats mosquito larvae

- Used in~ Municipal Control® programs & home gardeners

Alternative Energy Sources:

 1) Biomass: organic matter produced by living organisms including crops, waste, & trees

 2) Bioconversion: using microbes to convert biomass

3) Biofuels: ethanol from agricultural crops

Genetic Engineering:

1) Recombinant DNA- any artificial manipulation of genes within a species or between diff. species

2) Restriction Enzymes- enzymes that cut DNA into pieces that are easy to recombine in-vitro

3) Vector- plasmid or virus that inserts genes into a cell

4) Clone- genetically identical cells

Medical Therapy:

• Human insulin~ E.Coli carries human gene that makes this hormone
  
  
•  Human Growth Hormone (Somatostatin)
  
  
• Hep. B. Vaccine~ yeast carries VIRAL gene

Gene Theapy:

1. Replace: defective or mutated gene
   
   
2. Cystic Fibrosis: inhalation of a harmless cold virus that carries the healthy gene that the person lacks
   
   
3. Agammaglobulinemia: inability to produce Anti-Bodies
   
   
4. Addition of: genetically engineered virus to the bone marrow

 Genetic Engieering: Applications

Agricultural Uses:

• Bovine Growth Horomone (BGH)
  - E. Coli carries gene
  - Gene for pest resistance inserted into plants
  - Insertion of N-fixation genes into plants