Ch. 19 – Importance of Ch. 19 – Importance of Bacteria!Bacteria!

Used in food – Used in food – yogurt, cheese, yogurt, cheese, sauerkrautsauerkraut

Decompose dead Decompose dead thingsthings

E-coli in your E-coli in your stomachstomach

Sewage treatmentSewage treatment Nitrogen fixation – Nitrogen fixation –

convert nitrogen convert nitrogen from air to a form from air to a form that plants can use.that plants can use.

Bacteria & Disease:Bacteria & Disease: Examples of disease caused by bacteria:Examples of disease caused by bacteria:

Bubonic PlagueBubonic Plague – – carried by fleas on rats. carried by fleas on rats. ““Ring around the RosieRing around the Rosie

Pocket full of posiesPocket full of posiesAshes, AshesAshes, AshesWe all fall down”We all fall down”

Escherichia coli (E-coli)Escherichia coli (E-coli) A whole family of bacteria, not all of A whole family of bacteria, not all of

which are harmful.which are harmful.• GoodGood - Depend on E. coli in our - Depend on E. coli in our

intestines for Vitamin K and Bintestines for Vitamin K and B

• BadBad - E-coli - E-coli (0157:H7)(0157:H7): symptoms: : symptoms: Bleeding, loss of water, kidney failureBleeding, loss of water, kidney failure

PathogensPathogens – viruses and bacteria – viruses and bacteria that are disease producing agentsthat are disease producing agents

VirulenceVirulence – the ability to cause – the ability to cause diseasedisease

Some Terms to know:Some Terms to know:

3 Steps to Disease3 Steps to Disease1.1. Contamination:Contamination: pathogens are pathogens are

present…present…

a.a. Through air, food or waterThrough air, food or water

b. Direct contact (touch, body fluids, b. Direct contact (touch, body fluids, etc.)etc.)

c. Contact with a carrier of a c. Contact with a carrier of a pathogen pathogen (tetanus [lockjaw] (tetanus [lockjaw] comes from bacteria found on soil comes from bacteria found on soil particles)particles)

Tetanus - medical condition characterized by a prolonged contraction of skeletal muscle fibers

3 steps continued…3 steps continued…

2.2. Infection – pathogens multiply in Infection – pathogens multiply in bodybody

3.3. Disease – disturbance in the healthy Disease – disturbance in the healthy body, so it can no longer carry out body, so it can no longer carry out its normal functions.its normal functions.

Bacteria cause disease in one of these 2 Bacteria cause disease in one of these 2 ways:ways:

1.1. Break down cells Break down cells to use as a food to use as a food source. source. ((Mycobacterium Mycobacterium tuberculosistuberculosis))

2.2. Release Toxins Release Toxins ((E. coliE. coli))

M. tuberculosis - destroys M. tuberculosis - destroys lung tissue; can enter lung tissue; can enter blood stream & destroy blood stream & destroy other tissue.other tissue.

Coping with Disease:Coping with Disease:

Immunity – resistance to a pathogen Immunity – resistance to a pathogen that is acquired or inherited.that is acquired or inherited.

Antibodies – proteins that the body Antibodies – proteins that the body makes to destroy pathogens.makes to destroy pathogens.

Antibiotics – drugs that attack and Antibiotics – drugs that attack and destroy bacteria. destroy bacteria. (before these, (before these, people died of things like strep people died of things like strep throat!)throat!)

Major Antibiotic:Major Antibiotic:

PenicillinPenicillin• Alexander Fleming Alexander Fleming

1928 discovered by 1928 discovered by accident in labaccident in lab

• A type of moldA type of mold• Different types Different types

(amoxicillin, etc. (amoxicillin, etc. come from different come from different forms of the forms of the Penicillin fungi – Penicillin fungi – mold)mold)

Controlling Bacteria:Controlling Bacteria:

1.1. Sterilization – heat of chemicals to kill Sterilization – heat of chemicals to kill bacteriabacteria

Bacteria cannot survive high temperatures Bacteria cannot survive high temperatures for very longfor very long

Examples: Autoclave at the vet, dentist, Examples: Autoclave at the vet, dentist, doctors office, etc.doctors office, etc.

2.2. Disinfectants – chemical solutions to Disinfectants – chemical solutions to reduce the number of bacteriareduce the number of bacteria

Examples: Antiseptics, Antibacterial Examples: Antiseptics, Antibacterial products (soaps, cleansers, kitchen products (soaps, cleansers, kitchen utensils)utensils)

3.3. Soap – wash bacteria away; Soap – wash bacteria away; may be good enoughmay be good enough

4.4. Food preservation – salt, Food preservation – salt, vinegar, sugar, heat, low vinegar, sugar, heat, low temperatures (refrigeration – temperatures (refrigeration – doesn’t kill just slows growth!)doesn’t kill just slows growth!)

Controlling bacteria continued…