Ch. 19 – Importance of Bacteria!

Used in food – yogurt, cheese, sauerkraut Used in food – yogurt, cheese, sauerkraut Decompose dead things Decompose dead things E-coli in your stomach E-coli in your stomach Sewage treatment Sewage treatment Nitrogen fixation – convert nitrogen from air to a form that plants can use. Nitrogen fixation – convert nitrogen from air to a form that plants can use.

Bacteria & Disease: Examples of disease caused by bacteria: Examples of disease caused by bacteria:  Bubonic Plague – carried by fleas on rats.  “Ring around the Rosie Pocket full of posies Ashes, Ashes We all fall down”

Escherichia coli (E-coli) A whole family of bacteria, not all of which are harmful. A whole family of bacteria, not all of which are harmful. Good - Depend on E. coli in our intestines for Vitamin K and BGood - Depend on E. coli in our intestines for Vitamin K and B Bad - E-coli (0157:H7): symptoms: Bleeding, loss of water, kidney failureBad - E-coli (0157:H7): symptoms: Bleeding, loss of water, kidney failure

Pathogens – viruses and bacteria that are disease producing agents Pathogens – viruses and bacteria that are disease producing agents Virulence – the ability to cause disease Virulence – the ability to cause disease Some Terms to know:

3 Steps to Disease 1. Contamination: pathogens are present… a.Through air, food or water b. Direct contact (touch, body fluids, etc.) c. Contact with a carrier of a pathogen (tetanus [lockjaw] comes from bacteria found on soil particles)

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

3 steps continued… 2. Infection – pathogens multiply in body 3. Disease – disturbance in the healthy body, so it can no longer carry out its normal functions.

Bacteria cause disease in one of these 2 ways: 1. Break down cells to use as a food source. (Mycobacterium tuberculosis) 2. Release Toxins (E. coli) M. tuberculosis - destroys lung tissue; can enter blood stream & destroy other tissue.

Coping with Disease: Immunity – resistance to a pathogen that is acquired or inherited. Immunity – resistance to a pathogen that is acquired or inherited. Antibodies – proteins that the body makes to destroy pathogens. Antibodies – proteins that the body makes to destroy pathogens. Antibiotics – drugs that attack and destroy bacteria. (before these, people died of things like strep throat!) Antibiotics – drugs that attack and destroy bacteria. (before these, people died of things like strep throat!)

Major Antibiotic: Penicillin Penicillin Alexander Fleming 1928 discovered by accident in labAlexander Fleming 1928 discovered by accident in lab A type of moldA type of mold Different types (amoxicillin, etc. come from different forms of the Penicillin fungi – mold)Different types (amoxicillin, etc. come from different forms of the Penicillin fungi – mold)

Controlling Bacteria: 1. Sterilization – heat of chemicals to kill bacteria Bacteria cannot survive high temperatures for very long Bacteria cannot survive high temperatures for very long Examples: Autoclave at the vet, dentist, doctors office, etc. Examples: Autoclave at the vet, dentist, doctors office, etc.

2. Disinfectants – chemical solutions to reduce the number of bacteria Examples: Antiseptics, Antibacterial products (soaps, cleansers, kitchen utensils) Examples: Antiseptics, Antibacterial products (soaps, cleansers, kitchen utensils)

3. Soap – wash bacteria away; may be good enough 4. Food preservation – salt, vinegar, sugar, heat, low temperatures (refrigeration – doesn’t kill just slows growth!) Controlling bacteria continued…