1. 18.6 Bacterial Diseases and Antibiotics KEY CONCEPT Understanding bacteria is necessary to prevent and treat disease.

2. 18.6 Bacterial Diseases and Antibiotics Some bacteria cause disease. Bacteria cause disease by invading tissues or making toxins. A toxin is a poison released by an organism.

3. 18.6 Bacterial Diseases and Antibiotics Normally harmless bacteria can become destructive. –may colonize new tissues

4. 18.6 Bacterial Diseases and Antibiotics –immune system may be lowered Normally harmless bacteria can become destructive.

5. 18.6 Bacterial Diseases and Antibiotics 1.Tuberculosis: bacteria multiply in the lungs, killing white blood cells and damaging lungs. Host coughs and spreads disease through the air. 2.Staph: Bacteria found on the skin, can be transferred on foods when handler does not wash before preparing food. More resistant strains evolving in hospitals 3.Botulism Clostridium infection in improperly canned foods. Release toxins that paralyze muscles. Used in Botox for wrinkles 4.Streptococci “Strep” strains can cause a flesh-eating infection. Enter the body through a scrape or cut. Strep throat is spread person-to-person

6. 18.6 Bacterial Diseases and Antibiotics Antibiotics are used to fight bacterial disease. Antibiotics may stop bacterial cell wall formation. Antibiotics do not work on viruses. Prevention is best method to fight bacterial disease. Do not touch you mucous membranes with dirty hands Stay away from sick people Stay rested and well-nourished

7. 18.6 Bacterial Diseases and Antibiotics Bacteria can evolve resistance to antibiotics. A bacterium carries genes for antibiotic resistance on a plasmid. A copy of the plasmid is transferred through conjugation. Resistance is quickly spread through many bacteria. Bacteria are gaining resistance to antibiotics. –Overuse: used as preventative in agriculture –Underuse: not completing entire course –Misuse: used to treat a viral infection Antibiotics must be used properly.