Bacteria and Humans Describe the ways that bacteria
Bacteria and Humans
• Describe the ways that bacteria can cause disease in humans • Specify how antibiotic resistance has come about, and describe ways that bacteria resist antibiotics • List three ways that bacteria are helpful to humans
• Bacteria cause disease • Bacteria benefit us in food preparation and in environmental, chemical, and mining process
Bacteria and Disease • Pathology: study of disease • Pathogens: bacteria that cause disease • Toxins (From Greek for poison used in arrows): Poison made from living cells – Hemotoxins: destroy RBCs, Pit Viper Venom – Necrotoxins: destroy all tissue types, Brown Recluse, and Necrotizing Fasciitis – Neurotoxins: nerve cells, black widow, scorpions, box jelly fish
• Exotoxins: toxins made of protein • Botulinum from Clostridium botulinum. – One of most poisonous substances – The most poisonous protein – Used in small doses to treat muscle spasms, and as botox – Poor canning
• Clostridium perfringens • In every bit of dirt you can find • Can cause gangrene & food poisoning
• Clostridium tetani – Causes tetanus – Uncontrolled muscle spasms • In the jaw = lockjaw •
Disease Pathogen Area Affected Botulism Clostridium botulinum Nerves Improperly preserved foods Cholera Vibrio cholerae Contaminated water Dental caries (tooth decay) Streptocooccus mutans Teeth and salivarius Environment Gonorrhea Neisseria gonorrhoeae Urehtra, fallopian tubes, epididymis Sexual contact Lyme disease Borrelia burgdorferi Skin, joints, heart Tick bite Rocky mountain spotted fever Rickettsia ricketsii Blood, skin Tick bite Salmonella food poisoning Salmonella Intestine Contaminated water and food Strep throat Streptococcus pyogenes Upper respiratory tract, blood, skin Airborne Tetanus Clostridium tetani Nerves at synapses wounds Tuberculosis Mycobacterium Lung, bones, other coughs Intestine Mode of Transmission
• Endotoxins: toxins made of lipids and carbohydrates – Inside bacteria – Hurt us when they die
Antibiotics • Drugs that interfere with cellular functions • Penicillin: can’t make cell walls – Some are allergic • Tetracycline: bacteria can’t make proteins • Sulfadrugs: made in labs • Broad-spectrum drugs: affect a variety of organisms
Antibiotic Resistance • When a few mutant bacteria survive antibiotics a resistant population will grow as their descendents. • Antibiotics puts selective pressure for resistant bacteria to succeed. • Overuse of antibiotics is making generations of resistant bacteria difficult to treat
Useful bacteria • Bacteria break down waste in treatment facilities • Bacteria ferment lactose to make products such as buttermilk, sour cream, and yogurt. • Bacteria digest protein in milk to make cheese – Digest carbs in cabbage to make sauerkraut
Useful bacteria • Produce chemicals and fuels • Clean up environmental disasters
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