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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
Mode of Transmission
Botulism
Clostridium botulinum Nerves
Improperly preserved
foods
Cholera
Vibrio cholerae
Intestine
Contaminated water
Dental caries (tooth
decay)
Streptocooccus
mutans and salivarius
Teeth
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
• 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