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Bacterial Infections
and
Importance of Bacteria
Bacterial Diseases
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Tuberculosis
Bubonic plague
Tetanus
Leprosy
Lyme disease
Bacterial meningitis
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E. coli
Typhoid fever
Rheumatic fever
Diphtheria
Scarlet fever
Cholera
MRSA
What is MRSA?
• MRSA = Methicillin-resistant Staphylococcus
aureus
• Commonly found on skin
• Resistant to antibiotics usually used for staph
infections…but usually treatable
• Can cause acne, boils, toxic shock syndrome,
bone infections, pneumonia
• Passed thru skin-to-skin contact or through
shared items/surfaces contacted
Ring-around-the-Rosies
• A song about the “Black Death”
• “Ring around the rosies” refers to the rosy
cheeks
• “Pocket full of Posies” refers to the people
carrying flowers in the pocket to cover up the
stench
• “Ashes, ashes we all fall down” refers to the
ashes from the dead and the # of dead
Why do we get sick from bacteria?
• Bacteria produce 2 kinds of toxins:
1. Endotoxin – found within the cell walls of
the bacteria
• All produce the same general symptoms:
fever, weakness, intestinal problems
• Can produce more serious problems with
circulatory system (ex. Typhoid fever,
Rheumatic fever)
2. Exotoxin – a waste product of the
bacteria’s function
• Are more deadly/potent
• Most can live without oxygen
(Ex.
Botulism)
• Botox uses a small amount of the
botulism toxin to temporarily paralyze
muscles
Examples of bacteria
Typhoid Fever
Botulism
Bacterial Cell Wall
• Made of combination of sugar and protein
• One way to classify bacteria is stain them by a
process called Gram staining:
– Gram-positive bacteria - bacteria stains purple
because the cell wall is mostly sugar (easier to kill)
– Gram-negative bacteria - bacteria stain pink
because the wall is mostly made of protein (harder
to kill)
Gram-positive vs. Gram-negative
p. 363
Controlling Bacteria
• Most bacteria are controlled by nature
(controlled by food or other resources)
• Dehydration – removing water
• Temperature control – making it too hot or
too cold to live
– Pasteurization: the process of heating food
(ex. Milk) to kill bacteria
– Refrigeration – slows down the
reproduction of bacteria
• Antibiotics: a substance produced by a
microorganism which can kill/inhibit the
growth of a different microorganism
– Penicillin works by interfering with the
ability to make the cell wall (dissolves the
sugar)
– Tetracyline interferes with protein synthesis
(broad spectrum antibiotic)
– Erythromycin interferes with protein
synthesis
Alexander Flemming
• English scientist who discovered penicillin (on
accident) in 1928
• Penicillin is a toxin (poison) produced by
penicillium fungus
• Was a major medical advance used in WWII
*Notice
the clear
ring
around
the disk
in the
middle…
no
bacteria!
Bacteria resistant to antibiotics
Gonorrhea
Syphilis
Economic Importance
• Nitrogen-fixation – bacteria that can change
nitrogen in the air to a usable compound for us
– Ex. crop rotation
• Recycle nutrients, decomposers
• Food
– Creates flavors/smells in cheese, yogurt,
vinegar
• In the medical field
– We use bacteria to “grow” vaccines
– Some bacteria kill other strains of bacteria
(ex. On skin…staphylococcus epidermis)
– Estimated that ½ of all disease is caused by
bacteria
• Produces jobs
• Produces $$ for prescription drug
companies
Question
• Based on the colors of
these bacteria, what
testing method was
used?
– Gram Staining
• Are they gram-positive
or gram-negative?
– Both…they’re gramvariable