Transcript 18.6 Bacterial Diseases and Antibiotics

18.6 Bacterial Diseases and Antibiotics
KEY CONCEPT
Understanding bacteria is necessary to prevent
and treat disease.
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.
18.6 Bacterial Diseases and Antibiotics
Antibiotics are used to fight bacterial disease.
• Antibiotic: Chemicals that kill or slow the growth of
bacteria.
– Work by breaking down the cell wall of bacteria.
18.6 Bacterial Diseases and Antibiotics
• Normally harmless bacteria can become destructive.
– immune system may be lowered
18.6 Bacterial Diseases and Antibiotics
Bacteria can evolve resistance to bacteria
Creates selective pressure that favors
the bacteria they intended to destroy.
Failure to take entire course of
antibiotics - doesn’t destroy them all.
Antibiotics fed to livestock
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.