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How bacteria resist antibiotics
Genetic exchanges that confer antimicrobial resistance
FDA video: antimicrobial resistance
RESISTANCE IS CONFERRED
DO ANTIBIOTICS KILL BACTERIA?
Antibiotics work in many ways. Several ways in Which antibiotics kill
bacteria are listed below and shown in Figure
with bacterial cell wall synthesis
bacterial protein synthesis at the ribosome
3. Inhibit function of enzymes involved in DNA synthesis by masquerading
as a natural component of the synthetic machinery
OF RESISTANCE DEVELOPMENT
Bacteria can develop resistance through genetic mutation (“resistance
genes”). These mutations enable the bacteria to alter the way it
interacts with the antibiotic agent, rendering the antibiotic harmless.
Such mutations cause the following to happen (Figure
(of the antibiotic)—bacteria develop methods to throw
antibiotics out of the cell (efflux) or decrease their uptake (influx).
plug formation—a protein is produced to block the uptake
of drug into the cell.
blockade—the bacteria produces a protein that blocks
the ability of the antibiotic to bind to ribosomes.
destruction—the bacteria produces an enzyme that destroys
the antibiotic before it can produce its effect.
of the drug—the antibiotic itself is altered by bacterial
enzymes, making it ineffective.
BACTERIA TRANSFER RESISTANT GENES TO ONE ANOTHER
Bacteria can share the DNA that makes them resistant to
antibiotics with other bacteria in their environment. Bacteria share DNA
with other bacteria through these mechanisms (see Figure
uptake of free DNA in the environment. The free DNA usually comes from
the breakdown of dead bacteria nearby.
transfer of plasmids, or small circular pieces of bacterial DNA, containing
resistance genes, from one bacteria to another.
transfer of bacterial DNA via viruses, or bacteriophages, to other closely-related
bacteria. Bacteriophages are viruses that infect only bacteria.
SHORT VIDEO ON ANTIMICROBIAL RESISTANCE
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