Slides in this set
Antibiotic Resistance & MRSA
1. Recall how mutations can lead to
antibiotic resistance (LAST LESSON).
2. Describe how resistance can be passed
on through both vertical and horizontal
3. Describe how antibiotic resistance has
made it difficult to treat diseases such as
Tuberculosis and MRSA.…read more
1. Antibiotics are chemicals that either kill or inhibit the growth
of bacteria / fungi.
2. Antibiotics interfere with essential processes in bacterial
cells e.g. cell wall formation, DNA replication etc.
3. Mutations change the base sequence of DNA, this may alter
the structure of the protein targeted by the antibiotic,
preventing it from working.
4. Resistance is clearly an example of natural selection
because a useful characteristic (resistance) is selected for,
becoming more frequent in a population.
· Variation some bacteria have alleles for resistance some don't.
· Selective pressure the antibiotic kills any without resistance alleles.
· Inheritance resistant bacteria survive and reproduce.
· Time after time, most bacteria in the population will carry the
resistance allele.…read more
Why has antibiotic resistance become
an increasing problem?
· Increasing use of antibiotics;
· Increased exposure of bacteria to antibiotics;
· Patients frequently fail to complete their course
· Any bacteria with mutations that confer
resistance survive; those without resistance do
· Removal of competitors allows rapid increase in
number of resistant bacteria;
· Antibiotics ineffective against resistant strains…read more