3.32 understand that resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections being difficult to control

Bacteria experience mutations (the reproduce very frequently so it is not rare.) These mutations can mean that they are no longer affected by a certain antibiotic, this makes it easier for them to survive. If bacteria evolve to be resistant to drugs we are treating them with then they are difficult to control; sometimes they can be stopped using a different antibiotic, but some are becoming resistant to all the drugs that we know of...