Bacteria can develop mutations that provide them with resistance to antibiotic medications. Why would giving multiple antibiotics at once be less likely to create a population of resistant bacteria?
Bacteria would be able to survive the destruction of several genes at the same time.
Most bacteria would not develop all the mutations needed to resist multiple antibiotics given at the same time.
Giving one antibiotic at a time would allow the bacteria enough time to mutate.
Bacteria would need a base pair substitution to survive several antibiotics at a time.