How frequent can you use antibiotics?

How soon can you use the same antibiotic regimen?

• The first thing we need to avoid is antibiotic resistance.
• The next thing is the adverse effect of antibiotic course, i.e. deprivation of good bacteria
• The natural microbial flora should also be reconsidered. 

After a first course of antibiotics for 7-10 days, almost all of the susceptible organisms have been dead but a few strain, resistant strains, will still remain.
We need to wait for the period of re-colonization wherein, the resistant strain and susceptible strain in the body have again equal number of population. This is done to avoid a population of microbes that are all resistant.

So the right question is:
How long will it take for a certain species of good bacteria to recolonize our body? 

• It usually takes more than 6 months to have complete recolonization of all the good bacteria (Gut bacteria), depending on the antibiotic course.

Other key notes: 

• Clinically, it is recommended to avoid the same class of antibiotics for 3 months.
• Abrupt use of the same antibiotic regimen after a week will have no more effect since majority of the microbial population are the resistant strains. 
• Thus, it is wise to use the same antibiotic regimen 6 months apart, allowing recolonization and prevention of resistance at the same time. 

This question is in lieu of certain medical conditions that often predisposes a patient to frequent infections. I.E., Chronic sinusitis

Antibiotic Therapy General Principle
Gut bacteria Recovery