Eli5 why not finishing a full course of antibiotics causes resistant strains of bacteria

1.12K views

My understanding is that the antibiotics won’t kill the random mutant bacteria anyway, so doesn’t killing off all the susceptible ones just allow for more room for the mutants?

Does it have to do with more base bacteria getting the chance to mutate? A specific resistance has to be pretty rare right? Or will you have multiples of the same mutation in a “colony”?

In: Biology

6 Answers

Anonymous 0 Comments

There exists resistance in the group. Antibiotic kills the bugs without resistance, leaves behind bugs that can survive the antibiotic. Leaves more resources for those bugs that then multiply. The few resistant bugs become the majority.

Edit: I think I misunderstood. So you aren’t normally aiming for killing all the bugs, but enough that your immune system can do the job. So if you take an appropriate course of antibiotics, there are low enough quantities for your immune system to handle. If you take less, you may have killed some of the susceptible bugs, but not enough. So then you have a mix of resistant and susceptible bugs that survived that can overwhelm your immune system. For certain types of resistance, the factors that lead to it can be traded among the colony. Now you have overwhelming infection with large quantities of resistant organisms

You are viewing 1 out of 6 answers, click here to view all answers.