This article from the WHO states:
If you stop treatment early, there is a risk the antibiotics won’t have killed all the bacteria that made you sick and that it will mutate and become resistant. This will not happen to everyone – the problem is that we don’t know who can safely stop treatment early.
By taking the full course prescribed by your doctor, even if you start to feel better earlier, you increase the chances of killing all of the bacteria and reduce the risk of resistance.
- A clarification: When the WHO says “[bacteria] will mutate and become resistant,” they are implying that using antibiotics will create a selective pressure for bacteria with antibiotic resistance, arising most likely through mutations, correct? Bacteria don’t mutate into antibiotic resistant strains in direct response to a drug; rather, antibiotic resistance is a phenomenon of natural selection. I’ve seen so many articles about antibiotic resistance worded this way and I feel it’s simply wrong.
- Presuming I am correct about my first point, here’s my true question: Say you’re prescribed a course of antibiotics. It kills the bacteria that are not resistant to the drug and leaves those that have developed resistance behind. What does it matter if you finish the whole course? Taking more of the drug is not going to affect the resistant strain. The only rationale I can think of is that it would kill off any residual non-resistant bacteria and prevent them from gaining resistance (via conjugation) from the resistant kind. However, is this the only mechanism whereby completing the course prevents the rise of antibiotic resistance? How effective is this at all at preventing the rise of antibiotic resistance in the bacterial population in general (i.e. beyond the host)?