How does the misuse of antibiotics cause resistance?

Question

I was just reading an article on wikipedia about antibiotic resistance and it said that "The widespread use and misuse of antibiotics has resulted in increased microbial resistance to antibiotics in clinical use". Can anyone explain to me how antibiotics have been misused and why it has caused bacteria to become resistant?

Answer 1

the bacteria develop an immunity to the antibiotics.

Answer 2

bacteria evolves, only the strongest survive, the resistant one survive and so they reproduce the likes of them all resistant

Answer 3

As bacteria replicate their DNA in preparation for cell division, small, infrequent errors creep into the replicated DNA.  Every now and then the mutation gives rise to increased resistance to a drug, antimicrobial or other environmental stress.  These are the most likely to survive in the presence of that stress.  Bacteria divide frequently and don't check their DNA for errors as carefully as we do, so mutations arise in relatively high numbers (compared to, say, mammals).

Taking an antibiotic as prescribed usually kills the entire population of bacteria, resistant ones and all, or at least enough of them that your immune system can "mop up" the rest.

If you take an antibiotic, but not in a sufficiently high dose or for a sufficient period of time, you may kill *most* of the bacteria, but the few survivors are more likely to harbor mutations that give them a survival advantage against the drug.  

These "more resistant" bacteria will go on to divide and accumulate more mutations, some of which will make them even more resistant than they already are.  Thus improper antibiotic use can lead to the development of drug-resistant strains.

This is the essence of evolution - survival of the fittest - when a species is challenged by a new stress.  Bacteria just do it on a remarkably faster time-scale than we do.

Answer 4

If you overuse antibiotic, you develop immunity/tolerance to them.