Before the large-scale medical use of antibiotics, the drug resistance effect was almost meaningless to bacteria, and the harmful effect of mutation itself was more important. Normal use of antibiotics can kill almost all target bacteria, and individual fish that miss the net are usually eliminated by the human immune system. Although some of these bacterial individuals already have drug-resistant buds, these buds are not enough to withstand normal doses of antibiotics and will disappear when the individual dies. It can be inferred from this:. ['Gene mutation is the root cause of the spread of drug-resistant bacteria.', 'Bacteria use genetic mutations to weaken the effects of antibiotics.', 'Antibiotics will not be able to attack the germs after they become resistant.', 'Drug resistance will not spread quickly without antibiotic abuse.']