2007-05-12 15:31:38 · 9 answers · asked by miss 1 in Science & Mathematics ➔ Medicine
Bacterias develop resistance through natural selection. When a drug is first used, there will already be some bacterias that are more resistant to the drug than others. Most of the bacterias that do not have the resistance will die. The remaining surviving bacterias will be mostly resistance. Bacterias have a high reproduction rate which allows it to speed up the adaptation process. Because only the bacterias that are resistant will be alive to reproduce, this creates more bacteries that have a higher chance of also being resistant. The process continues over several cycles until bacteria basically develops 'immunity.'
2007-05-12 15:57:24 · answer #1 · answered by hi O__o 3 · 1⤊ 0⤋
The individual bacteria do not change, but some bacteria are just lucky enough to not be killed by the drugs. Those bacteria that can stand the drug are the ones that survive and reproduce. So the next generation of bacteria has more of the kind that can resist the drug. Over time the resistance becomes common in the population.
2007-05-12 15:36:15 · answer #2 · answered by ecolink 7 · 1⤊ 0⤋
If you mean why does bacteria develop drug resistence, there are a few reasons. Most common reason: People dont finish all their antibiotics, which kill most of the bacteria, but not all. The ones not killed are weakened, but when the antibiotic is gone, they grow back stronger, and since they have been exposed to the drug, they develop a mutation to resist the drug.
2007-05-12 15:35:27 · answer #3 · answered by Angie 3 · 2⤊ 1⤋
In addition to the other good answers given here, once one resistant species of bacteria evolve, viruses may carry genes between different species. That amplifies the problem: e.g. bacteria that live in the gut of chickens fed antibiotics in food, and which have evolved resistance to the antibiotic, might be harmless to people. Viruses might then carry the "resistance" genetic information to a human pathogen. This is bad news.
2007-05-12 17:36:31 · answer #4 · answered by Anonymous · 1⤊ 0⤋
All cells have mutations in their DNA when they reproduce.
There are millions of bacteria in your body, on your skin, in your mouth, nose and in your intestines.
They divide every few hours and when they divide they make copies of their DNA.
Occasionally they make a mistake when copying their DNA.
Most of these mistakes are harmful to the bacteria, but occasionaly one of this mistakes or mutaitons helps the bacteria.
For example a mutation might allow the bacteria to produce an enzyme that breaks down pennicilan.
So the antibiotic will kill 99.999% of the bacteria but the resistant ones survive and get spread to another person.
The same thing happened when DDT was used to spray for mosquitos
Maybe the
2007-05-12 15:54:01 · answer #5 · answered by michael971 7 · 1⤊ 0⤋
Because a few are more immune to the drug than others, and when the rest are killed, these few reproduce and form a new resistant strain.
2007-05-12 15:35:56 · answer #6 · answered by Eric 4 · 1⤊ 0⤋
they might bypass antimicrobial resistance by way of plasmid transference (a fashion of shifting genetic textile between micro organism) additionally with certainly one of those dissimilar quantities and their speedy multiplication the genetic version in a inhabitants , organic determination can happen. non resistant ones die off and resistant ones multiply. this technique basically happens whilst uncovered to the antibiotic.
2016-10-04 23:51:21 · answer #7 · answered by ? 4 · 0⤊ 0⤋
it's the law of nature. when a species is threatened to extinction by an outside source, it'll evolve future generations to be resistant, even immune.
2007-05-12 15:35:00 · answer #8 · answered by jqdsilva 3 · 2⤊ 1⤋
Like all living organisms, survivors get acquired immunity from a certain disease, or drugs.
2007-05-13 06:48:08 · answer #9 · answered by WC 7 · 0⤊ 0⤋