How are antibiotic-resistant forms of bacteria formed?

It's evolution at work.





Like humans and all other life forms, bacteria have a lot of diversity in their structures and chemistries. When treated with antibiotics, 99% of those bacteria will be susceptible to it, and will thus be destroyed, but a rare few will survive because of unusual features encoded in their DNA. Over time, they become more prevalent in the bacterial cultures.





Then, bacteria have a means for passing on segments of DNA that code for features necessary for survival, which they can then send to other bacteria. These segments are called plasmids, and the cells can excrete them, to be ingested by other bacteria. When cultures are repeatedly exposed to environmental pressures, such as antibiotics, these antibiotic resistant strains that survive pass on plasmids to the non-antibiotic resistant strains, thus making all of them antibiotic resistant.





Over time, this will occur with any bacteria species.

How are antibiotic-resistant forms of bacteria formed?
They are formed because people do NOT know how to finish the entire antibiotic they are given. Therfore the bacteria are not fully killed, the sickness comes back, and now a stronger antibiotic is needed to treat the same illness. So remember: finish your whole antibiotic even though you may be feeling better!
Reply:Natural selection. Bacteria reproduce very quickly, with many generations in very short periods of time. When a person starts an antibiotic regimen, but doesn't complete it, bacteria have the opportunity to randomly mutate a resistance to a given antibiotic before the entire population is killed.. They probably won't, but they can. if they do, we have a new, antibiotic-resistant strain.
Reply:it,s a known fact that given wrong meds for certain systoms will not destroy the infection.in other words,the right form of meds has to match/meet the criteria of which it can help etc. anti-bios basically attack certain bacteria,inclu your own good/friendly immune sys bacteria.if it,s a viral or fungal infection/origin then the virus/fungas will only mutate to a diff form to protect itself,thus a mutated form,that only will get stronger again if attack by another wrong med,so on and so on =mutation.bacteria being the simplest then virus and fungals at the top of the food chain of things that want us as their host,our living body to survive in,until they become stronger and we eventually do not.
Reply:When the doctor prescribes antibiotics for 5 days, some patients stops the medicine after 2 or 3 days due to side effects of the medicine or due to the fact that the symptoms of the disease have been vanished. Thus by partial administration of the medicines, the bacteria gets resistance over the antibiotics. Staphylococcus aureus, Neisseria gonorrhoeae, tubercle bacillus are becoming more and more resistant to drugs.


Another aspect in the resurgence of the disease(TB) is the development of drug resistant strains which now affect up to 50 million people. These strains can be created by bad medical practice such as over-prescribing antibiotics or patients not taking the drugs long enough to get rid of the disease. Instead this encourages the bacteria to become tougher.


Treating patients with drug resistant TB is beyond the pocket of many developing countries. The cost of treatment can rise from $2000 per patient with non-resistant TB to $250,000 for multi-drug resistant TB.


The multi drug resistant strains are often fatal and have mortality rates that are comparable with those which existed before the development of antibiotics.


Please see the web pages for more details on MRSA and Tuberculosis.