How can infections become so resistant to antibiotics?

I recently found out that the bladder infection I had that rose up into my kidneys was resistant to more than 8 types of antibiotics, hence the kidneys getting affected when penicillin was doing nothing for my bladder. I am now have IV treatment on an antibiotic they hope will rid it after 2 weeks of pain. How can... show more I recently found out that the bladder infection I had that rose up into my kidneys was resistant to more than 8 types of antibiotics, hence the kidneys getting affected when penicillin was doing nothing for my bladder. I am now have IV treatment on an antibiotic they hope will rid it after 2 weeks of pain. How can infections become so resistant that they avoid 8 types of Antibiotic?
5 answers 5