Bacteria are among the oldest living organisms. Bacteria can be found everywhere. Some bacteria are inoxious; but others can invade humans’ bodies and harm them. Antibodies protect people against infections. Antibiotics destroy most bacteria; and the immune system is able to handle the surviving bacteria. Some antibiotics work to interfere with the metabolism of bacteria, slowing them down and making them easier to deal with. Other antibiotics attack bacterial DNA; making the genome unable to replicate so the bacteria can’t reproduce and ultimately die. Other antibiotics destroy the cellular membrane, causing the cell cytosol to go into the environment, causing the bacteria to die.
Some mutant bacteria may be able to alter the antibiotics or pump the antibiotics out, thus preserving the life of the bacteria. Bacteria can spread by transduction (when plasmids as well as immunity spread to new cells) or transformation (where bacteria pick up DNA from lysed bacteria). A lot of immune bacteria exist in hospitals since patients may spread their nosocomial infections. Very strong antibiotics are used to battle these bacteria. Additionally, in the mass growing of livestock for animals living in close quarters, where bacteria may be spread, the animals must be fed antibiotics in their feed to kill the harmful bacteria that they might develop.