Because people (including doctors) keep using antibiotics for inappropriate purposes, including treatment of the common cold, which is a virus. Viruses are not affected by antibiotics.
Constant exposure to antibiotics in the environment has resulted in mutations of bacteria so that they are antibiotic resistant. Thus, it is necessary to continue to develop new antibiotics to deal with these new super-bacteria.
It should be said that the drug companies themselves are largely responsible for this, as they constantly lobby to allow antibiotics to be used unnecessarily, such as in treatment of poultry and other animals that are to be slaughtered for meat. This saves money, but it also releases huge amounts of drugs into the environment. (See above for results) The pharmaceutical giants thus get richer in two ways: selling the old drugs and developing and marketing new ones.
Certain types of antibiotics will kill certain types of bacteria.
The types of drugs that can kill bacteria are called 'antibiotics'.
bad ones
There are several types of antibiotics that all act in different ways. Could you be more specific?
A stem cell can develop into other types of cells.
Certain types of antibiotics will kill certain types of bacteria.
Antibiotics are usually given to someone who is sick with an infection. There are many types of antibiotics.
different antibiotics are used for fighting different types of bacteria.
Antibiotics can cure all types of bacterial infections.
Antibiotics only cure bacterial infections. Antibiotics will not cure a viral infection.
There are no antibiotics for the bird flu. Influenza (all types) is caused by a virus, and hence can't be treated with antibiotics (antibiotics only work with bacteria).
Viruses are not killed by antibiotics; there are also other types of sickness, such as cancer, which cannot be killed by antibiotics. Antibiotics are only useful for treating bacterial infections.
In each of the three types, researchers found different but measurable impairments on objective testing of neurological function.
Antibiotics.
coca cola and mirinda.
Some antibiotics, such as penicillin, affect only certain types of bacteria but not other types.
The types of drugs that can kill bacteria are called 'antibiotics'.