A bacterial infection is an infection caused by bacteria. Bacterial
infections can often be treated successfully with antibiotics.
An infection may begin as a bacterial infection. Or a bacterial
infection may follow a viral infection that does not get better. When a viral
infection doesn't get better for 10 days or more, or when a viral infection
starts to improve and then unexpectedly gets worse, a bacterial infection may
be more likely.
A bacterial infection usually affects a single area in the body,
such as the sinuses, lungs, ears, or urinary tract. Common bacterial infections
include sinusitis, pneumonia, strep throat, ear infections, and bladder
infections. If untreated, a bacterial infection can spread to the bloodstream. This condition is called bacteremia.