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.