Bacterial diseases are caused by harmful bacteria (pathogenic bacteria). The vast majority of bacteria do not cause disease, and many bacteria are actually helpful and even necessary for good health.
Bacterial diseases occur when pathogenic bacteria get into an area of the body that is normally sterile, such as the bladder, or when they crowd out the helpful bacteria in places such as the intestines, vagina or mouth. Less common, bacterial infections can occur when healthy bacteria multiply uncontrollably.
Various ways pathogenic bacteria can enter the body. Pathogenic bacteria can enter the body through a variety of means including:
Contamination of bites, cuts, rashes, abrasions and other breaks in the skin, gums and tissues
Eating contaminated food
Getting bitten by an infected insect
Having sexual contact with an infected person
Inhaling contaminated air-borne droplets into the nose and lungs
Kissing an infected person
Sharing needles for tattooing or drug use
Through the eyes, ears or urethra
Touching infected feces or body fluids, and not washing your hands before eating or touching your mouth, eyes or nose
Once bacteria enter the body, a healthy immune system will recognize the bacteria as foreign invaders and try to kill or stop the bacteria from reproducing. However, even in a healthy person, the body is not always able to stop the bacteria from multiplying and spreading. As the harmful bacteria reproduce, they can crowd out healthy bacteria and microorganisms and emit toxins that damage the cells of the body.
What are the risk factors for bacterial diseases? Bacterial diseases can occur in any age group or population, but a number of factors increase the risk of developing bacterial diseases. Not all people with risk factors will get bacterial diseases. Risk factors for bacterial diseases include:
Being an infant, child or older adult
Eating eggs or meats that are raw or undercooked
Eating expired foods, or eating leftovers that have been stored for more than two to three days
Having a genetic predisposition to bacterial infection