How do you get/what are bacterial infections?

Bacteria are single-celled microorganisms. Bacteria are able to survive in many types of environments in and on the human body. Most bacteria cause no harm to people. For infecting organisms to survive, they must leave an existing reservoir — either within the current host or in another host — and cause infection in another place.

Bacterial infections may be marked by localized redness, inflammation, pain or swelling.

Bacterial infections may be transmitted through direct or indirect contact with a reservoir of infectious bacteria.

Direct contact occurs when an individual comes into contact with the reservoir via touching infected bodily fluid; sharing beverages containing infectious bacteria; being bitten by an insect or other animal that is carrying the bacteria; or inhaling bacterial particles, often emitted by sneezing or coughing. Sexual contact is a common mode of direct transmission of bacterial infections.

Certain bacteria are able to survive outside of a host and remain infective for extended periods of time. Indirect infection occurs when an individual comes in contact with such an organism. These organisms may be found anywhere, but when they exist on toys, furniture, door knobs or other personal care products used by people, transmission is more likely to occur. Consumption of contaminated food is another common mode of indirect transmission of bacterial infections.

Transmission may occur through fecal-oral contact, which occurs when sewage water is consumed or used to wash food. Such transmission often occurs in developing countries with poor sewage or drainage systems.

The above modes of infection are examples of horizontal transmission, which is when organisms are transmitted from person to person in the same generation or from living person to living person. Vertical transmission occurs when the infection is passed from mother to child during childbirth or fetal development.

Examples of other common bacterial infections include chlamydia, ear infections, Helicobacter pylori, Lyme disease, methicillin-resistant staphylococcus aureus and osteomyelitis.

Additional information about bacterial infections may be found at these websites:

http://www.who.int/vaccine_research/diseases/soa_bacterial/en/index2.html

http://www.mayoclinic.com/health/infectious-disease/AN00652

http://www.niaid.nih.gov/topics/bacterialinfections/pages/default.aspx

http://www.nlm.nih.gov/medlineplus/bacterialinfections.html