How the Body Works : How Bacteria Cause Disease

How the Body Works How Bacteria Cause Disease Bacteria usually gain entrance to the body either by inhalation, by ingestion, or through a break in the skin. Once they have entered a tissue, the bacteria may produce a substance known as the spreading factor. The spreading factor digests connective tissue barriers in the tissues, thus allowing further spread of the bacteria or their toxins. Failure to overcome these invasive agents can lead to severe tissue damage. Large numbers of bacteria may compete with the healthy cells for nutrients and oxygen. Toxins, on the other hand, disrupt normal cell metabolism by interfering with chemical reactions. When a tissue becomes infected by bacteria, white blood cells migrate to the site of infection and begin to ingest the bacteria. The bacteria, however, may survive and multiply within the white cells, which then burst, releasing the bacteria into the tissue once again, causing severe inflammation. More white cells then enter the area to try to combat the infection. White blood cells are attracted to an infected site where bacteria are multiplying and causing inflammation. Some bacteria have thick capsules around them which prevents them from being engulfed, consequently, the bacteria increase. The body then manufactures antibodies which attach themselves to the bacteria, making them vulnerable to ingestion by the white cells. In this illustration the infected site is supplied with white blood cells. The bacteria have gained entry ...