Pathogenic Bacteria

Pathogenic bacteria (bacteria capable of causing disease) because they release chemicals called toxins. Toxins are classified as either endotoxins or exotoxins.

Endotoxins produce toxic substances which are stored in their cell walls and released when the bacterial cells are lysed (broken open). Endotoxins produce localized effects, are less toxic than exotoxins and are not destroyed by heat.

Exotoxins excrete toxic proteins which are usually the result of bacterial metabolism. Exotoxins produce systemic, potent effects and are usually heat-sensitive.

Antibiotics, typically found in molds, can kill bacteria. But in an infection, there may be a small fraction of bacteria with DNA codes that make them resistant to the antibiotic. If such bacteria are not killed by the antibiotic and the natural immune mechanisms, they may come to take over the infection and make the patient untreatable. Taking antibiotics for less than the prescribed number of doses is dangerous because there is a good chance that only antibiotic-resistant bacteria will remain alive.  Without having to compete with non-pathogenic bacteria and non-resistant bacteria, antibiotic-resistant bacteria will then become very difficult to eliminate.

Not all bacteria cause disease. Many bacteria help prevent disease by competing with pathogenic bacteria.