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
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.