Fungi are eucaryotic organisms existing as single cells (yeasts) and as multicelled filaments (molds and mushrooms). Even though fungi are plantlike in their structure, they cannot perform photsynthesis and must depend on organic matter for their nourishment. The life forms of fungi are slightly more advanced than bacteria, but not as high as plants. Fungi secrete digestive enzymes, and then absorb the product breakdown, as in the decaying process of dead plants and animals. There are approximately 250,000 species that are very important in the decomposition of organic matter, but only about 200 species are associated with diseases. Most fungal diseases in humans are caused by only ten or fifteen different species, but these few can be deadly if they invade a person with a compromised or weakened immune system. Life-threatening fungal pathogens include Histoplasma capsulatum and Coccidiordes immitis.
Opportunistic fungal infections most often strike individuals who are immunocompromised. A variety of agents are responsible for these secondary diseases. Fungal opportunistic pathogens are frequently of the genera Candida and Aspergillus, and no group of organisms is more opportunistic than fungi. Patients of bone marrow transplants are uniquely susceptible to Fusarium infections; children on long-term steroid therapy are prone to infections caused by Rhodotorula; patients with tumors of the blood are susceptible to the Trichsporon species; and leukemia patients are frequently victims of Mucor or Rhizopus. However, the most frequent cause of infections regardless of the type of immune system compromise is Candida.
Fungi are parasitic plants that can grow in between body cells, playing havoc with the immune system. Normally, such annoying diseases as athlete’s foot, yeast infections, ringworm, thrush, and certain lung diseases can be deadly to those with a compromised immune system. Various bacteria found naturally on the skin also help to ward off most fungal cells. With an increased presence of yeast, Staphylococcus bacteria grows at a rate 500% faster than if yeast were not present. With the increased use of bacterial soaps, the risk for fungal infections increases.
Iron plays an essential role in carrying oxygen throughout the body, but it also is required by bacteria, fungi, protozoa, and tumor cells for their growth. Therefore, taking in more iron than the body requires only encourages the growth of pathogens.