Microbiology
Micro-organisms exist everywhere - in the air that we breathe, in the soil, in non-processed foods, in dust and in all decomposing matter. Man and animals have micro-organisms living both on and in their bodies. Many micro-organisms are harmless under ordinary conditions, and some are actually useful.. Most plants and animals could not exist without the beneficial assistance of micro-organisms in removing various waste products.
Micro-organisms play an important role in the natural decay process.. They break down leaves and wood, animal carcasses, etc. City life depends on bacteria for sewage treatment. Micro-organisms are used to ferment alcoholic beverages, to make organic acids and to make foods such as yogurt, bread and cheese. Some micro-organisms are used to produce antibiotics.
Some micro-organisms are harmful and are responsible for illness and disease. micro-organisms can also damage commercial products such as plastics and adhesives. In the automotive arena, the micro-organisms that we are most concerned with are bacteria and fungi.
Bacteria
Bacteria are one-celled micro-organisms. Four hundred million (400,000,000) of these cells are about the same size a s a single grain of granulated sugar. Bacteria reproduce by dividing in half (fission) to produce two identical cells. Under ideal conditions, bacteria can reproduce every 15-30 minutes. One bacterium could become 70 billion bacteria in only 12 hours.
Bacteria are divided into two major groups. GRAM POSITIVE and GRAM NEGATIVE. Examples of Gram Positive bacteria are (Staphylococcus aureus) which causes acne, and (clostridium tetani) which causes tetanus. Examples of Gram Negative bacteria are (Pseudomonas aeruginosa) which breaks down and contaminates both living and on-living matter and (Salmonella typhosa) which causes typhus.
Some bacteria produce poisonous substance (toxins) that can cause disease such as lockjaw or food poisoning in man. Other bacteria produce enzymes that can dissolve or destroy living cells or commercial goods, foul surfaces that we contact daily, and contaminate equipment and foodstuffs. You would typically find these kinds of bacteria in substances such as spilled mil, spoiled food, blood, etc.
Fungi
Fungi are a large group on non-green plants that live by feeding on either living or dead organisms. Fungi cannot make their own food because they lack the green plant pigment chlorophyll. some fungi, such as a mushroom, are large. Over 100,000 species of fungi have been identified. Fungi and bacteria often co-habitate in nature.
Many fungi are useful. They are necessary in the making of bread, wine, cheese and beer. Mushrooms are used as a food source. Other fungi are troublesome, causing decay and mildew. Fungi will grow on a wide variety of both natural and synthetic surfaces.
Fungi can cause disease in humans. Coccidiosis and histoplasmosis are fungal diseases caused by inhaled spores which infect the lungs and other internal organs. Athletes foot and ringworm are infections of the skin and nails caused by fungi. In a vehicle you would find fungi usually in the air conditioning system, probably because of leaks.