Bacterial Colonization on Human Skin
Chapter One
PREAMBLE TO THE STUDY
Microorganisms of the normal flora may aid the host [By competing for micro-environment more effectively than such pathogens Salmonella Spp or by producing nutrients that the host can use. It may harm the host by causing dental caries, abscesses or other infectious diseases or it may exist as commercials by inhabiting the host for long periods without causing detectable harm or benefits. Even though most elements of the normal microbial flora inhabiting the human skin, nails, eyes, genitalia and gastrointestinal tract are harmless in healthy individuals, these organisms frequently cause disease in compromised hosts.
CHAPTER TWO
LITERATURE REVIEW
The body surface habour many microorganism which could be bacteria and fungi. Bacterial survival and the extent of colonization probably depend partly on the exposure of skin to a particular environment and partly on the innate and species of a specific bactericidal activity in the skin. Conversely, Streptococci viridans are not seen in large numbers on the skin or in the nose but dominate the oral flora. They synthesize and excrete vitamin in excess of their own needs which can be absorbed as nutrients by their host. It prevent colonization by pathogens by competing for attachment sites or for essential nutrients. This is though to be their most important effect which has been demonstrated in the oral cavity, the intestine and the skin. They may antagonize other bacteria through the production of substances which inhibit or kill non-indigenous species. The intestinal bacteria produce a variety of substance ranging from relatively nonspecific fatty acids and peroxides to highly specific bacteriocins which inhabit other bacteria. It stimulate the development of certain issues that is the caecum and certain lymphatic tissues in the gastrointestinal tract. It also stimulate the production of natural antibodies. Since the normal flora behave as antigens in an animal, they induce an immunological response in particular antibody-mediated immune response. Bacteria normal flora colonizes various parts of the body which include the following: oral cavity, skin, conjunctiva, teeth, nucous membranes, upper respiratory tract, nasal membrane, pharynx [throat], Gastroin testinal tract, Stomach, small intestine, colon, urinogenital tract and virginal.
Characteristics of few Bacterial Skin Flora
The common predominant bacteria floras are Staphylococcus epidermis corynebacteria, Streptococci and Lactobacilli.
Staphylococcus epidermis is a major inhabitat of the skin and in some areas it makes up more than 90% of the resident aerobic flora. The skin microbes can also be found in the most superficial layers of the epidermis and in the upper parts of the hair follicles. They also produce fatty acids that inhibit the growth of fungi especially the yeast on the skin.
Corynebacteria and certain related propionic acid bacteria are consistent skin flora. Some have been implicated as a course of acne. Conynebacterium diphtheriae, the agent of diphtheria was considered a member of the normal flora before the widespread use of the diphtheria toxoid which is used to immunize against the disease.
Staphylococcus are rarely seen on normal skin. They are occasionally found on the normal flora of the conjunctiva. The paucity of β-hemolytic streptococci on the skin is attributed at least in part to the presence of lipids on the skin Hemolytic streptococci exist primarily in the mouth from where they are they can also spread to the skin.
Lactobacilli. In the oral cavity probably contribute to acid formation that leads to dental caries. Lactobacillus acidophilus colonize the vaginal epithelium during child bearing years and establishes the low pH that inhibits the growth of pathogens. Lactobacilli are though to adhere to the gastrointestinal epithelium using polysaccharide capsule to attach to specific receptions on the epithelia cells. The major body part in which invasion of bacteria occurs mostly are on skin and gastrointestinal tract.
Gastrointestinal Tract
The stomach is a relatively hostile environment for bacteria. In the upper gastrointestinal tract of adult humans, the esophagus contains only the bacteria swallowed wit Sp Saliva and food. Because of the high acidity of the gastric juice, very few bacteria [mainly acid-tolerant lactobacilli] can be cultured from the normal stomach. Some Helicobacter Species can colonize the stomach and are associated with type β gastritis and peptic ulcers disease. Aspirates of duodenal or jejunal fluid contain approximately 103 organisms/ml in most individuals. Most of the bacteria cultured [Streptococci, Lactobacilli and Bacteroides] are thought to be transiat.
Although the normal flora can inhibit pathogens many of its membrane can produce disease in humans. Anaerobes in the intestinal tract are the primary agents of intra-abdominal abscesses and peritonitis. Bowel perforations produced by appendicitis, Cancer, infarction, surgery or gun shot wounds almost always seed the peritoneal cavity and adjacent organs with the normal flora. It can cause problems within the gastrointestinal human. Treatment with antibiotics may allow certain anaerobic specifics to become predominant and cause disease. For example, Clostridium difficile which can remain viable in a patient undergoing antimicrobial theory may produce Pseudomenbranous colitis other intestinal pathological conditions or surgery can cause bacteria over growth in the upper layer of intestine. Anaerobic bacteria can then deconjugate bile acids in this region and bind available Vitamin B12 so that the vitamin and facts are malabsorbed.
CHAPTER THREE
MATERIALS AND METHODS
MATERIALS USED
Petridish, Microscopic slide, autoclave, conical flask swab stick, wire loop, distilled water, aluminum foil, weighing balance, cotton wool, spirit lamp, test tube, glass spreader, needle and syringe, incubator.
STERILIZATION OF MATERIALS
All glass wares used were washed and rinsed properly with distilled water and dried. Glass wares were sterilized using hot air oven at 1800c for 30 minutes in order to kill the spores of any contaminants that might have sticked on to them.
The inoculating loop was sterilized with 95% ethanol and later flamed before and after used.
COLLECTION OF SAMPLES
The samples was collected from the human body by rubbing a moistened swab stick over the surfaces of some part of human’s body such as hand, toes, leg and neck.
2ml of sterile water was measured into test-tubes and the sample was placed inside the test-tubes for the sample to homogenize.
PREPARATION OF CULTURE MEDIA [NUTRIENT AGAR]
It was prepared according to the manufacturer direction 28g of Nutrient agar was weighed on a weighing balance and it was transferred into a clean sterile conical flask and 100mls of distilled water was added and shaked. It was then heated on hot plate to dissolved in order to give a clear solution the conical flask was cork with cotton wool and wrapped with aluminum foil and sterilized in an autoclave at 1210c for 15 minutes. The prepared medium was then allowed to cool and poured into a sterile petridish before solidifying.
CHAPTER FOUR
RESULTS AND DISCUSSION
A total of (3) bacteria were isolated and identified to be staphylococcus aureus, Klebsiella aurogene and Streptococcus pyogene (Table 4.1).
CHAPTER FIVE
CONCLUSION
Human skin microflora are important because it plays a strong role in regulating the feeding behaviour and the maintenance of good health. The presence of human skin microflora essential for immunity as these residence microbes defend their territory against disease causing microbes. In addition, skin microflora perform many important functions for us. It produce vitamins, help digesting of food and working as in an essential part of our immune system. Therefore care must be taken to maintain these body skin flora for the betterment of our body system and the control measure is very necessary for protection against the pathogenic and parasitic microflora.
RECOMMENDATION
Since all these organisms are responsible for one disease or the other on the skin. It should therefore recommend that proper hygiene must be monitored among the people in a community; there must be health education to the people in rural area to understand the risk of exposure to unhygienic environment. And a risk that may occur in washing skin repeatedly.
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