skin microflora / normal flora of skin

Download Skin microflora / Normal Flora of Skin

Post on 15-Dec-2014




1 download

Embed Size (px)


This slide gives an idea of the innumerable microorganisms present on the skin, and how they have positive and negative effect on the human body.



2. Skin Skin is the organ of the human body that protects from the pathogens from the environment and retards the loss of excessive water. Its other functions are insulation, temperature regulation, sensation and synthesis of vitamin D. The skin is composed of the epidermis , dermis and fat cells. 3. This layer consist of dead cells( without nucleus) and constantly in contact with microorganism from the environment. Impermeable to microorganism; however cuts, abrasion and wounds can allow the organisms to penetrate. Consist of connective tissues and cushions the body from heat and strain. Has sebaceous gland, sweat gland, hair follicles and nerve endings. 4. It attaches the dermis layer to the underlying bones and provides with blood. It functions as padding and insulation. 5. NORMAL SKIN MICROBIOTA The skin is hostile to the survival and growth of microorganisms. Skin flora can be comensalistic, mutalistic or pathogenic. The flora depends on the area, the clothing, occupation and environment. e.g. Pathogen Streptococcus pyogenes does not survive for more than a few hours when applied to the skin whereas it may survive in room air for weeks. 6. Some of the common flora on skin are: Bacteria: Staphylococcus aureus folliculitis, boils, etc. Staphylococcus epidermis - Impetigo, Abscess Staphylococcus warneri - Endocarditis, UTI Propionibacterium acnes Acne vulgaris Pseudomonas aeroginosa - Folliculitus 7. Folliculitis Impetigo 8. S. epidermis S. aureus 9. Propioniobacterium acnes 10. Fungal colonies: Candida albicans - Candidiasis Trichosporon cutaneum White piedra Microsporum gypseum Dermatophytosis 11. There are some microbes present on skin which actually increase the immunity to fight pathogenic organisms e.g. P. Acnes inhibits the growth of many pathogenic microrganisms but under some conditions the organism can even cause infection( i.e. acne vulgaris) 12. FACTORS RESPONSIBLE FOR DISCOURAGING MICROBIAL COLONIZATION ON SKIN 1. DRYNESS: Dry surface is inhibitory to microbial growth. Some regions of the skin are moist than others, e.g. The axillary region, toe webs and the perineum( skin at the lower end of the trunk between the thighs.) These regions has higher number of normal flora organisms than the drier area of skin. 13. 2. Low Ph: Skin has a normal pH between 3 and 5 and it is higher in moist regions. This low pH is due to the lactic acid or other organic acids produced by normal skin microorganisms such as staphylococci. This factor discourages the growth of other organisms. 14. 3. Inhibitory Substances: Sweat glands secrete lyzozyme that destroys bacterial cell walls. Sebaceous glands secrete complex lipids which may be partially degraded by Propionibacterium acnes, that results in long chained unsaturated fatty acids e.g. Oleic acid. This fatty acids are highly toxic to other bacteria. 15. BENEFIT OF SKIN FLORA The benefits bacteria can offer include preventing transient pathogenic organisms from colonizing the skin surface, either by competing for nutrients, secreting chemicals against them, or stimulating the skin's immune system. 16. DISADVANTAGE OF SKIN FLORA Even resident microbes can cause skin diseases and enter the blood system creating life-threatening diseases particularly in immuno suppressed people. 17. THANK YOU!


View more >