Identification of normal bacteriological flora of skin,


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It was my project presentation in M.Sc. final year. Special thanks for Fareeha Shamim who made it for our group.

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Identification of normal bacteriological flora of skin,

  1. 1. Bacteriological Analysisof Normal Flora of Skin,Nasal and Ear Specimens Sonia Akhtar, Xia Mujahid, Sobia Ishaque and Fareeha 26 April, 2012
  2. 2. Introduction: The human microbiome (or human microbiota) is the aggregate of microorganisms that reside on the surface and in deep layers of skin, ear, in the saliva and oral mucosa, in the conjunctiva, and in the gastrointestinal tracts. They include bacteria, fungi, and protozoa. Some of these organisms perform tasks that are useful for the human host. Those that are expected to be present, and that under normal circumstances do not cause disease, but instead participate in maintaining health, are soul members of the normal flora.
  3. 3.  It is estimated that 500 to 1000 species of bacteria live in the human gut and a roughly similar number on the skin.Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 1014 versus 1013).Though members of the flora are found on all surfaces exposed to the environment (on the skin and eyes, in the mouth, nose).
  4. 4.  Different harmless microorganisms establish as commensals or mutualistic with the host. Normal flora can be divided into two groups, residential flora and temporary flora. The normal flora as well as host immune status both do not allow to infect the host. The environmental conditions like pH, temperature, availability of oxygen, presence of moisture etc also influence their presence.
  5. 5. Aim: The basic aim of this studywas to analyze the normal flora of Skin, Nose and Ear
  6. 6. Materials and Methods: Samples of nose , ear & skin were collected by the normal healthy individuals by the help of swabs in aseptic conditions. Media: which were used are nutrient agar, sheep blood agar, MacConkey agar, Manitol salt agar, Muller Hinton Agar and Salt Indol Motility agar.
  7. 7. Table 1. Colonial morphology, microscopicexamination and hemolysis SPECIMEN BLOOD AGAR MACCONKEY AGAR NUTRIENT AGAR GRAM REACTION MOTILITY EAR 1 γ hemolysis Colorless colonies Small, rounded, opaque colonies Gram positive Non-motile cocci EAR 2 β hemolysis Colorless colonies Small, rounded, golden yellow Gram positive Non-motile colonies cocci NASAL 1 β hemolysis Colorless colonies Small, rounded, opaque colonies Gram Negative Non-motile diplococci NASAL 2 β hemolysis Large, shiny, mucoid , pink Large, opaque colonies Gram Negative Non-motile colonies bacilli SKIN 1 β hemolysis Colorless colonies Small, rounded, opaque colonies Gram positive Non-motile cocci SKIN 2 γ hemolysis Colorless colonies Small, rounded, opaque colonies Gram positive Non-motile cocci
  8. 8. Table 2. Biochemical tests for Gram negativeisolates UREA LACTOSE ORGANISMSPECIMEN TSI IMViC Butt Slant H2S Gas I MR VP C NASAL 2 +ve +ve Klebsiella Acid Acid +ve -ve -ve +ve +ve +ve pneumoniae Gram negative isolated colonies TSI and Citrate results of Gram showing lactose fermentation and negative bacilli isolated from nasal mucoid growth on Macconkey agar specimen no.2 plate
  9. 9. Table 3. Biochemical tests SUGARS OrganismSPECIMEN GRAM UREA CAT. OXI. COAGULASE lac suc mal men identified REACTION Gram positive + - + - + + + - Streptococcus viridans EAR 1 cocci Gram positive EAR 2 cocci - + - + + + - Staphylococcus aureus Gram NegativeNASAL 1 diplococci - + + - + + + - Niesseria spp. Gram NegativeNASAL 2 bacilli + - + - + + + - Klebsiella pneumoniae Gram positive - - + - + + + - Streptococcus epidermidis SKIN 1 cocci Gram positive - - + - + + + - Streptococcus epidermidis SKIN 2 cocci
  10. 10. Table 4. aaantibiotic succeptibility Antibiotics Culture codes P Cl S Amp Be EAR 1 - - - - - EAR 2 3mm 6mm 9mm 1mm 2mm NASAL 1 - - - - 2mm NASAL 2 - - 2mm - - SKIN 1 12mm 10mm 6mm 6mm 2mm SKIN 2 11mm 10mm 5mm 6mm 3mm Antibiotic susceptibility Isolated pure cultures from specimens
  11. 11. RESULTS: The Ear specimens 1 and 2 were identified as Streptococcus viridans and Staphylococcus aureus Nasal specimens 1 and 2 were identified as Niesseria spp.and Klebsiella pneumoniae Nasal specimens 1 and 2 were identified as Niesseria sp Non of the isolated organisms showed sensitivity against antibiotics
  12. 12. DISCUSSION: The varied environment of the skin results in locally dense or sparse populations, with Gram-positive organisms (e.g., staphylococci, micrococci, diphtheroids) usually predominating. S. epidermidis is a major inhabitant of the skin, and in some areas it makes up more than 90 percent of the resident aerobic flora.
  13. 13.  Streptococci, especially β-hemolytic streptococci, are rarely seen on normal skin. The paucity of β- hemolytic streptococci on the skin is attributed at least in part to the presence of lipids on the skin, as these lipids are lethal to streptococci. Gram-negative bacteria make up a small proportion of the skin flora.Gram-negative bacteria, is more common in the moist intertriginous areas.
  14. 14. • The nose and perineum are the most common sites for S. aureus colonization, which is present in 10 percent to more than 40 percent of normal adults. S. aureus is prevalent (67 percent) on vulvar skin. Its occurrence in the nasal passages varies with age, being greater in the newborn, less in adults. S. aureus is extremely common (80 to 100 percent) on the skin of patients with certain dermatologic diseases such as atopic dermatitis, but the reason for this finding is unclear.
  15. 15. THANKYOU