1. Ramesh kumar 1

2. Normal Flora Definition Normal flora is the mixtureof microorganisms (bacteria and fungi) that are regularly found at any anatomical site of human body. 2

3. 3

4. Symbiotic relationship MutualisticCommunalisticOpportunistic 4

5. Symbiotic Relationship 1. Mutualistic Both organisms benefit – “mutually beneficial” 2. Commensalistic One organism benefits, the other is neither helped nor harmed 3. Opportunistic Under normal conditions, microbe does not cause disease, but if conditions become conducive, it can cause disease 5

6. Mutualistic Escherichia coli Synthesizes Vitamin K & B complex Vitamins In return, we provide a warm, moist nutrient rich environment for E. coli 6

7. Commensalistic We have no Commensalistic relationships with Bacteria If Bacteria are in or on our body, they are either helping us (Microbial Antagonism) or harming us. 7

8. Opportunistic Escherichia coli - normally in our digestive tract where it causes no problems, but if it gets into the urinary tract it can become pathogenic. Staphylococcus aureus – commonly found in the upper respiratory tract, but if it gets into a wound or a burn it can become pathogenic 8

9. The Three Types of Symbiotic Relationships Table 14.1 9

10. Types of normal flora Resident Flora Transient Flora 10

11. Normal Microbial Flora 1. Resident Flora Microbes that are always present 2. Transient Flora Microbes that live in or on your body for a period of time (hours, days, weeks, months) then move on or die off 11

12. 12

13. Transient Microbiota Remain in the body for only hours to months before disappearing Found in the same regions as resident microbiota Cannot persist in the body…because… Competition from other microorganisms Elimination by the body’s defenses cells Chemical or physical changes in the body 13

14. Sterile tissues In a healthy human, the internal tissues such as: blood brain muscle cerbrospinal fluid (csf.) are normally free of microorganisms. Normal Flora 14

15. Normal Flora Skin Eyes (i.e.Cunjunctiva) Nose (i.e. Respiratory tract) Mouth (i.e Human Oral Cavity) Ears Urogenetal tract Elementry tract 15

16. Normal Flora Resident flora Acquired rapidly during & after birth 16

17. Normal Flora Resident flora Reflects age of person 17

18. . Normal Flora Resident flora Changes continuously through out life 18

19. Normal Flora Resident flora Reflects nutrition of person 19

20. Normal Flora Resident flora Reflects genetics of person 20

21. Normal Flora Resident flora Reflects environment of person 21

22. Resident flora Reflects sex of person Normal Flora 22

23. 1.They constitute a protective host defense mechanism by occupying ecological niches. Importance of The Normal Flora (Advantages) 23

24. Importance of The Normal Flora (Advantages) 2.They produce vitamin B and vitamin K in intestine. 24

25. Importance of The Normal Flora (Advantages) 3.The oral flora contribute to immunity by inducing low levels of circulating and secretory antibodies that may cross react with pathogens. 25

26. Importance of The Normal Flora (Advantages) 4.The oral bacteria flora exert microbial antagonism against nonindigenous species by production of inhibitory fatty acids, peroxides, bacteriocins, etc. 26

27. Importance of The Normal Flora (Advantages) 5.The normal flora may antagonize other bacteria through the production of substances which inhibit or kill nonindigenous species. 27

28. Importance of The Normal Flora (Disadvantages) 1.They can cause disease in the following: a) When individuals become immunocompromised. b) When they change their usual anatomic location. 28

29. Thanks your 29