Microbiology: Normal Flora

Front 1

What is normal flora?

Back 1

Commensal microorganisms that normally live on the human body

Front 2

Normal flora and skin

Back 2

Skin is generally dry and slightly acidic with a high concentration of NaCl that causes a hyperosmotic environment; resident flora live in multiple layers and are generally harmless; S. epidermis, Propionibacterium acnes (deep, anaerobic)

Front 3

Normal flora and the eye

Back 3

Conjunctiva of the eye is colonized by S. epidermis, S. aureus, and S. Pneumoniae; Tears contain lysozome

Front 4

Normal flora and the nose and mouth

Back 4

Aerobic and anaerobic bacteria; Corynebacterium, S. aureus, S. epidermis, S. mutans (teeth and gingiva, S. pneumoniae

Front 5

Normal flora and the intestinal tract

Back 5

Low pH in the stomach leads to low concentration of microorganisms, which increases along the alimentary tract

Front 6

Normal flora and the urogenital tract

Back 6

Low pH in the vagina from Lactobacillus; prevents growth of other pathogens such as yeast (Candida albicans); urine and bladder are sterile, but can be contaminated by flora of the skin

Front 7

Beneficial functions of normal flora: competition

Back 7

Normal flora occupy receptor sites and use up nutrients to make it more difficult for pathogens to establish themselves

Front 8

Beneficial functions of normal flora: production of antimicrobial substances

Back 8

Normal flora produce acid (Lactobacillus) and other animicrobial substances

Front 9

Beneficial functions of normal flora: development

Back 9

Colonization of a newborn stimulates the development of the immune system

Front 10

Beneficial functions of normal flora: metabolism

Back 10

Normal flora in the gut provide nutrients such as vitamin K and aid in digestion and absorption of nutrients

Front 11

Harmful effects of normal flora

Back 11

Changes in conditions can lead to potential pathogenesis (environment, immunoscompromise, carcinogenic derivatives)