Normal Flora

Question 1

Which of the sites that harbor a known normal biota?

Answer 1

• Skin and its adjacent mucous membranes
• respiratory tract and lungs
• G.I. tract
• outer opening of the urethra
• external genitalia
• Vagina
• external ear canal
• external eye (lids, conjunctiva)

Question 2

Which are the anatomical sites and fluids thought to be sterile

Answer 2

• Heart and circulatory system
• liver
• kidneys and bladder
• brain and spinal cord
• muscles
• bones
• ovaries and testes
• glands ( pancreas, salivary, thyroid )
• sinuses
• middle and inner ear
• blood
• urine
• cerebral spinal fluid
• saliva prior to entering the oral cavity
• semen prior to entering the urethra
• amniotic fluid surrounding the embryo and fetus

Question 3

Which are the factors that the normal flora is dependent on?

Answer 3

• Age
• sex
• stress
• nutrition and diet
• hygiene

Question 4

How does the flora maintain health?

Answer 4

• it occupies binding sites so that pathogens can’t become established
• produce bacterial toxins that kill other bacteria
• secrete vitamins B and K

Question 5

What are conditions that can increase the risk for disease by normal flora acting as opportunistic pathogens?

Answer 5

• Age
• overall health: infection, cancer, diabetes, malnutrition
• immunosuppressive therapy: chemotherapy, radiation therapy
• stress
• hygiene

Question 6

Name two diseases of the normal flora

Answer 6

• Bacterial vaginosis

- pseudo-membranous colitis ( seen in people with long-term antibiotic therapy )