1. Define normal microbial flora of the human body.
ANS: The different types of bacteria and fungi that are found at certain sites of our body, which includes the skin and mucous membranes of oral cavity, vagina, upper respiratory tract, lining of gastrointestinal tract, intestines; residing permanently are described as normal microbial flora.
2. Describe the role of normal microbial flora.
ANS: The normal flora plays an important role in causation of disease and in maintaining health of an individual.
• They show a property called colonization resistance, where they serve as a limit for the growth of other pathogens in body.
• They play a nutritional role, since the intestinal flora synthesize essential nutrients that include vitamin B and vitamin K.
• By fighting against the foreign pathogen, it maintains our innate immunity.
• Aids in the absorption and digestion of nutrients.
• In neonates, it is the normal flora that provide immunity to the body.
• In people with impaired immune system, they can be responsible for causing disease.
• If displaced from their usual location, they can act as pathogens, resulting in disease.

3. Enumerate the types of flora in various body sites.
ANS:
NOSE:
• Staphylococcus aureus
• Staphylococcus epidermidis
• Corynebacterium species
MOUTH:
• Streptococcus species
• Fusobacterium species
• Actinomyces species
• Leptotrichia species
• Veillonella species.
THROAT:
• Streptococcus species
• Corynebacterium species
• Branhamella catarrhalis
• Haemophilus species
• Neisseria species.
• Mycoplasma species.
SKIN:
• Staphylococcus epidermidis
• Propionibacterium acnes
• Pityrosporum ovale
LARGE INTESTINE:
• Escherichia coli
• Bacteroides fragilis
• Proteus mirabilis
• Streptococcus species
• Enterococcus species
• Klebsiella species
• Pseudomonas species
• Candida albicans
• Clostridium species
VAGINA:
• Lactobacillus species.
• Candida albicans
• Gardnerella vaginalis
• Streptococcus species.
URETHRA:
• Streptococcus species
• Mycobacterium species
• Escherichia coli
• Bacteroides species