Microbiology of normal Flora of human body

Microbiology of normal Flora of human body

1. NORMAL FLORA

2. •Normal flora means the various bacteria and
fungi that are permanent residents of certain
body sites.
•The viruses and parasites are usually not
considered members of the normal flora,

3. Medically Important Members of the Normal Flora.
Location Important Organisms
Skin Staphylococcus epidermidis, Propionibacterium acnes, Staphylococcus
aureus, Pseudomonas aeruginosa, Candida.
Nose Staphylococcus aureus Staphylococcus epidermidis
Mouth Viridans streptococci, Candida albicans
Dental plaque Streptococcus mutans
Gingival crevicesVarious anaerobes, e.g., Bacteroides, Fusobacterium, streptococci,
Actinomyces
Throat Viridans streptococci, Bacteroides species, Neisseria, S.epidermidis
Colon Bacteroides fragilis, Escherichia coli, Candida albicans, Clostridium
species, Enterococcus faecalis, Lactobacillus species, Pseudomonas
aeruginosa,Bifidobacterium.
Vagina Lactobacillus, E. coli, group B streptococci,Bacteroides species, Candida
albicans, Corynebacterium, Gardnerella vaginalis, Staphylococcus
epidermidis
Urethra S. epidermidis, Corynebacterium (diphtheroids), various gram-negative
rods, e.g., E. coli.

4. •The members of the normal flora play their
role in three significant ways:
1.They can cause disease, especially in
immunocompromised and weak individuals.
These organisms are non pathogens in their
usual anatomic location, they can be
pathogens in other parts of the body.
2.They form a host defense mechanism. These
bacteria occupy attachment sites on the skin
and mucosa and interfere with colonization by
pathogenic bacteria.

5. 3. They have a nutritional function. The intestinal
bacteria produce several B vitamins and
vitamin K.
•Carrier state:
•The term "carrier" means that an individual
carries a potential pathogen and therefore can
be a source of infection for others.
•Colonization:
•It means acquisition of a new organism. After
the new organism colonizes it may cause an
infectious disease or it may be eliminated by
our host defenses.