Lecture notes Medical Microbiology

Microbial Flora Of Human
Body -
Internal


The tract tract have direct contact with the outside of the
•

digestive ,
respiratory tract and
urogenital body.




•
They also have their own microbial
community .




Oral cavity
•
The oral cavity provides an excellent environment for microbial

growth :




-
Constant temperature
-


Moist environment

Ready supply of nutrients
-




Range of surfaces for attachment
-

.




Due to food and drink that the microbes
•
being ingested ,
there is a risk will be washed
away .




•
Therefore microbes attach to surfaces and also form biofilms .




•
There are a number of different attachment sites available :


-



Tongue
-


Epithelial cells
-
Teeth etc .




Dental microbes

•
Plaque is an example of a biofilm found on the teeth .




•
Plays a role in both tooth
decay and halitosis .




• Microbes attach but can be shed to some extent ( coughing / talking) .




• There are numerous microbes in the mouth -

some permanent resident .




•
Examples of bacteria found here include :




Porphyromonas SPP
Streptococcus mutans
Fuso bacterium Streptococcus
-




sobrinus
.




spp
-
-
-
.




Nasal cavity / Respiratory Tract

•
The nasal cavity also provides favourable conditions for microbial growth .




•
Moist conditions , relatively constant temperature nutritional ,
sources from secretions .




Microbes enter the nasal
•
cavity during inhalation .




also be true but the mouth provides
• In more distal areas of the
respiratory tract this can a
point of
contact via
pharynx .




• Examples of bacteria found here include :




Staphylococcus aureus Streptococcus pyogenes Neisseria meningitidis Corynebacterium diphtheria