ORAL MICROBIAL
FLORA AND
MORPHOLOGY OF
BACTERIA
PRESENTED BY: ASHWINI AJAY
GUIDED BY: Dr. RAMESH
SYNOPSIS
Morphology of bacteria
difference between prokaryote and
eukaryote cell
size of bacteria
shape of bacteria
bacterial anatomy
growth , multiplication and bacterial growth curve
bacterial nutrition
Staining
Oral microbial flora
Normal microbial flora
normal microbial flora of the mouth
acquisition of normal flora of mouth
INTRODUCTION
Microorganism are
living structure of
microscopical size.
They are classified in
the group Protista
EUKARYOTIC CELL
ALGAE
FUNGUS
PROTOZOA
SLIME MOULD
PROKARYOTIC CELL
Streptococcus bacteria
E.Coli
SIZE OF BACTERIA
SHAPE OF THE
BACTERIA
BACTERIAL
ANATOMYCELL WALL
Cell wall is a tough and rigid structure,
surrounding the bacterium like the shell.
GRAM POSITVE GRAM NEGATIVE
It is 5- 10 nm thick elastic semi
permeable layer
Acts as an osmotic barrier
Site of numerous enzymes (
permease, oxidase, polymerase )
Acts as a semipermeable membrane
CYTOPLASMIC MEMBRANE
Bacterial nucleus has no nuclear
membrane
some bacteria may possess
extranuclear material in the
cytoplasm consisting of DNA named
plasmids and episomes
NUCLEUS
Viscid layer that surrounds the bacteria
as the outermost layer.
When it diffuse into the surrounding
medium it remains as a loose
undemarcated secretion is known as
slime layer.
When this secretion is orginized it is
called capsule.
BACTERIAL CAPSULE AND SLIME LAYER
They are cytoplasmic appendages
protruding the cell wall.
they are composed of protein called
flagellin , it is 5-20um in length &
0.01-0.02 in diameter.
FLAGELLA
Filament
Hook
Basal Body
PARTS OF FLAGELLA
ARRANGEMENT OF FLAGELLA
•Amphitrichous - single flagellum at both ends
• Monotrichous - single polar flagellum
• Lophotrichous - Tufts at one or both ends
• Peritrichous - Arranged all round the cell
GROWTH OF BACTERIA
BACTERIAL GROWTH CURVE
BACTERIAL NUTRITION
STAINING
DIFF
STAIN
NEGATIVE STAINSIMPLE STAIN IMPREG STAIN
GRAM STAIN ACID FAST STAIN
GRAM STAINING
process of gram staining
RESULT
ACID FAST STAIN
RESULT
MICROBIOLOGY OF
OROFACIAL REGION
One of the most varied and
numerous floras in the human body.
More than 500 bacterial taxa are
found in the oral cavity out of which
22 predominant ones.
ACQUISITION AND
VARIATION
At birth oral cavity is sterile
Becomes colonised by the environment
in particular mothers milk
98 % Sterptococcus salivarius
Eruption of teeth
Colonization by S.mutans and S.
sanguinis
Requires non- epithelial surface to
colonize
Colonize as long as the teeth is in the oral
cavity
REGULATING FACTORS
MICROORGANISIMS
Aerobic Anaerobic
-ve rods+ve rods-ve cocci+ve cocci +ve cocci -ve cocci +ve rods -ve rods
GRAM POSITIVE COCCI AND BACILLI
GRAM POSITIVE COCCI
GRAM POSITIVE BACILLI
GRAM NEGATIVE COCCI
GRAM NEGATIVE BACILLI
THANK YOU

ORAL MICROBIAL FLORA