Introduction:
Microorganisms
are very tiny one-celled organisms, viruses, fungi, and bacteria, and are found
everywhere in the world. They are found in all living things, plants and
animal. There are more microorganisms on and inside your body than there are
cells that make up your entire body. Microorganisms can live in the air, on
land, and in fresh or salt water environments. Some of them, pathogens, can be
harmful and causes diseases, but there are some microorganisms that are needed
for living things to survive.
Airborne
microbes cause a lot of illnesses and diseases in humans. Microorganisms can
enter the air when a human or animal sneezes, or by the wind picking up the
light particles and blowing them where humans are. When a human sneezes
microorganisms leave the lungs at around 200 miles per hour. Some of the
microorganisms that are growing in the mucus in the respiratory tract enter the
air with the moisture particles that are sneezed out of the lungs. These
microorganisms can be breathed into the lungs of another person and that person
could get sick.
Many normal
flora provide direct benefits, such as making vitamins or aiding
digestion. Even if normal flora microbes merely take up space and resources,
they help prevent pathogens (disease causing microbes) from easily invading the
body and causing illness. Although there are many different species of normal
flora, these bacteria, fungi and protozoans typically fall into one of two
categories:
(a)
Resident microbiota
(b)
Transient microbiota
Resident Microbiota
The
body’s resident microbiota are just that — residents. These species are
life-long members of the body's normal microbial community, but are not found
everywhere. There are many areas of the human body that remain axenic, and, in
the absence of disease, are never colonized by normal flora. Axenic areas
include the body cavity, lungs, central nervous system, circulatory system and
upper urogenital regions.
Resident
microbiota typically colonize the surface of the skin, mucous membranes,
digestive tract, upper respiratory system and distal portion of the urogenital
system. These microbes have a commensal relationship with their host, meaning that
they do not cause harm while they benefit from feeding on the cellular waste
and dead cells of the host's body.
Transient Microbiota
Transient
microbes are just passing through. Although they may attempt to colonize the
same areas of the body as do resident microbiota, transients are unable to
remain in the body for extended periods of time due to:
- competition from resident microbes
- elimination by the body’s immune system
- physical or chemical changes within the body that discourage the growth of transient microbes
Objective:
To determine the microorganism in the air and from
healthy humans.
Material and reagents:
Molten
nutrient agar(commercial and own prepared), sterile water, sterile petri
dishes, sterile clinical swab, pipette and tips.
Procedure:
Air:
- The molten agar is poured into sterile petri dish and it is cooled.
- The lid is removed from the plate and it is left resting on the side of the plate, facing down. (The lid of the petri dish is never inverted.) The plates are left exposed for about 5 minutes.
- The lids are replaced and incubated at 37°C for 48 hours.
Hands:
- The hand is washed using sterile water. We did not use soap.
- An automatic pipette is used to transfer 1ml of wash water to the petri dish.
- The molten nutrient agar is added to the petri dish.
- The lids of the petri dish are replaced and are gently rotated the dish until the wash water is thoroughly mixed with the molten agar. The agar is not allowed to contact the lid of the dish.
- After the agar has set, the dish is inverted and incubated at 37°C for 48 hours.
Ear:
- The molten agar is poured into sterile petri dish and it is cooled.
- Using extreme care, a sterile swab moistened is rubbed with sterile isotonic solution into the ear of the subject.
- The swab is used to inoculate the labeled plate. The inoculum is distributed as in the streak method.
- The dish is inverted and incubated at 37°C for 48 hours.
Normal breathing:
- The molten agar is poured into sterile petri dish and it is cooled.
- The lid is removed and the plate is held about 15cm from your mouth. We have breathed normally but directly onto the plate for one minute. The lid is replaced.
- The dish is inverted and incubated at 37°C for 48 hours.
Violent coughing:
- The molten agar is poured into sterile petri dish and it is cooled.
- The lid is removed and the plate is held about 15cm from your mouth. We have coughed violently onto the agar. The lid is replaced.
- The dish is inverted and incubated at 37°C for 48 hours.
Results:
Air ( commercial )
Air ( own prepared )
Hand ( commercial )
Hand
( own prepared )
Ear
( commercial )
Ear ( own prepared )
Normal breathing ( commercial )
Normal breathing ( own prepared )
Violent coughing ( commercial )
Violent
coughing ( own prepared )
Discussion:
This pile of cells originates from one cell and is called a bacterial colony. Each species of bacteria produces a colony that
looks different than the colonies produced by other species of bacteria.
Examination of the form and structure of bacterial colonies is termed colony morphology and is one of the first steps in
characterizing and identifying a bacterial culture.
These are the characteristics used to accurately
and consistently describe the morphology of a bacterial colony:
- Size
The size of the
colony can be described in two ways. The more accurate technique would be to
measure the diameter of the colony with a ruler and report the size in
millimeters. The second technique would simply be to describe the colonies as punctiform (tiny
pinpoints), small, medium, or large.
- Shape
Shape refers to
the overall appearance of the colonies. The descriptors here are punctiform, circular, irregular, filamentous (has individual thin projections), or rhizoid (has thin,
branching projections).
- Colour
Some bacteria
produce pigments, giving the colony a distinct color. Pigments can span the
entire color spectrum. Recording the color is the first step. In addition to
describing the color, this is also the time to identify if the colony is opaque (you can't
see through it), translucent (you can see through it), dull, or shiny.
- Texture
Texture refers to
the characteristics of the colony surface. Colonies can be dry, mucoid (thick, stringy, and wet), moist, smooth, rough, rugose (wrinkled), or contain concentric rings.
- Height
The colony height, or elevation, is a description
of how the colony grows vertically. To see the elevation of the colonies, it
may be helpful to look through the side of the petri dish. The descriptors here
are flat, raised, convex (sloping up
from the edges), pulvinate (sloping steeply from the edges and
very high in the center), and umbonate (has a raised center).
- Margin
Margin describes the borders of the colony. The
edge can be entire (smooth, with no
projections), undulate (wavy), lobate (lobed), filamentous,
or rhizoid.
1) Morphology of the bacteria colonies which air is the source of contamination
A) COMMERCIAL
-
Form : Filamentous
-
Elevation : Raised,
crateriform
-
Color : Cloudy, yellow
-
Margin : Filiform
-
Surface : smooth
B) OWN PREPARED
-
Form : Circular
-
Elevation : Umbonate
-
Color : Cloudy
-
Margin : Entire
-
Surface : Rough
2) Morphology of the bacteria colonies which hand is the source of contamination
)
A) COMMERCIAL
A) COMMERCIAL
- Form : Rhizoid
- Elevation : Flat
Texture : Moist
- Color : Cloudy
- Margin : Entire
- Surface : Rough
B) OWN PREPARED
B) OWN PREPARED
- Form : Irregular
- Elevation : Flat
Texture : Moist
- Color : Cloudy
- Margin : Curled
- Surface : Rough
3) Morphology of the bacteria colonies which ear is the source of contamination
) A) COMMERCIAL
- Form : Circular
- Elevation : Raised
Texture : Dry
- Color : Buff , dull yellow
- Margin : Entire
- Surface : Skinny , smooth
B) OWN PREPARED
B) OWN PREPARED
- Form : Circular , Irregular
- Elevation : Flat ,Raised
Texture : Dry
- Color : Cloudy , Opaque
- Margin : Entire
- Surface : Skinny , smooth
4) Morphology of the bacteria colonies of which normal breathing is the source of contamination
A)COMMERCIAL
- Form:
undulate, irregular, circular
Elevation:
raised, flat
Colour:
opaque, cloudly
Surface:
smooth
B) OWN PREPARED
B) OWN PREPARED
Form:
circular
Elevation:
raised, flat
Colour:
opaque
Margin:
entire
Surface:
wrinkled, smooth
5) Morphology of the bacteria colonies which violent coughing is the source of contamination
A) COMMERCIAL
- Form : Circular , Irregular
- Elevation : Flat , raised
Texture : Moist
- Color : Cloudy
- Margin : Entire
B) OWN PREPARED
B) OWN PREPARED
- Form : Circular , rhizoid
- Elevation : Convex , crateriform
- Color : Cloudy
- Margin : Undulate
There are many different compounds that may
pollute our air at any given time or place.
Scientists and policy makers have multiple reasons for grouping these
air contaminants into specific categories. Categories may be created for
pollution regulation purposed or based on how the contaminants affect health or
the environment. Some contaminants may belong to several different categories,
creating overlap and some categories may include a few contaminants, while
others may include hundreds.
Hand is the part of the body that contact with foreign substances most frequently.Our hand will constantly come in contact with foreign substances and hence,microorganism.Sweat from hand, food leftover on hand and dead skin cells is a very good nutrient for various microorganism eg:staphylococcus epidermis and Staphylococcus aureus.Since Sir Louis Pasteur had discover that bacteria is the cause of disease,the habit of washing hand proved important in preventing disease such as diarhea.Washing hand is a mandatory practices in hospital which show that hand play an important role in spreading bacteria.Furthermore,MRSA which is a more potent variant of Staphylococcus aureus which resist to normal anti-biotic medicine,hence more attention should be paid on hand cleanliness.
The
ear is exposed to the external/outside environment. Ear wax is composed mostly
of dead skin cells and keratin with a small mixture of cerumen, sweat and oil.
Cerumen is secreted from ceruminous gland which composed mainly cholesterol,
wax esters, squalene, ceramides and triglycerides. The cerumen has
antimicrobial properties which can be attributed to its slight acidic pH 5 and
the presence of lysozyme. In normal circumstances, the ear wax is continuosly
pushed out of the ear canal by slow migration of the top layer of skin cells
from tympanic membrane towards the outer ear. The ear wax traps any foreign
particles and microorganisms. Eventhough ceruminous gland has did a great
effort to trap any foreign particles, but healthy outer ear still traps a
various type of microbes. For examples, some common bacterias like Streptococcus saprophyticum, Staphylococcus epidermis,
Turicellaotitidis, Alloiococousotitis, Corynebacterium, Staphylococcus aureus, and Pseudomonas
aeruginosa. The common fungal microbes known to reside in the ear is Candida
albicans. However, microbes that are known to inhabit in the middle ear are Streptococci,
Haemophilus pneumoniae, and Mycobacterium.
Normal breathing is typically quiet without
coughing, bubbling sounds or other noises. Human’s nose and throat contain a
lot of microbes. Alveoli contain a lot of air sacs which is used for diffusion
of air into the lungs. The surface of alveoli is moist so to increase the rate
of diffusion of air. Moisture surface of alveoli contain microbes. Microbes
will enter the nasal passage through inhalation from outside environment and
out of nasal passage through exhalation. Most of the microbes are non-pathogenic. Examples of pathogenic
microbes are Haemophilus influenzae , Staphylococcus aureus, Streptococcus
pneumoniae. Examples of non-pathogenic microbes are Neisseria, Streptococcus,
Haemophilus, Micrococcus.
Frequent coughing usually indicates the presence of a
disease. Many viruses and bacteria benefit evolutionarily
by causing the host to cough, which helps to spread the disease to
new hosts. Most of the time, coughing is caused by a respiratory tract
infection but can be triggered by choking, smoking, air
pollution, asthma,gastroesophageal reflux disease, post-nasal
drip, chronic bronchitis, lung tumors, heart failure and
medications such as ACE inhibitors. A cough can be the result of
arespiratory tract infection such as the common
cold,pneumonia, pertussis, or tuberculosis. Infections in the
breathing tubes can be caused by both bacteria and viruses, although the
most common cause in children is a virus.Both
gram-positive and gram-negative bacteria are commonly found in the throat,
including a species of fungi (Candida). The predominant microbes found in the
throat are alpha-hemolytic streptococci (viridans streptococci). The
throat is a muscular passageway which carries food and liquids toward the
digestive tract as well as air to the lungs. Because it encounters many
different kinds of objects, it’s susceptible to encounters with many organisms.
Throat's mucus funtion in facilitate food passage, but is also a way
for microbes to latch on to epithelial cells and colonize. The throat is an
excellent environment for microbes. Warm and moist, these ideal conditions
provide aerobes and anaerobes an environment to flourish. However, the throat
and tongue epithelial cells are constantly shedding, creating a complex
environment that bacteria must adapt to in order to form or maintain a
community. Violent couching is one of the way to release the microbes out of
throat and mouth.
Precaution need to be taken when doing experiment:
- Light up the flame to ensure the laminar flow on the surrounding.
- Remove the cap and pass the neck of the bottle through the flame of a Bunsen burner to sterilize it when pouring agar.
- Pass the neck of the agar bottle through the flame and recap the agar to avoid contamination of the agar.
- Do not allow any agar to splash over the side of the plate.
- We need to do movement with the shape of “8” for 5 times for the preparation of hand only.
- We cannot pour hot agar into the plate with the sample of hand to avoid killing the bacteria inside of it.
- An inoculated plate is always incubated in an inverted position to prevent condensation from falling onto the surface of the plate and interfering with discrete colony formation.
- Sterilize all work areas and surfaces before and after handling the bacteria.
Conclusion:
Microorganism such as virus, fungi, bacteria, algea and
protozoa are present everywhere and dissimenate by different bioearosol
especially wind or air stream. To prevent the spread harmful bacterias, proper
cleaning of both hands and surfaces is very important. However, not all
bacterisa are harmful; most bacterias are beneficial to us. Besides, when doing
experiments, we should always use safe techniques to deal with bacterias. In
this experiment, we have learnt that the different strains and morphologies of
different bacterias.
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