LAB 4 : SOURCES OF CONTAMINATION AND INFECTION
INTRODUCTION
Airbourne microorganisms are usually carried on dust
particles or also may be carried by air currents. Awareness about the potential
for contamination by airbourne microorganisms is really important and carefully
observation is needed in order to reduce the risk of cultures to be
contaminate.
The body’s resident microorganism is 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 microorganism is
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 microorganisms are picked up
from the environment and usually fail to become permanent skin residents. For
example, from faecal contact. The most important reasons for failure to gain
permanence is that the established residents are better able to compete for the
nutrients.
Microorganisms in the upper
respiratory tract are either normal residents or transients. As with the skin,
the normal microflora largely consists of nonpathogen or opportunistic
pathogens. Large numbers of transients enter the upper respiratory tract when
we breathe or eat. They may also come from our hands or from improper
sanitation during food preparation.
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| FIGURE 1 |
OBJECTIVE
· To determine the microorganisms in the air and
from healthy human
RESULTS
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| FIGURE 2 : AIR |
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| FIGURE 3 : HAND |
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| FIGURE 4 : NORMAL BREATHING |
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| FIGURE 5 : VIOLENT COUGHING |
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| FIGURE 6 : EAR
DISCUSSION
Bacteria are one-celled organisms visible only with a
microscope. We can find them in the air, on food, plants and animals, in the
soil, in the water, and on just about every other surface – including our body.
Pathogenic bacteria, the harmful kind, enter the human body from the air, water
or food. Once inside, these bacteria attach themselves to or invade specific
cells in our respiratory system, digestive tract or any open wound. There they
begin to reproduce and spread while using the human body as a source of their
own nutrients and energy.
There are certain amount of
bacteria on our hands and usually the bacteria are adapted to living on human
skin and are harmless since they help to defend against harmful
bacteria. They are millions of bacteria on our hands, also fungi and
viruses. Staphylococcus aureus is the
most common bacteria found in the nose and on hands. Staphylococcus aureus forms a fairly large yellow colony on rich
medium. Staphylococcus aureus can
grow at a temperature range of 15˚ to 45˚ degrees. These bacteria are perfectly spherical cells about 1
micrometer in diameter. Staphylococcus
aureus grow in clusters because the cells divide successively in three
perpendicular planes with the sister cells remaining attached to one another
following each successive division. Since the exact point of attachment of
sister cells may not be within the divisional plane and the cells may change
position slightly while remaining attached, the result is formation of an
irregular cluster of cells.
The
outer ear is home to a varied collection of bacteria, yeasts and molds.The most
common bacteria are Staphylococcus epidermis, Turicellaotitidis,
Alloiococousotitis, Pseudomonas aeruginosa, Corynebacterium, Staphylococcus
aureus, and Streptococcus saprophyticum. The most common fungal microbe known to reside in
the ear is Candida albicans. For the middle ear,microbes that
inhibits are Streptococci, Haemophilus pneumoniae, Moraxella catarrhalis,
and Mycobacterium and these bacteria are moving to the middle ear
through nasophraynx and Eustachian tube.
For normal breathing, there are many microbes live in the nose and throat but
for the lower respiratory structures--the larynx, trachea, bronchi, bronchioles,
and alveoli have built-in barriers. The narrowing of the tubes keeps some bugs
out, and the numerous waving, hair-like cilia that fringe the cells lining the
tract propel bugs up and out.
The
mouth harbors the most bacteria of any body part. Streptococcus mutans, causes
dental cavities, but only under certain conditions. Sticky foods, such as candy
and raisins, enable the bugs to cling to teeth, where they produce acids that
eat away at tooth enamel.
CONCLUSION
Bacteria are everywhere and can spread from surface to
surface, person to person, food to food, and person to food. Harmful
bacteria can be controlled by practicing the 4 Cs of food safety. To
prevent the spread of harmful bacteria, proper cleaning of both hands and
surfaces is especially important. The good thing is that not all bacteria
are harmful; most bacteria are beneficial to us.When designing experiments, you
should always use safe techniques when working with bacteria. Also, it's
important to have a control plate. In this experiment, you also learned that
different strains of bacteria can be identified through colony morphology.
REFERENCE
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