Lab 4: Sources of Contamination and Infection

Introduction
          A microorganism or microbe is an organism that is unicellular or lives in a colony of cellular organisms. Microorganisms live in all parts of the biosphere where there is liquid water, including soil, hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are found in almost every habitat present in nature. Even in hostile environments such as the poles, deserts, geysers, rocks, and the deep sea. Some types of microorganisms have adapted to the extreme conditions and sustained colonies.
          Microorganisms are very diverse; they include bacteria, fungi, Achaea, and protists; microscopic plants (green algae); and animals such as plankton and the planarian. Some microbiologists also include viruses, but others consider these as non-living. Most microorganisms are unicellular (single-celled), but this is not universal, since some multicellular organisms are microscopic, while some unicellular protists and bacteria, like Thiomargarita namibiensis, are macroscopic and visible to the naked eye.
          Contamination is the presence of a minor and unwanted constituent (contaminant) in material, physical body, natural environment, at a workplace. An infection is the colonization of a host organism by parasite species. Infections are usually considered to be caused by microscopic organisms or microparasites like viruses, prions, bacteria, and viroids, though larger organisms like macroparasites and fungi can also infect. Infection begins when an organism successfully colonizes by entering the body, growing and multiplying.
          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 microbes are just passing through. Although they may attempt to colonize the same areas of the body as do resident microorganism, 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
Refer to lab manual


Materials and Reagents
Refer to lab manual


Procedure
Refer to lab manual


Result

Manually made culture medium agar

Bacteria colonies of air
The average of amount of the 

bacteria colonies:

=(14+12)/2

=13

Bacteria colonies of hands

The average of amount of the 

bacteria colonies:

=(468+50)/2

=259

Bacteria colonies of ear

The bacteria colonies: present

Bacteria colonies of normal breathing

The average of amount of the

 bacteria colonies:

=(17+2)/2

=18

Bacteria of violent coughing

The average of amount of the 

bacteria colonies:

=(64+62)/2

=63

Discussion

          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.
         
          We always have a certain amount of bacteria on our hands (and on our skin in general). Usually the bacteria are adapted to living on human skin and are harmless or symbiotic, 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 skin ( hands). Staphylococcus aureus forms a fairly large yellow colony on rich medium. S. aureus can grow at a temperature range of 15 to 45 degrees and at NaCl concentrations as high as 15 percent. Staphylococci are perfectly spherical cells about 1 micrometer in diameter. The staphylococci 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 middle and inner ears are normally free of microbes, but can become occupied-and infected--by persistent coughing, sneezing, and nose-blowing. These actions open the eustachian tubes, permitting microbes to enter the ears. Ear is exposed to the outside environment, despite the best efforts of the ceruminous glands, the healthy outer ear still houses a variety of microbes. The most common bacteria areStaphylococcus 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. Under normal circumstances, this bacterial flora does not thrive.Microbes are known to inhabit the middle ear are Streptococci, Haemophilus pneumoniae, Moraxella catarrhalis, and less commonly Mycobacterium. These bacteria are known to get to the middle ear by migrating through the nasophraynx and Eustachian tube.

         The conditions of the outer ear are subject to the most variation as it is exposed to the outside environment. One of the biggest effects on the environment of the ear would be those that remove the ear wax. This can occur through excessive showering or swimming as water or soap can wash away the thin protective lining of ear wax. Loss of the cerumen encourages the growth of microbes that are normally kept under control by its antimicrobial properties. Use of cotton swaps or hair pins is also common practice as a means to remove ear wax. In addition to the removal of the ear wax, they can also scratch the surface of the skin which can allow microbes to get in to the unprotected tissue. Use of cotton swabs can also push the ear wax further into the canal, which if allowed to build up can become impacted and damage the inner ear canal and the tympanic membrane. These too provide opportunities for microbes to infect the tissue. Opportunities for microbes to infect the ear diminish as the person ages. Young children with immature immune systems are more susceptible to infection by microbes than are adults with developed immune systems. Blockage of the Eustachian tube can also increase the likelihood of ear infections. This occurs when the mucus in the tube gets too thick or becomes blocked, as can occur during infections or allergic reactions of the upper respiratory tract. The opening of the Eustachian tube is also affected by head positioning. A head elevation of 20 degrees above horizontal (as can occur while lying down with a pillow) reduces the flow of air to two thirds of normal while a complete horizontal position reduces it to one third. Blockage of the tube prevents a healthy flow of mucus out of the middle ear and as a result, microbes present inside the middle ear become trapped and are allowed to proliferate.

          Normal breathing:There are many microbes live in the nose and throat, but the lower respiratory structures--the larynx (voice box), trachea (windpipe), bronchi, bronchioles, and alveoli (the microscopic air sacs in the lungs)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. One of the dangers of cigarette smoking is tobacco tar's destruction of the protective cilia, which provides a gateway  for bacteria from the nose and throat to the lungs.


           Violet coughing: The mouth harbors the most bacteria of any body part. One resident, Streptococcus mutans, causes dental caries (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. "You can carry the bug but not have decay until you eat the wrong foods," says Anne Tanner, Ph.D., senior scientist at the Forsyth Dental Center in Boston.

Conclusion
          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.
        Every human is colonized by billions of microorganisms. These microorganisms, some of ehich are vital to our well being, constitute our resident or normal microflora. Resident microorganism are nourished by chemicals and moisture excreted by the human bod. In moist areas such as the armpit, there may be one million bacteria per cm3.
        Bacteria are often known as the causes of human and animal disease. However, not all bacteria are pathogens. Bacteria put the tang in yogurt and the sour in sourdough bread; bacteria help to break down dead organic matter; bacteria make up the base of the food web in many environments.
        We also benefit from the helpful bacteria that live inside of us. It is estimated that between 5,000 and 10,000 different types of bacteria inhabit the human body. In the large intestine a complex microflora community synthesizes vitamins such as vitamin K, folic acid and biotin. Within days after birth, newborns are colonized by Lactobacilli, a group of helpful bacteria that convert milk protein to lactic acid. The bacteria remain present throughout life. These microbes are widely used in the production of sour milks, yogurt and cheese.




Reference
http://en.wikipedia.org/wiki/Infection
http://en.wikipedia.org/wiki/Contamination
http://en.wikipedia.org/wiki/Microorganism#Habitats_and_ecology
http://library.thinkquest.org/CR0212089/micr.htm
http://wiki.answers.com/Q/Do_we_have_bacteria_on_our_hands#ixzz1IFqPqcDp
http://en.wikipedia.org/wiki/Staphylococcus_aureus
http://www.suite101.com/content/normal-flora-and-opportunistic-pathogens-a93484
http://www.articlesbase.com/diseases-and-conditions-articles/types-and-prevention-of-bacteria-471084.html

http://microbewiki.kenyon.edu/index.php/Ear#Microbes_in_the_Healthy_Ear

http://findarticles.com/p/articles/mi_m1370/is_n7_v26/ai_12536154/pg_4/