Isolation of Microorganisms from Evironmental Samples
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University of Santo Tomas
College of Science
Isolation of Microorganisms from
Environmental Samples
Experiment 6
(Group 6)
JALIPA, Jomari T.
JAVIER, Rhea A.
JIMENEZ, Ma. Mikaela P.
JURILLA, Joaquim Gerardo L.
March 2016
ABSTRACT
The exercise aims to enumerate the various microbial species that are present in a particular environment by collecting different substances such as pond water and soil that will be the source of microorganisms to be isolated and identified. Moreover, this exercise also aims to isolate microorganisms from the environment. This will be done by exposing half-strength Nutrient Agar plates to a specific site the experimenters chose. After which, the Agar plate will be incubated and the colonies formed were observed in the laboratory.
INTRODUCTION There are approximately 10,000 named species of microorganisms. It is estimated that there are between 10,000 and 100,000 more unidentified species for every identified one (Truckee Meadows Community College, n.d.). Upon appearance, these microbes have evolved, diversified and virtually occupied every habitat possible on earth; from extreme environments to the corners of our nails, or from the deepest parts of the ocean to the tip of the high mountains. The ubiquity of these microorganisms causes them to populate in natural environments whether suspended in air, in water or associated with other organisms (ie: humans). Different surfaces whether inside or outside the laboratory can be a potential source of contamination. To contaminate is to cause accidental growth of unwanted organisms. In order to create and maintain a sterile condition to prevent contamination and accidental exposures to potential pathogens, aseptic technique must be thoroughly practiced . In this experiment, microorganisms were isolated from different areas inside the university and were cultivated inside the laboratory therefore proving their existence. Samples were also taken from the skin of different body parts. The skin is the largest part of our body and it is the most exposed part of the body, not only does it regulate the body's temperature, but it also serves as our primary defense against microbes and other elements. Some organisms have learned to live in the surface of the human skin. Such microorganisms are called skin microflora or properly known as skin microbionta (Lee, 2014). This microbial community is said to be the most diverse in the human body. Since the skin is too exposed to the environment, it is believed that the number of microorganisms in the skin is greater than a human's body cells. According to Akst (2014), some known skin microbionts are Staphylococcus, Micrococcus, Corynebacterium, Brevibacterium, Dermabacter, and Malasezzia. Skin microbes have three types depending on their location in the skin. Some grow in the forearms, hands, feet and legs. Such organisms are called (1) dry body sites and they are known to be the most diverse. (2) Moist body sites, on the other hand, prefers living in the moist part of the skin like what is implicated in the term used. Parts where to find these include elbow creases, in between groins and toes and underneath the breast. The last type would be (3) sebaceous sites. This includes the head, neck and trunk. The microorganisms living between people are typically similar but not identical. Variation is usually because of the age or the environment of those two persons (Lee, 2014). In addition, hand sanitizers of different brands were also utilized to test their effectiveness in reducing the number of microbes present in the skin. This experiment aims to enumerate the different microbial species present in a given environment and to be able to isolate different microorganisms from environmental sources.
METHODOLOGY
Six (6) ½ strength Nutrient Agar (NA) plates and 6 Potato Dextrose Agar (PDA) plates were prepared. 1 NA plate and 1 PDA plate were utilized in the isolation of airborne microorganisms. The plates were exposed in different areas of the university for at least 1-2 minutes. In our group's case, the plates were exposed inside the Male Comfort Room along the 3rd floor of the Main Bldg.
For the isolation of microbes in the skin, a sterile cotton swab and saline solution were put to use wherein the cotton swab was aseptically dipped in the prepared saline solution and was swabbed in the preferred area (sides of the mouth) and was inoculated in a plate with ½ strength NA and PDA.
A test was also performed to test the effectiveness of different brands of hand sanitizers. Here, the product was applied to one hand of a group member, leaving the other hand free of the product. Each thumb was pressed in the NA and PDA plate, lateral to each other. The plates were properly labeled and were incubated for 24 hours.
RESULTS
Group Site NA PDA
1 Female Comfort Room 0 4
2 Cafeteria 2 2
3 General education faculty 4 1
4 21 1
5 Staircase area 11 12
6 Men’s Comfort Room 0 0
7 Autoclave Room 2 1
8 Lockers 2 7
9 Carpark Multi Venture 3 4
Figure 1: Air Exposure
Group PDA (colony count) NA (colony count) Body Part
1 0 0 Face (pimple)
2 9 21 Ears
3 24 61 In between fingers
4 10 TNTC Feet (sole)
5 0 22 Behind the knee
6 0 0 Under tongue
7 66 134 Bikini area
8 TNTC TNTC Belly button
9 TNTC TNTC Nose
Figure 2: Microorganisms in Human Skin
Group Brand of Alcogel
1 Hygienex
2 Bench
3 Alcodex
4
5 Bench
6 Cleene
7 Disney (eskulin KIDS)
8 Kohl
9 Green Cross
Figure 4: Number of growth with/without hand sanitizer
DISCUSSION
Microorganisms commonly thrive on environments that are warm, wet or moist and dark. Their optimum temperature for growth is at 37 degrees Celsius, which is at room temperature. The collection of airborne microorganisms was done in different sites. It was accomplished by exposing several Nutrient Agar and Potato Dextrose plates in the chosen sites for a minute or two. Figure 1 shows the different sites chosen by each group as to where they would expose their plates. In addition, the numbers of colony that formed on the plates were noted in this figure as well. From these areas, different microorganisms were obtained and in different numbers of colony. Aside from collecting airborne microorganisms from different areas around the campus, cotton swabbing was also done to obtain microorganisms on the external parts of the human body from several volunteers in each group. Each swab was then allowed to touch the surface of the NA and PDA plates. After this, the plates were incubated inside the locker for several days. From the given results in figure 2, it can be deduced that microorganisms do not exist on abundant amounts on the ares that they were obtained from. In addition, the microbes that are present on our body are not evenly distributed as certain would normally assume. Microbes tend to thrive on external body parts that are most exposed to sweat such as the feet (sole), in between the fingers and the bikini area. Sanitizing is the removal of microbes from an object to meet a minimum sanitation requirement. Sanitizing reduces the microbial population by killing 99.9% of the targeted pathogens. Disinfecting is the total elimination of most pathogenic organisms from inanimate objects. Disinfecting provides a higher level of germ killing than cleaning or sanitizing (McFadden 2003). The use of sanitizers and disinfectants is to reduce or control the number the microorganisms we have on our body or in objects. Chemical agents that help us control the number of microorganisms we have such as quaternary ammonium compounds, phenols, hydrogen peroxide, alcohol and chlorine bleach. Cleaning products do not kill germs. They remove unwanted substances. Effective cleaning products can help control the multiplication of germs by removing their nutrient sources, but they are not germicidal (McFadden 2003). Figure 4 is a list of the brands of hand sanitizers tested by each group and figure 5 shows the number of colonies formed in each plates from the pressed thumbs (with and without sanitizers). The results show that some brands of hand sanitizer were really able to reduce the number of microorganisms while other brands had no effect.
Bibliography
Akst, J. (2014). Microbes of the skin. The Scientist
Edmonds, S.L., Macinga, D.R., Mays-Suko P. (2011). Comparative Efficacy of Commercially Available Alcohol-Based Hand rubs and WHO-recommended Hand rubs: Which is more critical, Alcohol Content or Product Formulation?. GOJO Industries, Inc. : Baltimore, MD.
Mcfadden, R. (2003). The usual suspects: Microbes, biohazards and pathogens. Coastwide Laboratories: Wilsonville, Oregon.
FDA Bacteriological Analytical Manual, 2005, 18th Ed., AOAC, Washington, DC.
Yassin, M. F.; Almouqatea, S., (2010). Assessment of airborne bacteria and fungi in an indoor and outdoor environment. Int. J. Environ. Sci. Tech., 7 (3), 535-544.
