ABSTRACT

In our daily life, bacteria are virtually ubiquitous. They are everywhere. They are in air we

breathe, the food we eat and the water we drink. The objective of the experiment is

determining the effects of various environmental exposures to the sterile bacteriological

media. The methodology employed is swabbing the sample and transferring in to the agar

medium. At the end of the experiment, it is observed that the bacteria are most abundant on

the sole of the shoes compared to the body sample. There are many colonies of bacteria with

difference sizes, shapes and margin in the sole of the shoes. In conclusion, bacteria are

present everywhere.

INTRODUCTION

Microorganism or microbe is an organism that is microscopic which mean too small to be

seen by the naked eyes however visible under the microscope. For instance bacteria, fungi

and protists are classified as non-living microorganisms but not viruses and prions. The term

ubiquitous means found everywhere, therefore the ubiquity of microorganisms is the concept

that microorganisms can be found everywhere. Besides, microorganisms can be found in

wide variety of environment like in air, on land, plants, animals and in fresh or salt water

environments. Bacteria able to live everywhere because they are all well adapted to all

different type of environment and can colonize that particular environment. For example,

according to Oracle Think Quest Education Foundation, it stated that Cyanobacteria Nostoc

lives on the land and forms in filaments of hyphae that hold the microbial mat of lichen

together.

In microbiology lab, lots of time and energy is spent in order to culture the desired microbes.

Therefore to obtain pure cultures from these mixed colonies in the environment, we used

streak plate technique to obtain pure culture from sole in foot. Microorganism from mouth is

obtained from coughing at the surface of agar plate and at the shoe sole. There are two forms

of bacteriological media will be used to culture the microorganisms which are agar medium

and broth medium. The only difference between those two is the presence or absence of the

complex polysaccharide called agar, a solidifying agent purified from red algae. Agar-agar is

not a nutrient because it contain 1.52% agar for the solidified media so giving a solid surface

for the bacteria to grow on and could not be utilized by the organisms. Meanwhile the

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presence of bacteria will produce turbidity in broth culture. A mixed culture from most of

specimen can be seen based on different colony sizes, shapes, colours and many more.

OBJECTIVE

1. To compare the growth of bacteria from different environments.

2. To identify the ways that bacteria grow on and in bacteriological media.

3. To become accustomed with different type of media.

THEORY

The term ‘ubiquity’ of microorganisms can be defined as everywhere. That means,

microorganisms can be found nearly everywhere on the planet. Microorganisms include

bacteria, archaea, algae, protists, protozoa and viruses. According to Hans G. Schlegel and

Holger W. Jannasch (2006), the three major factors that contribute to the ubiquity of

microorganisms are their small size that can be dispersed easily by air and water, their

metabolic versatility and flexibility, and their ability to tolerate the unfavorable conditions.

For example, some archaean can live in hot spring rich in Sulfur.

Besides, microbes especially bacteria are widely distributed in the human body and on

surfaces of any materials and tools. Therefore, to understand the concept of ‘ubiquity’ of

microorganisms, an experiment should be conducted by taking the specimen from the body

and from the environment. In this experiment, the body sample was in the form of a cough,

and the environmental sample was taken from the sole of a shoe. Bacteria can be spread

through coughing, because according to Marshall Cavendish (2008), they are often present in

saliva, in the mucus from the nose and lungs which can be sent through an airborne manner.

On the other hand, there were many bacteria which were picked by shoes when walking. This

is because, the bacteria that is already present on the soil, toilet floor tiles and on the road or

any surfaces that we step on are transmitted to the shoe soles as we are walking on them.

Culture media Trypticase Soy Agar (TSA) and Trypticase Soy Broth (TSB) are used to

isolate and observe the growth of bacteria. These media contain casein and soy products that

support the growth of almost all microorganisms, and is a general purpose agar of sorts.

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After incubation for 24 hours, the colonies of microorganisms are visible to naked eye.

Therefore, the general form of the colony and the shape of margin of the colony could be

determined by looking at the top of the colony while the elevation of the colony could be

determined by looking the view side of the colony at eye level as below:

Adopted from Microbiology (First Edition), 2003

Figure 1: Variation in microbial colony seen with naked eye

APPARATUS AND MATERIALS

2 bottles of Trypticase Soy Broth (TSB)

2 Petri dish of Trypticase Soy Agar (TSA)

Sterile Cotton Swab

Laminar Flow Cabinet

Incubator

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PROCEDURE

Note: Aseptic techniques were applied throughout the process of this experiment. (Procedure

was performed in the laminar flow cupboard.)

A. Isolation of Bacteria from the Environment.

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Firstly the bottom of TSA plates and also TSB bottles were labeled with our group name and

source of our specimen.

Secondly, the environmental specimen which was from the sole of the shoe was collected

using a sterile swab by rolling it around the sole.

The swab was then placed into the TSB and swirled around. The bottle was recapped.

Lastly, the result obtained was recorded and analyzed.

The agar plate and universal bottle containing the sample was incubated for 24 hours.

Next, the swab was rubbed on an agar plate in a zig-zag pattern. The Petri dish was closed.

B. Isolat ion of Bacteria from the Human B ody.

RESULTS

Sample Agar Plate Agar Broth

Body - Cough

Environment- Shoe Sole

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Firstly, the bottom of TSA plates and also TSB bottles were labeled with our group name and

source of our specimen.

Next, one of our group member coughed on the surface of agar plate and also into the

universal bottle.

The agar plate and universal bottle was incubated for 24 hours, along with the environment sample.

The results were recorded.

DISCUSSION

Figure 2: Types of colony morphology

After landing on the agar plate, a bacterial cell will divide and continue to divide until it

forms a mound or pile of bacteria known as a bacterial colony. It is known that different

species of microorganisms are represented by different colonies with different visual

characteristics. Colony morphology includes the size, color, overall shape, elevation and the

margin of the colony (Engelkrik, 2008).

In our experiment, the sample from the body was a cough. In the results, there was no growth

on the solid agar surface, however very small particles were seen to be suspended in the broth

medium. We pin this on the fact that our sample was not collected efficiently as we did not

cough hard enough for any bacteria to be released.

There was no sign of any growth on the agar plate whatsoever. This does not correlate with

the theory that bacteria is spread every time a person coughs. However, it is believed that the

method for collecting the sample was not carried out correctly. The collection of the sample

involved placing the Petri dish in front of the face, and coughing several times into the plate.

It might have also been the fact that none of the samples taken were from an ill person,

therefore less bacteria was able to be transferred.

The sample from the environment used in our experiment was a sample from the sole of a

shoe. The resultant agar dish showed various types of colonies of bacteria, with different 6

shapes, sizes and margins. The results showed colonies with that were circular, irregular and

also rhizoid shaped. The margins for the colonies were entire for circular colonies, lobate for

irregular colonies and filamentous for rhizoid colonies. Some colonies flowed into each other

and were a combination of either irregular and smooth, or irregular and rhizoid. There were

also colonies which had a very cloudy and unclear margin, and this was chosen to be

classified under irregular colony shape, and undulate margin. The elevation of the colonies

were not visible, as all the colonies looked to be only slightly raised compared to the agar

surface, and no colonies had a distinct elevation type to be characterized by it. The different

types of colony suggest that there are many types of bacteria present in the agar plate, as

mentioned before, different bacteria give rise to different colonies, and thus have different

morphologies. The distribution of the colonies in the plate was random, and had no structure

within the entire plate, where colonies with similar characteristics being situated at opposite

ends of the plate being observed.

The reason both agar plate and agar broth were used was to observe the difference in the

bacterial growth between the two media. What was observed in the agar plates for the sample

from the sole of the shoe was that the colonies were relatively large and non uniform, as there

were many different bacteria present. However, in the case of the sample from the sole of the

shoe in the agar nutrient broth, the bacterial colonies were very small and plentiful, as well as

suspended in the broth. We suspect this is due to the fact that much of the bacteria from the

sample was already spread on the agar plate, and there was not many bacteria left of the

sterile swab, when we immediately dipped it into the nutrient broth. However, we did get a

positive result for microbial growth, indicating that bacteria do inhabit the soles of our shoes.

CONCLUSION

From the results of the experiment, it can be concluded that bacteria are ubiquitous. The

bacteria are most abundant on the sole of the shoes compared to the body sample. There are

many colonies of bacteria with the different shapes, sizes and margins on the sole of the

shoes, which is expected as shoes are used to walk in many places. Different places have

difference kind of bacteria. In the plates, colonies are more distinct and are much clearer and

more visible than the bacteria that grow in the broth medium. The objectives of the

experiment were met.

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RECOMMENDATION

Firstly, the correct technique of coughing is needed to improve so that we can get the

bacteria. Secondly, the technique of swapping the sole of the shoes must be correct, swap all

the area of the sole. Thirdly, the procedure needs to be improved. For the body part, put in the

incubator while for the environment, put in outside the incubator.

REFERENCES

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Erko Stackebrandt. 2006. The Prokaryotes (Third Edition). A Handbook on the Biology of

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3. N. P. Saxena and D. K. Awasthi. 2003. Microbiology (First Edition). Methods for

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World Wide Web: http://web.clark.edu/tkibota/240/Lab/M1_Ubiquity.pdf

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from World Wide Web: http://library.thinkquest.org/CR0212089/micr.htm

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Essentials of Diagnostic Microbiology. Lippincott Williams & Wilkins. p198

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