Isolation of Microorganisms Through Air Exposure and Human Skin Swabbing and Testing of Alcogel Effectiveness in Eliminating Microorganisms

Isolation of Microorganisms through Air Exposure and Human Skin Swabbing and Testing of Alcogel Effectiveness in Eliminating Microorganisms.

Abella, Angelica B.

Adviento, Audrey A.  

Arcangel, Nicholas Raphael P.

Balmes, Angela Rose A.

2Biology8, Department of Biology, University of Santo Tomas, Manila, Philippines

Abstract

Microorganisms are abundant in the environment as well as in the human body, where they perform a significant role in the maintenance of health and well-being of their hosts and the surroundings. This experiment was conducted to isolate the microorganisms in the air and in the human skin through introduction of different microbial samples to half strength Nutrient Agar and Potato Dextrose Agar media through air exposure and swabbing. Furthermore, the efficiency of alcogel in eliminating microorganisms was also tested. Contrasting results have been achieved by the different groups participated in the experiment. Bacterial growth of airborne microorganisms where lower compared to the microbial growth in plates introduced with human skin microorganisms. Lastly some alcogel samples are not effective in killing microorganisms because the microbial growth were greater than the ones with no alcogel.

Introduction

The microbial world is the largest assembly of wide variety of organisms occurring nearly everywhere in nature. They are abundant in soil, water, and air including sites that have extreme temperatures, pH or salinity. (Sherwood et al., 2014) In the 1930s, F.C. Meyer introduced the term aerobiology. This term describes a project that involved the study of life in the air. Aerobiology includes the nature of aerosols and the fundamentals of the aeromicrobiological (AMB) pathway. Aeromicrobiology involves various aspects of intramural (indoor) and extramural (outdoor) aerobiology, as they relate to the airborne transmission of environmentally relevant microorganisms, including viruses, bacteria, fungi, yeasts and protozoans. (Gentry et al., 2015)

Although atmosphere is an inhospitable climate for microorganisms mainly because of desiccation stress, Gerba and Pepper (2015) stated that, many organisms have developed specific mechanisms that allow them to be somewhat resistant to the various environmental factors that promote loss of biological activity. Spore-forming bacteria, molds, fungi and cyst-forming protozoa all have specific mechanisms that protect them from harsh gaseous environments. However, many environmental factors have been shown to influence the ability of microorganisms to survive. Two among these are relative humidity and temperature. In 1973, Wells and Riley showed the phenomenon indicating that as the relative humidity approaches 100%, the death rate of Escherichia coli increases. This phenomenon shows that high relative humidity induces death of microorganisms. At the same time, high temperatures promote inactivation, mainly associated with desiccation and protein denaturation. Therefore, as the humidity and temperature increases, the airborne organisms that are likely to grow in a certain environment decreases too. (Gentry et al., 2015)

Microorganisms are major inhabitants of our skin, mouth, and intestines. Indeed, more microbial cells are found in and on the human body than there are human cells. Furthermore, these microbes have numerous advantages to their human hosts. Some contribute to the development of the immune system of the body and help the body digest food and produce vitamins. In these and other ways, microbes help maintain the health and well-being of their human hosts. (Sherwood et al., 2014) In the human skin, there are microorganisms that are known as the normal microbiota. Microbes that do live on the skin surface are normal biota are capable of surviving under dry and salty conditions. They are rather sparsely distributed over dry, flat areas of the body, such as on the back, but they can grow into dense populations in moist areas and skin folds, such as the underarms and groin areas. The normal microbiota also live in the protected environment of the hair follicles and glandular ducts. (Cowan et al., 2013) The integument defends the body by providing a nearly impenetrable barrier. It also establishes this defines with chemical weapons on the surface. Oil and sweat glands provides a pH of 3 to 5 to the skin’s surface, which is acidic enough to inhibit growth of many pathogenic microorganisms. In addition to this, an enzyme known as lysozymes are contained in the sweat which digests bacterial cell walls. Epithelial cells also produce a variety of small antimicrobial peptides. (Losos, 2014) At a pH of 3 to 5, many microorganisms would die and would not be able to penetrate the skin but because they are capable of living at pH extremes, they will still able to evade the skin. Organisms that are able to live at a very acidic environment are called acidophiles. Some of them can even grow in acid pools between 0 and 1.0 pH. (Cowan et al., 2013)

Unfortunately, despite all the benefits microorganisms provide, they also contribute significantly to human misery as pathogens. According to World Health Organization (WHO), there are a total of ten billion new infections across the world every year. In their recent studies, four out of the top ten causes of death are clearly caused by microorganisms. This includes respiratory infections, HIV/AIDS, diarrheal diseases and tuberculosis. (Cowan et al., 2013) Because of this, controlling our degree of exposure to potentially harmful microbes is a monumental concern in our lives. Antisepsis, or what is also known as Degermation, reduces the number of microbes on the human skin. It is a form of decontamination but on living tissues. Antisepsis involves scrubbing the skin (mechanical friction) or immersing it in chemicals (or both) to destroy or inhibit vegetative pathogens. However, the efficiency of the chemicals used in antisepsis varies. Cowan, Bunn and Herzog (2013) stated some factors that affect the efficiency of these chemicals. These include the nature of the microorganisms being treated, the nature of material being treated, the degree of contamination, the time of exposure, and the strength and chemical action of the germicide.

Objectives

        The objectives of this experiment are to isolate microorganisms from environmental sources and to test the effectiveness of alcogel samples in eliminating microorganisms.

Methodology

        Calculation of 45 mL Nutrient Agar media and 45 mL Potato Dextrose Agar was done. Three plates of half strength Nutrient Agar and Three plates of half strength Potato Dextrose Agar was prepared. The media were cooled down to solidify and sterility were maintained throughout the preparation of the media.