Tuesday, October 27, 2009

Biology Assignment on Bacteria

Extended Experimental Investigation
Abstract:

The aim of this experiment was to investigate whether antibacterial soaps were effective; by inoculating petri dishes with bacteria obtained from around the classroom. A small disk, treated with an antibacterial soap was then placed at the centre of the petri dish and it was observed to see if bacteria would grow there, as this would indicate that antibacterial soaps were ineffective. After five days of observation, a circular zone became apparent around the treated disk where the bacteria had not grown. This indicated that antibacterial soaps are effective at killing and preventing bacteria for at least five days.

Introduction:

The statement that will be hypothesised in this investigation is that if an antibacterial soap is used on a surface, then it will kill and prevent bacteria from growing there. The reason that this will occur is because of the active agent in antibacterial soaps which is called triclosan, which is designed totarget a specific gene in bacteria. (M, Bond. 2002)



(M, Meade-Callahan. 2006)



Unfortunately, triclosan does not kill off all of the bacteria. It only kills weak bacteria, leaving stronger bacteria room to reproduce. (M, Bond. 2002) That is why that some members of the scientific community fear that after years of killing off the weak bacteria, all that will be left to thrive is the powerful bacteria that antibacterial agents can neither prevent nor kill. Powerful bacteria or “superbugs” as they are sometimes referred to; are theorized to have mutated and developed a resistance to these agents. (M, Brain. 2006) This is why many people maintain a belief that only sick people in hospitals and the doctors and nurses who are around them all the time (W, Mike. 2004) should be allowed to use antibacterial soaps. They hold this point of view because sick people need the extra protection from bacterial infection provided by antibacterial soaps more than healthy people who frequently use antibacterial soaps for washing and around the house. Speculation is rife that if people use antibacterial soaps all the time then there is an increased risk that superbugs could develop which would spell a disaster for the medical industry where antibacterial agents and antiseptics are being routinely used in the cleansing of skin and wound surfaces after injury, preparation of skin surfaces prior to injections or surgical procedures, and disinfection of the oral cavity. (S, Uretsky. 2006)

The two big flaws to antibacterial soaps (the first being that they only kill the weaker bacteria) is that most of the bacteria killed by antibacterial agents are harmless or actually helpful (New Book of Knowledge. 2001) Nevertheless, antibacterial soaps have been proven time and time again to be powerfully effective in preventing common infections (K, Bucklin. 2001) and at killing the three main bacteria responsible for human illness: staphylococcus, streptococcus and pneumococcus. (B, Gardner. 2006) Unfortunately, hardier bacteria such as E. Coli and staphylococcus aureus, which can be detrimental to health (E, Susman. 2002) are not as easily killed and it is these bacteria that remain on the body after a person has washed with an antibacterial soap. These stronger bacteria then have more room to grow to numbers that can have serious implications on an individual’s health. These implications could take the form of a disease, and the way that doctors today can tell if this disease is caused by a bacterial pathogen; is if all four points in the following formula; which was created by Robert Koch in the 1800s, is deemed to be true:

1. That the organism [bacteria] could be discoverable in every instance of the disease;

2. That, extracted from the body, the bacteria or germ could be produced in a pure culture, maintainable over several microbial generations;

3. That, extracted from the body, the bacteria or germ could be produced in a pure culture, maintainable over several microbial generations;

4. That the disease could be reproduced in experimental animals through a pure culture removed by numerous generations from the organisms initially isolated;

5.The organism could be retrieved from the inoculated animal and cultured anew. (B, Gardner. 2006)

Annotated Bibliography

The New Book of Knowledge. (2001). USA : Grolier
The volumes of this encyclopaedia provided detailed information about antibiotics, antiseptics and pathogens in its various forms and how to prevent them. With over 170 pages of information provided, it is obvious that this encyclopaedia has gone to great trouble to ensure that it adequately addresses the topic. All of the sources that this encyclopaedia gathered its information from were acknowledged, and the information was not bias, because it was published by a company that specialises in dealing with factual information. It was also good that this was a recent publishment of this encyclopaedia (only published five years ago) so you could be pretty sure that the majority, if not all of the information provided was not out of date.

S, Uretsky. (2006). Antiseptics (Online).
Available: Source
This website was very useful, and provided an insight into the purpose of antiseptics, as well as precautions that should be taken when using it. The information provided was of a reputable source and was impartial because the Medical Network Inc. posted it, not a drug company trying to endorse its’ product. All of the information found on this site was found to be consistent with information obtained from other sources.

E, Susman. (2002). Antibacterial Soap Overuse (Online).
Available: Source
This article was posted on MSNBC and raised that issue that washing your hands too often with antibacterial soap was not good for you. The article was written in the format of a press release and was based on numerous interviews with dermatologists who had just attended the Summer Scientific meeting of the American Academy of Dermatology. Many examples were listed and ways to improve personal hygiene were noted as well. However this site was posted by a drug company specialising in making natural alternatives to antibacterial soaps so the information was biased yet it did retain a few good points.

M, Bond. (2002). Can We Get Too Clean? (Online).
Available: Source
This article was article was written in a professional manner and contained references to other sites where the information was gathered. The report was written in a style that was critical of the use of bacterial soaps but I saw no evidence on the site as to how the creator could benefit from downplaying the usefulness of antibacterial soaps.

W, Mike. (2004) Antibacterial Soaps (Online).
Available: Source
This webpage was posted in the format of question and answer, the question being: I'm doing my science project on anti-bacterial soap and which works best. I need information on anti-bacterial soap. Do you have any or know where I can find information? The website then went on to explain in great detail the use of antibacterial soaps and how it differs from normal soap. The information provided on this site was very factual and consistent with the other sources reviewed, yet it was written in an informal manner as if to suggest a teenager could have been the author.

K, Bucklin. (2001). Antibacterial Soaps (Online).
Available: Source
This article described the life and achievements of Dr. Semmelweis who pioneered the practice of hand washing in hospitals 150 years ago. The website then went on to give examples and reasons why hand washing with antibacterial soaps was essential to health and wellbeing. This article was posted by a doctor, so it is clear that the information on this site is in the general interest of health for the reader and is not biased.

M, Brain. (2006). Is antibacterial soap any better than regular soap? (2006).
Available: Source
The author of this site has written a number of books titled: How Stuff Works and on his site, he explains how normal soaps and antibacterial soaps work and differ from each other. The facts posted on this site were consistent with the other sources reviewed and because the site was posted so recently, and updated so frequently, researchers could be assured of the up to date nature of the site.

B, Gardner. (2006). Fact and the Unusual (Online).
Available: Source
This webpage was posted to inform people of the significant contributions made by the doctors and scientists: Joseph Lister, Robert Koch and Louis Pasteur. This information was useful for the EEI because it outlined these scientist’s discoveries especially concerning bacteria. Although the site was published by a teenager, it referenced its’ points to other reputable sources and was written in a very factual manner and did not offer an opinion and therefore was not biased.

M, Meade-Callahan. (2006). The effects of triclosan (Online).
Available: Source
This website was published by a professor of microbiology so it is of a reputable source. It described in detail an experiment where triclosan’s ability to kill bacteria was tested and provided useful diagrams, such as the one included in this EEI.

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