Identifying An Unknown Bacterium Broth Culture

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In class, we were given the task of identifying an unknown bacterium broth culture. After receiving number 69, I went through several tests to figure out what bacterium I received. First, I created a slide from my broth by putting a small amount of the unknown broth on to a clean slide and letting it dry for ten minutes. After this, I stained the slide by applying four reagents in order; crystal violet, grams iodine, decolorizer and safranin. From the stained slide, I discovered that this bacterium was gram-negative, which would determine the next couple of tests I would do to identify my unknown bacterium. I began by streaking for confluent growth from my broth culture onto a TSA plate. From the TSA plate, I aseptically transferred a loop…show more content…
E. coli are usually harmless, but can cause urinary tract infections, respiratory illnesses and other illnesses. This bacterium is also beneficial to humans and are part of our natural intestinal microflora, but E. coli can also lead to mild to serious illnesses in the human body. Disease causing E. coli are grouped according to the ways they cause illnesses. Escherichia coli is spread when people consume at-risk foods, these include foods such as undercooked ground beef, produce that have come into contact with fecal matter, contaminated water and unpasteurized dairy and juice products. This bacterium can also spread from person to person by unwashed hands, contaminated surfaces (fomites) and pond water. Furthermore, dangerous strains of E. coli, such as E. coli O157:H7, produces toxins such as Shiga toxins. These toxins have the capabilities to damage the lining of the small intestine, which can result in stomach cramps, diarrhea, vomiting, nausea and bloody stool. If a person can come into contact with a contaminated source, symptoms can appear about three to four days after exposure and can usually last between one to nine days. The infected host is considered contagious until their symptoms stop and even a couple days after that. The way E. coli O157:H7 is diagnosed is by a special stool culture that is sent to a stool laboratory, where tests are run to
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