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Urinalysis LabPurposeThe purpose of the urinalysis lab is to explore the presence of ?E. coli, Staphylococcus and Streptococcus in male and female casual catch urine samples. ?This lab also allows for practice of culture techniques used in a diagnostic laboratory. ??Challenge Option: In addition to the required hypotheses, write your own hypothesis to test and conduct an additional experiment. Assignment: Complete, highly refined lab report is DUE EOD Monday, February 16th. Background InformationWe will be testing urine samples for three different bacteria:E. coli – This bacteria is found naturally in our intestines and actually produces vitamin K and B-complex vitamins. This bacteria can also be found around the anus as it is in our feces.Staphylococcus (Staph.) – This bacteria is part of our natural flora and is found on the skin and on mucous membranes and the vagina.Streptococcus – This bacteria is also found naturally on the body and is found on the skin, on mucous membranes and the vagina.How will we know which bacteria we have?E. coli will only grow on the purple agar. The purple agar is called Eosin Methylene Blue agar and it is gram-negative. Gram negative agar will only grow gram negative bacteria. E. coli is the only expected gram-negative bacteria that we will find. If E. coli is found and it grows on the agar, it will look metallic greenStaph.& Step. will both grow on the Phenylethanol agar. This agar looks like chicken broth and is gram-positive. Both Staph. and Strep. will grow on the gram-positive agar. Both Staph. And Strep. will appear white. To distinguish between Staph. and Strep., hydrogen peroxide will be applied to the white bacterial colonies. If it is Staph., the hydrogen peroxide will bubble if it is Strep., there will be no reaction. Why does the hydrogen peroxide react with the Staph., but not the Strep.?Staph. Contains an enzyme called catalase. Catalase reacts with hydrogen peroxide to break it down into water and oxygen. Casual vs. Clean Catch Urine SamplesCasual catch urine samples are those collected without any prep of the genital area. Clean catch samples are those collected after the genital area has been wiped with an alcohol pad. Because we are looking to explore the potential for bacteria to infect the urinary tract system, we will collect casual catch samples. For this reason, our lab will not tell us if you have a UTI, the results will simply tell us the potential bacteria that can enter the urinary tract system and since are going to compare male and female samples, it tells us which gender is at the most risk of a UTI. Urinalysis Lab InstructionsMondayToday we will prepare our culture plates (the stuff our bacteria will grow on). Because we are working with microbes, which are everywhere, it is important to follow the sterile technique outlined below.Get a pair of safety goggles and put them on your face!Wash your hands!Wet a cotton ball with alcohol and draw a square on your table.Clean the inside of this square with the cotton ball and alcohol.This will be your sterile work area. Wet another cotton ball with alcohol.Pick-up your petri dishes and sterilize the outside of them.Place the dishes in your sterile work area.Wet another cotton ball with alcohol.Take the top off your petri dishes and clean the inside of your dish thoroughly, including the inside of the lid.Once the dishes are dry, use a sharpie to Label one side + and the other -. Wash your hands!Choose one partner to remain sterile. This person should stay at the work station and not touch anything until we get to step 16.Pick up the tongs and use them to pick up one test tube of agar from one of the pots at the front of the room.Hold the tube in your tongs until it is cool enough to handle with bare hands. “Flame” the tube, by swiping the opening of the tube through the open flame.With the other hand lift the lid of one of the petri dishes 45 degrees and quickly pour in the liquid agar. Immediately lower the lid and leave the dish to set. Get a test tube of agar from the other pot and hold it in your tongs until it is cool enough to handle with bare hands.Repeat steps 16 - 18 with the new tube of agar and the other petri dish.Allow your dishes to sit, undisturbed until the end of class. wash your hands!Work on writing the Title, Purpose, and Background of your lab report. These parts of your lab report should be done at the start of class on Thursday (TOMORROW). ................
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