BIOS 242 Week 3 iLab: Bacterial Growth and Controlling Bacterial Growth
BIOS 242 Week 3 iLab:
BIOS 242
BIOS 242 Week 3 iLab: Bacterial Growth and
... [Show More] Controlling Bacterial Growth
Introduction
The case study I had was a 51-year old tourist arrived at the hospital in Buenos Aires complaining of nausea and severe diarrhea. Doctors found a fever of 100.2 F, pulse rate of 90, and blood pressure of 100/70. He was admitted to the hospital and placed on the IV's to replace his fluids and balance his electrolytes. Blood, urine, and stool specimens were obtained for analysis. This organism was recovered from the stool specimen. I conducted a bacterial growth test along with an OF Glucose Test with and without Oil. The purpose of these tests were to determine how the bacterium reacted to glucose with and without oxygen. My findings reported a gram stain negative along with positive tests for glucose oxidation and fermentation. The next step was an Indole production test. This test determines whether the microbe produces indole from the amino acid tryptophan. The results from this test were negative. The last test was Malonate utilization test. Which the purpose of this is to see if the microbes can be use the compound malonate as a sole source of carbon and energy of growth. Positive reaction.
Procedure: Conduct Bacterial Growth Test:
1. Click the New Unknown button. A window will open asking you to enter a label and select a subgroup.
2. Type GrowthLab1 in the “Enter a Label” line.
3. From the Subgroup dropdown menu, select Growth.
4. Click Auto-inoculation allowed and then click OK.
5. Record details of your case study scenario.
6. The Gram Stain window will open. Record results of Gram stain.
7. Include the results in your Lab Report.
Conduct "OF Glucose Test":
1. Open the Biochemical Tests Reference Book. (You can find this resource in two way; you can click on the T? button or select the Reference Books from the Help dropdown menu.)
2. Open the OF Glucose Test. Review the steps of the test and determination of test results before you begin your experiment.
3. From the Media dropdown menu, select OF Glucose Broth. The Media dropdown menu is to the far right of the New Unknown button.
4. Enter OFGlucose1 in the Medium Label window to label your sample. Click OK. Two tubes will appear. You will use the sample on the left to inoculate the sample on the right.
5. Turn on Bunsen burner by right clicking on the Bunsen burner and hitting on. You will see the flame of the Bunsen burner.
6. Select Wire from the Tool dropdown menu. Flame the wire in the flame of the Bunsen burner until it glows red.
7. Bring wire over to Inoculum sample. Right click on sample and select Inoculate.
8. Check the Traffic Signals in the upper right hand corner of the lab. Check to see that you have successfully inoculated your sample and that no contamination was introduced.
9. Turn off Bunsen burner.
10. Select Pointer tool from Tool menu.
11. Put cursor, with your Pointer tool, over your inoculated sample, drag it, and place it in the 37 degree incubator. You will also see that your inoculum sample will “disappear” from the workbench.
12. Click the New Day button. Notice that the Virtual Days counter now reads 2.
13. Put cursor over the incubator. Right click and select your sample. Your sample tube will appear on your workspace.
14. Right click on tube and select Record Results. Review the OF Glucose Test Biochemical Test information to determine if the results of the test are positive or negative.
15. When you record the results of the test, your samples will automatically be moved to the biohazard disposal bag.
16. Note the results of this test. In addition, the results from the test are recorded in the Lab Report.
Conduct OF Glucose Test with Oil:
1. For this test, you will follow the same steps as the previous test. The only difference is that you will select the OF Glucose with Oil as your medium.
2. Label your medium as follows, OFGlucose Oil.
3. Two tubes are now on your workbench.
4. Following the same steps as above, inoculate your medium. • Click Next Day. Note that the Virtual Day counter is now 3. Retrieve your sample from the incubator and record your results.
Conduct Indole Production Test:
1. Open the Indole Production Test from the Biochemical Tests Reference Book. Review the steps of this test, including that you will add Kovac’s reagent after incubating the inoculated culture for one day. Make note of how you will determine the results of this test.
2. Select Trypton Broth as your medium. Label the medium : IndoleTryptone. Click OK.
3. Inoculate your medium. Place in 37 degree incubator. Click Next Day.
4. Retrieve the sample from the incubator. To add Kovac’s reagent, select the dropper tool. Note that you can now select a Reagent (this field is now active). Select Kovacs Reagent.
5. Right click on your culture. Remove caps.
6. Place dropper above the tube opening and click your mouse. A window will open that says, Reagent Kovacs successfully added. Click OK. Note any changes in the appearance of your sample.
7. Observe and record the results.
Conduct Malonate Utilization Test:
1. Open the Malonate Utilization Test from the Biochemical Tests Reference Book. Review the steps of this test.
2. Select Malonate Broth as your medium.
3. Label sample like this: MalonateTest. Click OK.
4. Inoculate your sample and incubate for 1 day.
5. Retrieve sample from incubator. Observe and record the results.
Observations and Results
First observation was the gram stain. It was gram stain negative rods. The rods were singled and paired. The OF Glucose test came back positive for glucose oxidation and fermentation. I also noticed that none of the bacterium was eliminated as cause of the patient's illness. The Indole test was negative and that suggest the microbe did not produce indole. The bacterium was not eliminated. The Malonate utilization test came back positive and eliminated bacterium as possible causes of the illness/infection.
Discussion and Conclusion
I believe the bacteria sample is a facultative anaerobe, because of the results of the glucose test. The OF Glucose Test and OF Glucose Test with Oil tests were both positive (oxygenation and fermentation) indicating the microbe grew in both environments; with and without oxygen. Kovac’s reaction reacts with the indole indicating a positive reaction. The color change of the ring added from the reagent is positive meaning the microbe produces indole from the amino acid tryptophan. The ring turns a cherry red if positive, and yellow or amber if negative. The bacteria did grow in the Malonate media. This is because the microbe was able to use malonate as a sole source of energy and growth. The media for the OF Glucose test was synthetic. The media used for the Malonate test was selective, due to the salt content and the elimination of staphylococcus and streptococcus. The Indole test was differential because the bacterium became acidic, indicating a red (positive) reaction. At the end of the tests, there were 25 bacteria remaining. The bacteria which caused the infection was Shigella Dysenteriae. Some of the additional tests that could be ran to help determine the agent could be Sorbitol Fermentation, Sucrose fermentation, Hydrogen Sulfide, Lactose fermentation, and several more. Understanding how each bacteria reacts to tests is a very important tool to have when taking care of people.
Experiment II: Controlling Microbial Growth
Introduction
The resort owner worried that his profits would evaporate as his normally placid lake became the site of the modest fish kill. The sight and smell of rotting fish could not be good for business. He called the department of fish and wildlife to investigate. This organism was isolated from the water and decaying fish.
Procedure
1. Click on New Unknown button.
2. Type GrowthLab2 in the label field. Select. Controlling Growth from the subgroup dropdown menu.
3. Click Auto-inoculation allowed. Click OK.
4. Record details of your case study scenario.
5. Record gram stain results of the organism.
6. No further tests will be performed. You will answer questions about this topic in your final lab report. See below.
Observations and Results
The gram stain results are a gram positive cocci. They were purple in color which means they are positive and in cocci shape. The cocci grouped together throughout the stain.
Discussion and Conclusion
Since all living things need water in order to survive, reducing it prevents any living thing from growing. Salt kills microbes by a hypertonic solution. Most microbes will swell and burst due to the solution on the outside becoming higher. Malonate and Indole both have increased concentrations of salt. Salt is used to preserve and prevent spoilage by drying out the food and killing the microbes. Bile salts exert antimicrobial activity by reducing the amount of water which is required for all living things. Salt also breaks down the digesting by using acid, which could cause harm to the bacteria. If the concentration of bile salts is 10%, the esculin agar would be 0.1%. Some bacterium may be able to grow on this medium if they are hypotonic, and require little water. Nitrate inhibits anaerobic growth because it suffocates the microorganisms during the reduction of nitrates to ammonia.
Conclusion
Easiest of the labs so far for me because it had the least steps. It was not hard to identify the gram stain. The lab was overall a success. [Show Less]