Part 1. Introduction
1.1 Research Question
Do disinfectants - sodium hypochlorite (Bleach), Lysol©, and Allium sativum (Garlic) extract - reduce the development of evolutionary bacterial resistance in Escherichia coli (E. coli) and which disinfectant has the greatest effect on the bacteria?
1.2 Context
Other research concerning antibiotics/resistance/disinfectants
1.3 Significance
The results of this investigation has a large degree of significance to the real world. Many people use disinfectants, such as the ones used in this investigation, to clean their outside environments (the outside world) and their inside environment (their body) from the E. Coli disease. Investigating and determining which disinfectants can continually clean
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Coli and garlic to the experiment. Why them and not others. Explain that two are for outside use (to clean E.Coli) and one is for inside use (to get rid of E.Coli.) Both are to get rid of E.Coli so both types are important. Pictures.
Part II. Investigation:
2.1 Objectives of the Study
-refer back to significance. What do I want to accomplish with the results of this study.
2.2 Hypothesizes
Hypothesis 1. The disinfectants - sodium hypochlorite (Bleach), Lysol©, and Allium sativum (Garlic) extract – reduce the development of evolutionary bacterial resistance in Escherichia coli (E. coli).
Null 1. The disinfectants - sodium hypochlorite (Bleach), Lysol©, and Allium sativum (Garlic) extract – will not effect the development of evolutionary bacterial resistance in Escherichia coli (E. coli).
Hypothesis 2. Lysol© will have the greatest effect on the Escherichia coli (E. coli) bacteria.
Null 2. Lysol© will not have the greatest effect on the Escherichia coli (E. coli) bacteria.
2.3 Variables
Independent:
1. Concentration of the E. Coli bacteria on the agar plate
Dependent:
1. Diameter of the bacterial zone of inhibition
Constant:
1. E. coli Bacteria
2. Disinfectants used: sodium hypochlorite (Bleach), Lysol©, and Allium sativum (Garlic)
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Use a new cotton swabs for each plate.
7. On the Antibiotic Sensitivity Discs, use a pencil or permanent marker to label each disk with a code that signifies which disinfectant it is and which round.
a. Lysol - L
b. Bleach - B
c. Garlic Extract - G
d. Ethanol - E
8. Wrap the discs in aluminum foil and set in oven for 30 minutes and 300 degrees for sterilization.* Find source to confirm this
9. Using sterile forceps hold each disk by the edge and dip it into the respective disinfectant to be tested. Touch the disk to the side of the test tube to get rid of excess liquid.
10. Place the disk on the respective testing plate in the center of one of the quadrants. Press the disk slightly into the agar.
11. Repeat with the remaining disinfectants and the control of that round. Use the same technique for each disk.
a. Sterilize the forceps after each disinfectant and the control.
12. Incubate all of the testing plate, inverted (agar on top), overnight at 37 degrees Celsius (98.6 degrees Fahrenheit). Incubate longer if necessary if at lower temperature.
Measuring Zones of Inhibition
1. After incubation, examine the testing plates (keep covers
Three ways to assess water are positive/negative, membrane filtration and IDEXX Colilert and Enterolert assays. For membrane filtration, petri dishes and an incubator are used. For IDEXX coliert powdered medium is used for total coliform and E. Coli, while Enterolert media is used for enterococci. Also an incubator, colilert trays are used. IDEXX is more expensive than membrane filtration.
It is also important to keep learning about the new disinfectants that come out; there are constant upgrades and improvements being made with these products. There are so many different types of disinfectants so it’s important for you to choose the one that’s best suited for you. When looking for a disinfectant it’s also important to pick one that has an efficacy claim on the label. Efficacy means that it is able to produce and effect, it is also the effectiveness of the products ability to kill organisms when used correctly. Disinfectants also require upkeep; you have to be sure to change after the period of time recommended by the manufacturer. It is important to always wear gloves and safety glasses when handling disinfectant solutions. You should always keep an MSDS for the disinfectant, and always use tongs when removing items from disinfectant. You never want to let a disinfectant come in contact with your skin, if you ever do you should immediately wash with soap and warm water, rinse, and dry thourghly. Always dilute products as specified of the instructions on the label. The most common disinfectant in spas is Quaternary ammonium compounds, or “Quats”. Quats usually disinfects in ten minutes, some contain antirust ingredients so if you leave tools in the solution for too long it can cause dulling or damage. After they are in the solution for the specified time you should rinse, dry, then store in a clean, covered
“Ajax Spray ‘n’ Wipe” specifically states that it kills E. coli. This is because of the lactic acid in the spray, which is used as a natural antibacterial agent.” ("Colgate-Palmolive | Product Ingredients"). Lactic acid kills unwanted bacteria especially in food which is where E. coli is often found and transmitted, of which meat is the most common cause. Vinegar was chosen as a substance because “it can be used as a bleach alternative” (“Disinfectants: A Guide to Killing Germs the Right Way”) and bleach kills E. coli. It is also used as an everyday cleaning product. The last substance chosen was salty water because it is thought that salt kills bacteria. Much of the world’s population has access to salt and if the experiment proves that salt kills E. coli it would be a helpful factor for further treatment of the
room temperature. Vials 4, 5, and 6 should be in the bath containing water that is 10oC. After the
4.Measure 35mL of warm water and add them into each of the 4 test tubes at about roughly the same time. It is essential that the water is warm. Do not seal the test tube.
E.coli outbreaks have steadily grown over the last few decades. An expansion in big farming has led to E. coli not only being found in meat, but vegetation as well, due to waste runoff. This has increased our need for adequate antibiotics that can fight bacteria, like E. coli. The best way to pinpoint which antibiotics work is by measuring their ability to create antimicrobial agents or zones of inhibition. When a paper disc that has been saturated in an antibiotic is inserted in a solution of E.coli and medium, the zone of inhibition will be noted as the clear ring that forms around the disk. The antibiotics efficacy is then determined by measuring each disk zone of inhibition, and comparing these measurements to the zone measurements of an untreated specimen. If an antibiotic is to be deemed sufficient for treating E. coli it should show a zone of inhibition that is at least double the size of the untreated specimen.
8. With the Petri dishes on a flat surface, open sterile applicators and touch the applicators to the Agar surface to obtain a sample
Purpose: To explore the effectiveness of different levels of concentration of antiseptic and antibacterial products’ prevention of bacterial growth.
Have you ever wondered why people are always talking about E. coli, what it is, and how you can get it? What are the conditions this bacteria lives in? These interesting questions led the investigator to find out which material inhibits E. coli replication in an aqueous environment the most.
Lightly move the loop across the top of the agar to collect the bacteria. Flame the neck again and replace the cap. 5. Use the loop to mix the bacteria with the
We used forceps to dispense the antibacterial disks to the specific quadrants on each plate (refer to the lab handout to see what disks were used for each individual quadrant). We dispensed hand sanitizer on the test solution quadrant for plate 3.
Transfer the vial contents into the warmed media and centrifuge at 1000 rpm x 5 min.
Chlorine is one of the most widely used disinfectant. It is very effective for the deactivation of pathogenic microorganisms. Chlorine can be easily applied, measured and controlled. It is also relatively inexpensive.
The flaw with the design of this experiment subsists that the liquid tested (Dettol Surface Cleaner) is in fact disinfectant and not a steriliser, meaning that although it kills most germs (therefore being a disinfectant), it does not kill all germs (therefore not being a steriliser) as it has deficiencies in its sporicidal properties because it’s killing ‘techniques’ are cell dehydration, membrane disruption, and protein coagulation, these along with Hydrophilic Viruses (viruses which are mixed with another liquid, eg; water) also can also be resistant. Although E. Coli is hydrophobic, if any air transmitted viruses were to settle on the agar, the results would be extremely altered.
Re-flame the neck of the bottle and place the top on. Place the disc on section 1A of the agar plate. 3. Repeat step 2 for the rest of the petri dishes (1B, 1C, and so on) 4. Place the petri dish 1 in the incubator at a temperature of 50 degrees Celsius, and leave for 24 hours exactly.