Microbiology assignment PDF

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Microbiology: Task 3: Controlling microorganisms a.) Laboratory aseptic technique: Laboratory aseptic technique is a technique to reduce the likelihood of bacterial contamination. Microbiologists use aseptic techniques for various procedures including using cultures. The first step is to: disinfect the work bench with a chemical called Virkon, before and after procedure. Then to minimise the access and entry of bacteria through airborne that has been exposed to bacteria. This is due to opening the petri dish to spread the microorganism. Therefore, it is important to open the lid at the shortest time possible. Flaming is to kill bacteria around the environment to prevent it from entering the petri dish when the lid is open. As a result, the distance of the flame from the bunsen burner should be 3 petri dishes away. The bunsen burner flame has to be set at a blue flame because the flame is a thermal convention that stops spores and bacteria from growing. b.) Vector control: Vector control is a method to prevent malaria and the spread of malaria. Examples of vector control: long-lasting bed nets, indoor/outdoor spraying of pesticides, eliminating breeding sites and sterilizing the mosquito. Eliminating breeding sites means removing sites where drinking water is collected, such as water barrels or water streams. This is because the water could be contaminated from mosquitoes laying their eggs in the water and it can spread malaria due to the parasite in the eggs. Sterilising the mosquito is the outcome of genetic engineering. It works by sterilising male mosquitoes and they are released into the environment, so they can mate with female mosquitoes. Which results in the eggs released from the female mosquito to be infertile- won't be able make eggs and spread malaria. Therefore, these are the most important vector control measures that help to protect individuals from the malaria parasite that is carried by mosquitoes and given through bites. Vector controls works by controlling the population of mosquitoes. Reference: https://www.who.int/malaria/areas/vector_control/en/ : assessed 20/11/18 c.) Alcohol based hand gels: These hand gels are made with 70% alcohol and alcohol kills bacteria, so 99% of bacteria is killed through the use of hand gel. Therefore, it works due to alcohol (ethanol) killing the bacteria on the hands through protein denature and dissolves the membranes. It is more likely to work due to the concentration of alcohol, and it is dependent on the quantity of the hand gel used. This is because small amounts of hand gel makes it less likely for the alcohol to kill most of the bacteria. As a result, if the hand gel evaporates quickly it won't work because the alcohol was unable to denature the protein.

d.) Antibiotics: Antibiotics work by fighting bacterial infections by killing the bacteria in the body. For example, Penicillin. Penicillin is an antibiotic that stops the growth of a bacterium's cell wall. This is because when bacteria grows making an individual feel sick, the antibiotic will weaken the cell wall by making it become thinner and it will eventually burst open- which will kill the bacteria. However not all antibiotics, such as tetracycline kill bacteria but decreases the growth of it by terminating the protein synthesis. Antibiotics can either: broad spectrum, kill a range of bacteria or narrow spectrum, kill a specific type of bacteria. e.) Autoclaving: Autoclaving is used for the sterilization of materials and equipment in an autoclave. For example, a class of students experiment with E.Coli and use a Petri dish to collect the bacteria so they can measure the amount of growth. Therefore, microorganisms would have grown and the Petri dishes are needed for the next class, so putting the equipment in the autoclave will destroy the microorganisms. Autoclaving kills the microorganisms, living organisms and spores by using high pressure of stream at a high heat of 27 degrees for 25 minutes. f.) Radiation: Irradiation is the process by which an substance or organism is exposed to radiation. Gamma rays and UV light are a high energy source with electron beams. Therefore it causes mutations in cells, such as bacteria and the radiation can control the growth of cells by breaking chemicals bonds in molecules that are important for cell growth. This results in the bacteria dying. Radiation can also be used at an appropriate level to sterilise objects, such as medical instruments and food. g.) Vaccines: Vaccines provide immunity to a disease by stimulating the production of memory B cells and antibodies. Therefore, vaccines can be used to prevent infections in the future or to cure individuals. A vaccine includes small amounts of the microorganisms causing the illness. For example, killed microbe is a type of vaccine that contains inactive microorganisms that have been killed from the use of chemicals. Vaccines work by making the body to believe that is already infected with the disease. This is because the body starts to an immune attack which means it's a primary response. The immune system will overcome the weakened strain of the disease, create specific antibodies and memory B cells. So, if in the future an individual contracts the disease again the body will remember how to defeat it due to the B memory cells that were created when they were vaccinated and release antibodies that were stored by the body.. Therefore, the immune system will be able to respond quicker which is called the secondary response.

Part 2: Effectiveness of Control methods Experiment 1: Antibiotic sensitivity (chemical method):

In this experiment, I investigated the effectiveness of antibiotics in controlling the growth of E.coli. My results tell me that Oxacillin, Novobiocin, Penicillin and Streptomycin had no effect on the growth on E.coli. Whereas, Chloramphenicol, Erythromycin, Fusidic acid and Tetracycline had a 10mm effect of the growth on E.coli. Before the experiment, I expected Penicillin to effect the growth on E.coli because it is a antibiotic used in medicine to treat sick individuals by weakened the cell wall of the microbe and eventually killing the cell to stop the growth. I believe, that Penicillin and the other antibiotics that did not work was due to human error- the antibiotic mast ring was not placed correctly onto the agar plate; I wanted to finish my experiment quickly. Therefore, in the future to avoid making the same mistake I should take my time when placing the mast ring to avoid interfering with the results. Experiment 2: Disinfectants (chemical method): In this experiment, I investigated the effectiveness of antimicrobial inhibitors controlling the growth of E-coli. Looking at my results for the effectiveness of the antimicrobial inhibitors plate, I tell that bleach and virkon had the most effect of growth on E.coli. This is because bleach’s effect on E.coli was 6mm and Virkon’s effect on E.coli was 6mm. Whereas, water (H20) had the least amount of effect on the growth of E.coli with 0mm. Detol had the second least effect because it was 2mm. Therefore, Bleach and Virkon killed the most cells and Water killed the least. I expected water to not have a big effect on the growth of E.coli because it has a neutral PH balance and I expected the results from bleach because it contains chemicals, such as acid which is low in PH levels. However, water may have had no effect because I could have put a small amount onto the agar plate which means that there was not enough substance for the water to control the growth of E.coli. Experiment 3: Salt concentration (chemical method); In this experiment, I investigated the the use of salt (chemical) to control the growth of microbes, such as E.coli. Therefore, looking at my results I can tell which percentage of salt was most effective and least effective. 0% of salt had quite a lot of growth and the growth was in layers. 0.5% of salt had a lot of growth and was also layered. 1% of salt showed a lot of growth grouped in cells that covered the agar. 2.5% of salt had a lot of growth and the growth was also layered on the agar plate. Lastly, 5% of salt had a lot of layered growth. My results tell me that 0% of salt had the least effect on the growth of E.coli compared to the other percentage of salt. 0.5%, 1%, 2.5% and 5% had similar results. I expected 5% of salt to have the most effect in controlling the growth because it had the biggest salt compared to the others. Experiment 4: Ultraviolet light (radiation method) In this experiment, I investigated the use of radiation to control the growth of E.coli. My results tell me that the highest minute, which was 2 minutes, that was exposed to UV radiation had the least effect on the growth of E.coli. This is because at 2 mins the cells were already killed, so there was no growth present. Whereas, in 0 seconds there was a lot of growth on the agar plate. 10 seconds had quite a lot of growth, 20 seconds had little growth and 1 minute had little

growth, the growth was in colonies. So, this means that as time increased the more bacteria was killed- became inactive and had less growth. I expected these results because the more exposure to the UV light would mutate the cells and radiation is able to control the growth of cells by breaking chemicals bonds in molecules that are important for cell growth. Therefore, it explains why at 2 minutes there was no growth and at 0 seconds there were a lot of growth. Experiment 5 (1): Temperature control (temperature method) This was the first experiment I did and it was about using temperature to control the growth of microbes. I investigated the effectiveness of heat (high temperature) and freezing (low temperature) in controlling the growth of E.coli. My results tell me that 5 seconds of heated time had quite a lot of growth and it grew in layers. 10 seconds of heated time had quite a lot of growth. 20 seconds of heated time also had quite a lot of growth. Whereas, in 30 seconds of heated time it had a lot of growth. The results for 30 seconds of heated time had the most effect on the growth of E.coli compared to the other times. However, it would have been normal by 30 seconds of being in the microwave, have little growth or even no growth but Mark (teacher) had set the power to low which interfered with the final result. So, before the experiment I would have expected 30 seconds of heated time to have no growth because when microbes are heated they are killed, no longer active. I also investigated the low temperature and my results tell me that at frozen there was some growths that had affected the growth of E.coli and conditions at 0 had quite a lot of growth. Therefore, this shows that cells are not killed in cold temperatures. Part 3: Analysis of control methods. The Ebola 2014 Outbreak Ebola is a virus and deadly disease that originated in Central Africa. The symptoms consist of a sudden high fever, weakness, muscle pain and a sore throat. However, as the disease worsens so does the symptoms. These symptoms at the subsequent stages are committing, diarrhea and sometimes both internal and external bleeding. The infection is caused by the Ebola virus fusing within the cells lining the respiratory tract, eyes or body cavities. The virus’s genetic information are released into the cell and the virus replicates itself. Therefore, new copies of the virus are made and released into the body’s system. The virus then spreads to people through physical contact including hugs, handshakes, kisses and healthcare workers from other infected people and animals, such as chimpanzees. It can also spread by direct contact with infected bodily fluids and move from person to person and contaminated environments like a funeral where people have died from the disease. That's why it is vital for infected dead bodies to be treated carefully. Dead bodies must be treated with care because of their high viral load. For example, blood from external bleeding is a symptom of the Ebola virus which causes death. So, individuals that come into contact with blood or other bodily fluids are at a risk of being infected. People who are at the highest risk from the infection are healthcare workers that treat infected patients and people from West African countries due to practices with religion and contact from ritual preparation of bodies includes washing and kissing. Therefore, individuals who handle the body and come into close physical contact with the blood are at a highest risk from the infection.

The last major outbreak to date was in 2014 and it was different to control the spread of infection because citizens were unknowingly eating wild bushmeat that were infected with the disease. As bushmeat is a delicacy in some parts of West Africa it was also the cause of Ebola. As large amounts of people were suffering from the disease, healthcare professionals such as doctors and nurses were needed to treat patients. They would have eventually contracted the disease due to poor environments and died. Therefore, more healthcare professions would be needed and it became difficult to control because healthcare professionals would consult family members and spread the virus. Another reason why it was hard to control the disease is due to poor sanitation and poor hygiene due to lack of resources from third world countries. Handshakes and hugs are part of African culture and it would be easy to spread the disease from person to person. A strategy I would put in place to control the spread is to develop funeral capacity, so deceased people can be buried in a safe place and respectful manner. It would reduce the amount of people contracting the disease in an unsafe environment from bodily fluids because it would limit families from performing ritual preparations of bodies. However, my strategy may fail because it is part of some West African culture for bodies to be washed, touched and kissed. It would seem disrespectful to restrict families from preparing a peaceful send off for their deceased loved ones. Therefore, it could lead to families preparing unsafe burial services which will increase their risk of contracting the Ebola virus due to close physical contact. Another strategy I would put in place to control the spread is providing education, so people know how to use protective equipment and become aware of the risks of Ebola. This is because, an individual educated on the Ebola virus would know not to use shared towels, regularly washing their hands and improving their hygiene; they would be at a lower risk of contracting the disease. Communities should be educated on the risks of consuming bushmeat and contact with infected fruit bats and monkeys. However, bushmeat is considered a delicacy in some African countries which may cause this strategy to fail. This is because there could be limited resources in food and individuals may have to result to bushmeat as it may be easy to access due to being sold as street food. Another strategy I would put in place to control the spread is improving the work environment for healthcare professionals. This is because a percentage of health workers die treating infected individuals and spread it to individuals who receive consultation. For example, an individual may visit a doctor who has been in contact with infected patients because they believe they have the symptoms of the disease. However, this strategy may fail because large amounts of infected people will seek a doctor and if doctors are understaffed they may find it hard to keep the environment safe and clean by wearing face masks all the time and being exposed to infected blood. Reference: http://apps.who.int/iris/bitstream/handle/10665/163360/9789241508698_eng.pdf;jsessionid=463 199035D53D2985A02D63C04030D27?sequence=1 assessed 21/11/18

http://www.bbc.co.uk/news/world-Africa-26835233 assessed 21/11/18...