What do we bring home from school? Phase 2: A study on the role of materials and hygiene in the transmission of bacteria

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What do we bring home from school? Phase 2: A study on the role of materials and hygiene in the transmission of bacteria



This research project is the continuation of a study into the level of bacteria found in schools and measures that can be taken to reduce the transmission from person to person. This project has been carried out in collaboration with the Luxembourg Institute of Science and Technology (LIST). The first stage of the project started in 2014. It involved an examination of the bacteria found in the school. Samples were taken from various locations in the school and identified with DNA sequencing. The majority of the bacteria found were harmless and associated to the human skin " microflora ". However, Staphylococcus saprophyticus was found on the bannister (a cause of urinary tract infections). On the library table we identified Propionibacterium acnes, and a bacteria belonging to the genus Neisseria (which might provoke meningitis, a sexually-­‐transmitted disease, inflammation and other diseases). This led to a desire to study the transmission mechanism for bacteria around the school. The first experiments to test this in 2014-­‐15 did not give clear results due to a number of empirical shortcomings. Therefore, the project this year picks up the question: Do the materials we use for everyday items have an impact on the transmission of diseases? The first part of this project was to test the extent to which bacteria could survive on a range of surfaces. The surfaces tested were various soft and hard woods, copper and plastic. The outline of this experiment was to place the same amount of bacteria on each surface and see on which surface the bacteria would die the fastest. The results show a very quick death rate for the bacteria on pine and copper (nearly all gone after 15 minutes). Other woods perform better that plastic, which was the worst performer. In fact, bacteria were still present on the plastic surface after more than 10 hours. The second part of the project explored hand contact with various types of door handles (i.e. a standard lever, a long vertical pole, a flat plate, and round knob). Using invisible UV sensitive paint a group of students were asked to open a door with these various handles. The gloves used were exposed to UV light and the image of the glove was copied onto squared paper in order estimate the area where each glove had touched the door handle. These results show the greatest risk of transmission is with a normal (standard lever) door handle. This is because of the relatively high contact area when the door handle is gripped together with the small area available to hold – everybody is touching the same point. Both the plate and pole also have a high contact area with the hand but a larger area is used to touch the door, thus diluting the transmission risk. The best is the round doorknob because this is only touched by part of the fingers. While the possible area to touch is also smaller there remains several alternative ways to hold the handle. The introduction of bacteria to the school is due to a lack of hygiene by students who leave these bacteria on surfaces in the first place. In order to have more information on hygiene in our school a questionnaire was given to 50 students. While there is a general awareness of the need for hand washing, lack of time and poor facilities are blamed for not doing this more. Hand washing is particularly poor before eating and after using public transport. Finally, the potential use of hand disinfectant was tested by temporarily placing a borrowed dispenser in the entrance to the school. A number of recommendations on reducing the transmission risk of bacteria are made.

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