Optimization of a method for detection of Legionella pneumophila in water samples

University essay from Uppsala universitet/Institutionen för medicinsk cellbiologi

Abstract: Legionella pneumophila is a bacterium which can be found in fresh water and causes Legionnaires’ disease, which can be deadly for humans depending on the condition of the infected individual. The bacterium is a gram-negative rod and can withstand severe conditions such as high temperature. Therefore, various treatments including heat and acid treatment are performed on the water to inhibit interfering microorganisms. However, to examine a larger volume of water, the water needs to pass through a filter, which can be very time consuming, and there are various variables that have a negative impact on the filtration speed. The aim of this study was to examine these variables and find the fastest setup for detection of L. pneumophila. To filtrate the water, a manifold with funnels, where you put the water, is used, and the manifold is connected to a pump. Under the funnels, steel frits are placed, and the filter is placed on the steel frits. To examine the fastest setup, different manifolds, pumps, filters, and settings were investigated by timing the water running through in the different settings. A new way of sterilization, that does not damage the steel frits was tested, and the recovery of bacteria was examined on the filters with the top filtration speed. In conclusion, the most efficient setup is the Cyclopore (GE Healthcare Life Sciences) filter, the pump from KNF and the manifold MBS1 (Whatman), and the new way of sterilizing should be used to reduce the damage of the steel frits. 

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