Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Investıgatıon Of Legıonella And Free Lıvıng Amoeba In Domestıc Water Systems

Legionella bacteria are seldom in the natural environments such as soil, fresh water, lakes and streams and may pass through the man-made water systems such shower heads which are installed at hotels, houses, hospitals where they can form colonies. Legionella bacteria are phagocytosed by amoeba, that are lived biofilm layers. Therefore Legionella bacteria protected from external effects such as temperature, chlorine and radiation. Hence, it is necessary to investigate Legionella bacteria in domestic water systems which are known to cause Legionnaire's Disease and Pontiac Fever, as free living amoeba bacteria may also lead to miscellaneous infections such as encephalitis and keratitis.

In the present study, Legionella bacteria was investigated together with the presence of free living amoeba in 61 hot water and 61 swab samples obtained from shower heads in domestic water systems. Additionally the frequency of incidence of Bacillus bacteria in these water samples where Legionella bacteria did not isolated and the relationship between various features of building and water systems (age of the building, number of storey’s, age of the shower heads and their state of cleanliness, material of pipes and heating system) and microorganisms which were investigated were also studied. During the collection of water samples, relationship between the measured temperature, pH, free chlorine content and the existence of Legionella bacteria and free living amoeba was also researched.

Legionella pneumophila was isolated in 13 water samples (21.3%) out of 61 which were collected from buildings while free living amoeba was isolated in 19 samples (31%). These bacteria were determined in 12 of the water samples and in 4 of the swab samples, and eventually it has been decided to study both the water and swab samples together. However, no any meaningful relationship was determined between existence of L. pneumophila bacteria and free living amoeba in the samples. It was found that, 87.5% of the isolated L. pneumophila were serogroup 2-14 while 12.5% were serogroup 1.

It was determined that, buildings in which L. pneumophila were isolated were nearly 8-14 years old, with 7-14 storey’s, and all had water tanks and were internally furnished with ceramic wall tiles which were cleaned 1-2 times a year with hypochlorid, where as they were cleaned recently 1-6 months ago before water samples were collected. Shower heads of these buildings were 1-10 years old, and most were not cleaned at all while L. pneumophila had been grown in the showerheads which were previously cleaned. It has been learned that the pipeline of the same building was nearly 5-14 years old and the majority were made of plastic materials.

It was also determined that the buildings in which free living amoeba were isolated were nearly 5-30 years old, with 6-14 storey’s, as 5 of these buildings had water tanks and were internally furnished with ceramic wall tiles which was cleaned 1-6 months ago with hypochloride. Shower heads of these buildings were 1-10 years old and the majority were cleaned and the pipes were 3-15 years old and most of them are made of plastic materials.

L. pneumophila bacteria and free living amoeba were isolated from samples belong buildings the Asian and European districts of Istanbul.

A meaningful relationship was determined with the growing of L. pneumophila bacteria and the central heating system of the buildings while growing of free living amoeba were found in independent heating systems.

The water temperature which is suitable for the proliferation of L. pneumophila bacteria and free living amoeba was found between 45-53° C, and the pH was found 6-7 while the free chlorine content was measured between 0.3 and 0.5 ppm.

L. pneumophila was isolated in seasons other than summer, but free living amoeba were isolated at all seasons.

Bacillus bacteria was isolated in 6 of 61 buildings, and it was identified that one of the isolated bacteria was Bacillus licheniformis and 5 were Bacillus subtilis. Furthermore, it was determined that 5 of these bacteria had grown in water samples where L. pneumophila had already grown.

Consequently, it is necessary to investigate the presence of L. pneumophila and free living amoeba in water samples which were obtained from domestic water systems and also in swab samples collected from the same point. Also, there is a necessity to develop sanctions in order to control these microorganisms.