engleski

Effect of temperature and sodium chloride on survival of Legionella longbeachae in water

Legionella species live in natural or artificially created aquatic environment and to a lesser extent in the moist soil. L. longbeachae is usually isolated from the potting mixes and compost. In our research we wanted to examine for how long L. longbeachae can survive in tap water and how different temperatures affect the survival of this bacteria. It was also tested for how long the bacteria can survive in extremely unfavorable conditions, such as distilled water and at high concentrations of NaCl. In this study, two concentrations of bacteria: 100000000 CFU / ml and 10000000000 CFU/ml were used. Bacterial survival was followed at different temperatures 4 °C, 25 °C, 37 °C, 42 °C and 55 °C. The influence of 5%, 10% and 30% NaCl was also followed. In tap water L. longbeachae survived 100 days after inoculation 100000000 CFU/ml, while after inoculation of higher dose (10000000000 CFU/ml) it survived 90 days. The temperature of 37 °C and higher (42 °C and 55 °C) has an adverse impact on the L. longbeachae. Temperature of 4 °C did not affect survival of L. longbeachae and we could isolate bacteria until the 90. day. In distilled water L. longbeachae with higher initial inoculation dose survives 90 days, while at the lower only 30 days. L. longbeachae was sensitive to high concentration of NaCl in water. It survived up to 3 days in solution with 10% and 30% NaCl and up to 7 days in 5% NaCl solution. L. longbeachae has better survival in tap water at lower temperature (4oC and 25oC) while survival was significantly reduced at 37oC and higher temperature (42oC and 55oC). High concentrations of NaCl negatively affected the survival of L. longbeachae.

Legionella; NaCl; temperature; water

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