engleski

Survival of Francisella tularensis subsp. novicida in different samples of water

Francisella tularensis is a gram-negative facultative intracellular bacterium that can cause a fatal disease, tularemia, in human and animals. This organism has been isolated from over 250 wildlife species, including fish, birds, amphibians, rabbits, squirrels, hares, voles, ticks, and flies. It resists harsh environments, and has been shown to survive in water and mud for more than a year. The bacterium is resistant to high temperatures of 42oC - 65oC after processing the water and food. There are several records of tularemia epidemics such as in Sweden, Spain, Finland, Kosovo and recently in Turkey, where 431 people were infected by water. There are four closely related subspecies of F. tularensis: tularensis (type A), holartica (type B), mediasiatica and novicida. The aim of the study was to follow survival of F. tularensis subsp. novicida in different water samples: non filtrate sea water, non filtrate natural water, filtrate sea water and filtrate natural water, by plate counting mothods. Our results showed that F. tularensis subsp. novicida survives in all samples of water, but the best rate of survival was achieved in filtrated natural water during 10 days of incubation. We counclude that F. tularensis survives better in filtrated samples of water due to lack of microbial biota needed for nutrition competition.

F. tularensis; survival; water; filtrated

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