engleski

Survival of Francisella novicida after exposure to drying and different growth conditions

Francisella tularensis is a gram-negative facultative intracellular bacterium that can cause a fatal disease tularemia, in human and animals. The genus Francisella contains five species: F. tularensis, F. philomiragia, F. hispaniensis, F. noatunensis and F. novicida. The bacterium has been isolated from wide variety of organisms including fish, bird, rabbits, squirrels, hares, flies and amoebae. It has been speculated that bacterium can persist in the environment without the presence of a suitable host. In this study we investigated the internal and external factors that influence the survival of F. novicida in vitro. The survival of F. novicida was followed after growing the bacteria in buffered yeast extract (BYE) broth with standard concentration of L – cysteine and α – ketoglutarate as well as in BYE broth where concentration of L – cysteine and α – ketoglutarate were changed. Further, the viability of F. novicida was observed after exposure of bacteria to air drying during 60 seconds, 30, 60 and 90 minutes followed by recovering in D. discoideum cells. The growth of F. novicida was significantly enhanced in the presence of high concentration of L – cysteine and α – ketoglutarate in BYE broth. Bacteria exposed to air drying over 60 seconds was able to recover in D. discoideum cells, but the longer periods of drying resulted in damaging the cell viability.

Francisella; drying; L-cysteine; α–ketoglutarate

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