engleski

The influence of metal ions on the growth of Francisella novicida in water

Francisella tularensis is a gram-negative facultative intracellular bacterium that resists harsh environment. It has been shown that bacterium is able to survive in water and mud for more than a year. Several epidemics of tularemia have been connected through transmission by water including the recent one in Kosovo and Turkey. Our previous results showed that F. novicida survives in natural spring water („Vela Fontana“ from the island of Krk) which contained high concentration of manganese ions. The aim of this study was to determine the effects of different concentrations of Fe, Zn and Mn ions (0.1 μM ; 0.8 μM ; 0.1 mM ; 0.5 mM and 1.0 mM) on the growth of F. novicida in ultra pure water by CFU. In addition, the concentrations of metal ions in water were determined by atomic spectrophotometer. The results from this study show that the best growth of F. novicida was achieved in water supplemented with Mn ions. The growth rate of bacterium was not dependent on the Mn ion concentrations. In contrast, the concentrations of 0.5 mM and 1.0 mM of Zn ions decreased the growth of F. novicida in water while the the concentration of 0.1 μM and 0.8 μM of Zn ions increased the growth of bacterium over time. Similar, the highest concentration (0.5 mM and 1.0 mM) of Fe ions in water decreased the growth of bacteria. However, the concentrations of 0.5 mM and 1.0 mM of Fe did not influence the growth of Francisella in water. To conclude, the growth of F. novicida is enhanced when the water contains the Mn ions.

F. novicida; ions; water

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