The Important Role of Metal Ions for Survival of Francisella in Water within Amoeba Environment

Figure 2

Growth kinetics of F. novicida in water samples 1 and 2 (a) and the concentrations of manganese and zinc in the water samples during a 10 days of incubation (b). (a) To determine the growth kinetics of F. novicida, bacteria were added to the water samples at a concentration of 10⁷ CFU/ml. After 1, 3, 5, 8, and 10 days, the bacterial number in water was determined by plating the serial dilutions on BCYE agar. (b) Before inoculation of the bacteria, the initial concentrations of transition metals Zn and Mn were determined in water samples using an atomic spectrometer (AAS Perkin Elmer Analyst 200, SAD 2003). After 10 days of incubation, the samples were autoclaved, the bacteria were removed by filtration, and the soluble concentrations of remaining metal ions were determined again by an atomic spectrometer. Experiments were performed in triplicate and repeated three times. Student -test, was accepted as significantly different from control samples without addition of bacteria.

(a)

(b)