MATHEMATICAL-MODEL OF THE INTERACTIONS BETWEEN MICROCOCCUS SPP AND PSEUDOMONAS-AERUGINOSA ON AGAR SURFACE

The interactions between six different Micrococcus species and two str ains of Pseudomonas aeruginosa were studied on an agar surface. This t ype of interaction on solid surface could act as a model of situations occurring either in the environment, in food or in man. The hypothesi s of an amensalistic relationship between a Micrococcus spp. and Pseud omonas aeruginosa, due essentially to Ps. aeruginosa bacteriolytic enz ymes, is retained as the basis for a mathematical model of the variati ons of the colony surface of Micrococcus spp. (S) with respect to the distance (d) from Ps. aeruginosa cells. The diffusion of the bacteriol ytic substance in agar explains the limitation of the growth of the Mi crococcus spp. This model S = S-max (1 - e(-md2)) is shown to be adapt ed to all the interactions studied.