Assessment of survival during starvation of Escherichia coli and Klebsiella pneumoniae in artificial urine: analysis of the kinetics of colony formation

A kinetic model of colony formation was proposed by Hattori, based on a count of the colonies that appear on a plate in successive short intervals of time. In this model, three parameters (λ, tr and N∞) are defined, which reflect the ability of a bacterium to yield colonies and allow us to described the dynamics of bacterial populations in soil and of E. coli at different growth phases. In this paper we report a reparametrization of the kinetic model of colony formation, with the aim of facilitating more accurate calculation of λ and tr. Moreover, we observed that during the starvation of E. coli and K. pneumoniae in urine, λ can be used to assess survival, since this parameter clearly decreases during starvation. Retardation time values (tr) were similar in E. coli and K. pneumoniae throughout the starvation experimental period. © 1995 Kluwer Academic Publishers.