Normal and slow growth states of microbial populations in essential resource-based chemostat∗

To mimic the striking capability of microbial culture for growth adaptation after the onset of the novel environmental conditions, a heterogeneous microbial population model in the chemostat with essential resources is proposed which considers adaptation by spontaneously phenotypeswitching between normally growing cells and persister cells having reduced growth rate. A basic reproductive number R0 is introduced so that the population dies out when R0 < 1, and when R0 > 1 the population will be asymptotic to a steady state of persister cells, or a steady state of normal cells, or a steady state corresponding to a heterogeneous population of both normal and persister cells. Our analysis confirms that inherent heterogeneity of bacterial populations is important in adaption to fluctuating environments and in the persistence of bacterial infections. ∗Supported by the NSF of China No. 10601054 and FANEDD of China.