Codice  QDD 136 
Titolo  Persistent and susceptible bacteria with individual deaths 
Data  20121029 
Autore/i  Zucca, F. 
Link  Download full text 
Abstract  The aim of this paper is to study two models for a bacterial population subject to antibiotic treatments.
It is known that some bacteria are sensitive to antibiotics. These bacteria are in a state called persistence and each bacterium can switch from this state to a nonpersistent (or susceptible) state and back.
Our models extend those introduced in [6] by adding a (random) natural life cycle for each bacterium and
by allowing bacteria in the susceptible state to escape
the action of the antibiotics with a fixed probability
1p (while every bacterium in a persistent state survives with
probability 1). In the first model we inject the antibiotics in the system at fixed, deterministic times while in the second one the time intervals are random.
We show that, in order to kill eventually the whole bacterial population, these time intervals cannot be too large . The maximum admissible length is increasing with respect to
p and it decreases rapidly when p<1.
While in the case p=1 switching back and forth to the persistent state is the only chance of surviving
for bacteria, when p<1 and the death rate in the persistent case is positive then switching state is not always a good strategy from the bacteria point of view.

