Prediction and Predictability of Resistance to Antibiotics: Studies based on Coupled Map Lattices

Principal Investigator: JS Shiner
Coinvestigators: M Davison, DE Uehlinger

Swiss National Science Foundation Project-No. 4049-63267, NRP "Antibiotic Resistance"

Summary

Bacterial resistance to antibiotics is a problem with many aspects: to name just a few -- the origins of resistance and the emergence of new resistant strains of bacteria, the therapeutic antibiotic regime which provides maximal benefits to patients while minimizing the threat of resistance, the development of new xenobiotics. Here we address a further important facet of the problem, one with practical implications: the spread of bacterial resistance. If a resistant strain of bacteria has emerged outside of Switzerland, can we predict if and when it will appear in Switzerland? What is the probability of appearance? What measures can be taken to prevent, or at least delay, the appearance? What roles do immigration policy and current antibiotic use play? Similar questions arise if the resistant strain has appeared in a particular area of Switzerland. Is the spread of resistance throughout the country predictable? What can be done to prevent, minimize or delay the spread? Again, similar questions arise in the hospital environment. What policies concerning isolation of infected patients and antibiotic usage should be initiated to minimize the spread of resistance throughout the hospital and to the surrounding community?

We will tackle these problems with the paradigm of coupled map lattices, which considers bacterial populations to reside on lattice sites. Sites are coupled through the spread or migration of populations from lattice site to lattice site. From studies on the effects of habitat fragmentation on population survival in population ecology we expect that the lattice configuration will have important effects on the spread of resistance. The configuration will reflect not only the distribution of both resistant and nonresistant bacterial populations but also immigration and isolation policies as well as the difference between, for example, the dispersal of bacteria within a community and the spread by long distance air travel.

Our goal is neither a detailed modelling of the spread of bacterial resistance in general nor an exact quantitative description of the spread of any one particular resistant strain. Rather we seek an understanding of how the relative fitness and growth rates of resistant and nonresistant strains, the mode and ease of dispersal of the strains, antibiotic use, and the configuration of the habitats for the resistant and nonresistant strains interact to determine the spread of resistance. On this foundation we hope to formulate general guidelines on which medical and public health authorities can base their decisions on the use of antibiotics and on immigration and isolation policies.

Some papers relating to the project

Achieving Predictability for Scale-Free and Biological Networks, by J.S. Shiner and M. Davison. To appear in Chaos, Solitons, and Fractals

Global predictability of chaotic dynamics of epidemics in coupled populations, by M. Davison, J.S. Shiner, and C. Essex. To appear in Open Systems and Information Dynamics.

Extended Entropies and Disorder M. Davison and J.S. Shiner. Submitted to Advances in Complex Systems

Peripheral vs. Central Treatment of Infectious Disease (Half written draft)