Varying Drug Levels in the Body Could Speed the Emergence of Drug-Resistant Bacteria
Posted Jun 19 2012 5:35pm
Scientists led by physics professor Terence Hwa at the University of California, San Diego, thought that the variety of environments in which bacteria encounter antibiotic drugs could play an important role. They have developed a mathematical model, published in the June 18 early online edition of the Proceedings of the National Academy of Sciences, that demonstrates how that would work.
Drug levels can vary widely between different organs and tissues in the human body, or between different individuals in a hospital. To account for that, their model considers a matrix of “compartments” with differing concentrations of a drug.
Snapshots from the model of evolving antibiotic resistance show a population of bacteria simultaneously expanding and adapting to antibiotic drugs, leaving a “comet tail” of less-resistant bacteria behind.
The bacteria in their model can move randomly from one compartment to the next. Their survival and rates of proliferation depend on the concentration of antibiotic within each compartment. And mutations that allow the bacteria to survive and thrive in environments with slightly higher concentrations were allowed to emerge randomly as well.