Using quantitative models of bacterial growth, a team of UC San Diego biophysicists has discovered the bizarre way by which antibiotic resistance allows bacteria to multiply in the presence of antibiotics, a growing health problem in hospitals and nursing homes across the United States.
Two months ago, the Centers for Disease Control and Prevention issued a sobering report estimating that antibiotic-resistant bacteria last year caused more than two million illnesses and approximately 23,000 deaths in the United States. Treating these infections, the report said, added $20 billion last year to our already overburdened health care system.
Many approaches are now being employed by public health officials to limit the spread of antibiotic resistance in bacteriasuch as limiting the use of antibiotics in livestock, controlling prescriptions of antibiotics and developing new drugs against bacteria already resistant to conventional drug treatments. But understanding how bacteria grow and evolve drug resistance could also help stop its spread by allowing scientists to target the process of evolution itself.
"Understanding how bacteria harboring antibiotic resistance grow in the presence of antibiotics is critical for predicting the spread and evolution of drug resistance," the UC San Diego scientists say in an article published in the November 29 issue of the journal Science.
In their study, the researchers found that the expression of antibiotic resistance genes in strains of the model bacterium E. coli depends on a complex relationship between the bacterial colony's growth status and the effectiveness of the resistance mechanism.
"In the course of developing complete resistance to a drug, a strain of bacteria often first acquires a mechanism with very limited efficacy," says Terry Hwa, a professor of physics and biology who headed the research effort. "While much effort has been spent elucidating individually how
|Contact: Kim McDonald|
University of California - San Diego