HOUSTON -- (Sept. 21, 2009) -- Rice University biochemists are developing a system of "evolutionary forecasting" to better understand the mechanisms of antibiotic resistance.
"Our goal is to show antibiotic makers which sets of genes a pathogen will modify to become drug-resistant," said Yousif Shamoo, the principal investigator on a new $1 million grant from the National Institute of Allergy and Infectious Diseases. "If they know the molecular path that an organism will take to become resistant to a new drug, our hope is that they can find ways to cut off that path."
Drug resistance is a major and growing problem in the U.S. Despite the best efforts of the medical community, documented cases of antibiotic-resistant pathogens like methicillin-resisistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have increased dramatically in recent years. For example, a national study found that in 2004 more than 60 percent of patients in intensive care had MRSA and nearly 30 percent had VRE, compared with just 37 percent and 14 percent, respectively, in 1995.
Shamoo, associate professor of biochemistry and cell biology and director of Rice's Institute of Biosciences and Bioengineering, said the four-year study will follow two common pathogens, Escherichia coli and Enterococcus faecalis, as they adapt to front-line antibiotics. The researchers will identify the network of genetic adaptations that allow the pathogens to become increasingly drug-resistant.
"We'll start with a batch of bacteria in a controlled vessel, and on day one we'll add a small amount of the drug," Shamoo said. "Each day, we'll ramp up how much drug we add, and we'll do that continuously for weeks. The organism is forced to evolve or die. In previous studies using both drugs and using environmental changes like increased heat, we have found that organisms do evolve, and they do it in a repeatable, predictable way."
|Contact: Jade Boyd|