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Release: May 21, 1999

UI researcher outlines need for bacterial biofilm research

IOWA CITY, Iowa -- Physicians routinely prescribe antibiotics to treat bacterial infections; however, such treatment is generally ineffective if bacteria cluster in colonies called biofilms. Now that researchers are beginning to understand biofilms, the scientific community must focus attention on developing therapeutic agents to combat biofilm infections, a University of Iowa researcher wrote in the cover story for the May 21 issue of Science.

"It has become more and more clear that we need to begin to think of bacteria in groups working together," said E. Peter Greenberg, Ph.D., UI professor of microbiology and co-author of the Science article. "This article is really an announcement to the scientific community. It's time to think about and attack the medical biofilm problem."

Biofilms are organized groups of bacteria that work together to defend against attack from antibiotics and the body's immune system. Biofilms can grow from a bacterium that attaches to a surface, such as a cell lining a blood vessel. The bacterium may then begin to multiply and spread across the surface. When the cells reach a certain density, they build a complex biofilm structure.

A number of infections involve biofilms, from common problems such as dental caries and infections caused by contact lenses, medical devices and sutures to infections associated with cystic fibrosis. Antibiotics often provide some relief from symptoms but fail to cure the basic ongoing infection, Greenberg said.

The Science article by Greenberg and his colleagues at Montana State University comes in the wake of the National Institutes of Health announcement to make biofilm research a priority.

While scientists have been tackling bacterial infections for more than a half century, it wasn't until the past decade or so that the scientific community began to appreciate that bacteria organize themselves in elaborate ways, such as biofilms.

"It has been like an embarrassment swept under the rug that nobody wants to deal with because it's harder to attack the problem if you have to worry about things working in groups," Greenberg said.

Any battle plan against biofilm infections will need to involve strategies for compromising the bacteria's sense of community, Greenberg said.

"If we can target the community's signaling-based agents, we might be able to prevent the formation, or promote the detachment, of the biofilm," he said.

Greenberg and his colleagues are using this strategy against Pseudomonas aeruginosa, which cause chronic and serious lung infections in people with cystic fibrosis. Last year the researchers discovered a signal molecule essential for that biofilm's development.

"New clues about biofilm formation increase our understanding of pseudomonas and offer tremendous insights toward therapies," said Robert J. Beall, Ph.D., president and chief executive officer of the Cystic Fibrosis Foundation. "This type of infection represents the chief cause of morbidity and mortality for all those battling cystic fibrosis; therefore, we hope to quickly convert promising insights into innovative new treatments."

The UI team is now working to determine if this finding for Pseudomonas aeruginosa can be generalized to other bacteria and, if so, how the information might be used to dislodge or impair the biofilms. This information might then enable researchers to find ways to produce more effective antibiotics or novel therapeutic approaches to fight bacterial infections.

Work in the authors' laboratories is supported by the Cystic Fibrosis Foundation, the National Institutes of Health and the National Science Foundation.