UW News

October 8, 2004

Distinguished molecular microbiologist to chair department at UW School of Medicine

Dr. E. Peter Greenberg, a pioneer in the study of bacterial cell-to-cell signaling, which is required for a number of bacteria to cause diseases and is important in the development of several chronic infections in humans, has been selected to chair the University of Washington School of Medicine’s Department of Microbiology. Greenberg’s appointment, as announced by Dr. Paul G. Ramsey, vice president of medical affairs and dean of the School of Medicine, will be effective Jan. 1, 2005.

Greenberg’s work has led to new approaches to tame bacteria like those that persist in the lungs of people with the deadly genetic disease cystic fibrosis.

For years, scientists have taught that the great danger of bacteria is that they multiply rapidly and in an infection can overcome the host by shear numbers. Greenberg co-authored a cover story in the journal Science in 1999 that reported that dangerous bacteria work cooperatively in groups — communities comparable to ant hills or human cities — and bacteria will have to be analyzed and eventually combated as groups, not as individual bacteria.

Greenberg’s research interests include the study of the bacterium Pseudomonas aeruginosa. Pseudomonas can cause infections in people with compromised immune systems, those with cystic fibrosis, burn victims and others. Pseudomonas infections are often difficult to cure. There are relatively few antibiotics that are effective. In some cases — such as infections in the lungs of people with cystic fibrosis — Pseudomonas form a biofilm community that is shielded and even the most effective antibiotics cannot clear these biofilm infections entirely. At best, the antibiotics can help manage these chronic infections.

The UW already has a variety of active cystic fibrosis and Pseudomonas programs on both the basic science and clinical levels. UW researchers co-authored a study of the Pseudomonas genome in 1999; Greenberg’s group then analyzed the genes to determine which were most likely to explain the bacteria’s biofilm virulence.

“Dr. Greenberg will add his expertise to an already distinguished Department of Microbiology, and will find immediate research partnerships with our pioneering Department of Genome Sciences, our faculty in infectious diseases and immunology, and faculty in many other fields of study,” Ramsey said.

Greenberg was recently elected to the National Academy of Sciences and is a fellow of the American Academy of Arts and Sciences. He presently holds the Shepperd Endowed Professorship in molecular pathogenesis in the Department of Microbiology at the College of Medicine, the University of Iowa. Greenberg has a B.A. in biology from Western Washington University, an M.S. in microbiology from the University of Iowa and a Ph.D. in microbiology from the University of Massachusetts. He was on the faculty of Cornell University before moving to Iowa in 1988, and has published more than 115 papers in scientific journals.

“Dr. Greenberg has made invaluable contributions to the field of CF science over the years and we are pleased that he will continue to do so in his new role at the University of Washington,” said Dr. Robert J. Beall, president and CEO of the Cystic Fibrosis Foundation. “Unlocking the secrets and complexities of Pseudomonas could have a tremendous impact on the development of future CF therapies. We look forward to even greater collaboration with Dr. Greenberg and the University of Washington going forward.”

Through his research, Greenberg has found that Pseudomonas cells communicate with each other to coordinate their activities as a group and this is important in the biofilm infections of cystic fibrosis lungs. This bacterial communication phenomenon is known as “quorum sensing,” a term coined by Dr. Greenberg and his co-workers, which allows bacterial cells to understand if there is a quorum ­ a sufficient number of cells to begin the production of factors that damage the host body. In a sense, bacteria spread like human homes in a suburb, and like a suburb, the community is capable of cooperation and accomplishing more than the sum of its parts.

“My research has helped to determine that bacteria are much more sophisticated than people used to think. Researchers are going to have to create more sophisticated, interdisciplinary approaches than everyone originally thought if we want to understand bacterial groups. The UW School of Medicine has already shown its dedication to innovation by forming the unique Department of Genome Sciences, which combines several disciplines. I look forward to working with my fellow faculty in microbiology, as well as other UW faculty, in the long path to using biological understanding to protect human health,” Greenberg said.

Greenberg also is trying to determine what genes in Pseudomonas in particular allow it to fight off the antibiotics that kill so many other bacteria. That is no small task, as the UW researchers found in 1999 that Pseudomonas has a large genome. Of nearly 6,000 genes, about 40 may be involved in allowing Pseudomonas biofilms to resist antibiotics, according to Greenberg’s research. Pseudomonas eventually leads to death in people with cystic fibrosis, and also causes problems for people with compromised immune systems.

Besides the work of researchers studying Pseudomonas, the UW has several other programs for studying and treating cystic fibrosis. For example, faculty based at Children’s Hospital and Regional Medical Center in Seattle have helped to develop and study innovative treatments for the disease. The nucleus of their work is the CF Foundation’s Therapeutics Development Network (TDN), for which Seattle is the coordinating center. The TDN is a collaboration of 18 CF clinical research institutions throughout the United States that is funded by Cystic Fibrosis Foundation Therapeutics (CFFT) and the National Center for Research Resources.


For more about the pseudomonas genome:

For more about cystic fibrosis research at UW and Children’s Hospital and Regional Medical Center: http://www.washington.edu/research/pathbreakers/1993a.html

For more about Dr. Greenberg’s work: