A team of microbiologists has found a chink in the armor of an opportunistic microbe that is a top cause of infections in hospitals. By genetically altering the bacteria Pseudomonas aeruginosa, the team was able to break up the colonies that normally make the germ resistant to detergents and antibiotics. The work relies on mucking up the chemical communication system that the bacteria use to "talk" to each other when releasing toxins and gaining a foothold in humans, animals, and even plants.
The work, by scientists at Montana State University, the University of Iowa, and the University of Rochester, is reported in the April 10 issue of Science.
Pseudomonas is a very common bacteria on our food, in dirt, and throughout our houses. The tiny rod-shaped germ targets people whose defenses are already weakened: burn victims, people who have had surgery, cancer patients on chemotherapy, or patients on ventilators or with IV tubes or catheters. Altogether it's the single most common cause of infections acquired by patients during their stay in the hospital. The bacteria are also a big killer of patients with cystic fibrosis: Nearly all children with the disease are infected by Pseudomonas, which makes patients' lung mucus much thicker and compounds their breathing problems.
More so than many bacteria, Pseudomonas can be extraordinarily resistant to antibiotics, largely because the bacteria form themselves into sticky clusters called biofilms. A biofilm is like a slime home base where billions of bacteria stick together, becoming hundreds of times more resistant to detergents and antibiotics than when they're circulating alone.
"Bacteria love to stick, and once they settle down and make
a biofilm, it's notoriously difficult to get rid of them," says
Barbara Iglewski, professor of microbiology and immunology at
Rochester and one of the authors. "We'll take a culture from a
patient and send it to a clinical lab, and the lab will sa
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Contact: Tom Rickey
trickey@admin.rochester.edu
716-275-7954
University of Rochester
10-Apr-1998