Best way to kill bacteria? Stop them talking - study
12:01 p.m. Apr 09, 1998 Eastern
By Mark Weinraub
WASHINGTON, April 8 (Reuters) - Bacteria that form deadly communities in the body use a chemical to communicate with one another and forge stronger, and sometimes near-invincible, bonds, scientists said on Thursday.
Pseudomonas aeruginosa bacteria cells use a chemical to ``talk'' to each other when forming strongholds in the body called biofilms, they wrote in a study published in the journal Science.
Interfering with the conversations between the cells may keep them from infecting an area or joining together to form biofilms, said Peter Greenberg, a University of Iowa microbiology professor who worked on the study.
Individually, pseudomonas aeruginosa cells can be controlled by antibiotics but when the bacteria form biofilms they are much harder to fight and can cause untreatable lethal infections.
``We're hoping that by understanding the signal ... we can mount a search looking for agents that block the signaling process,'' Greenberg said in a telephone interview.
More research is needed to determine if other kinds of bacteria communicate in the same way when forming biofilms, Greenberg said.
The study should also spark more research into the precise actions in bacteria cells that the chemical induces, said Richard Losick, a professor of molecular and cellular biology at Harvard University.
``This really opens the way to an exciting period,'' Losick said in a telephone interview. ``The thing will be to find out what sets of (bacteria) genes this (chemical) turns on.''
The finding advances the idea that bacteria are much more advanced and ``socialized'' organisms than previously thought. Scientists should search for more signs of communications between individual bacteria, Losick said.
Similar conversational behavior, called quorum sensing, is found in marine bacteria, Greenberg said. Marine bacteria take a census of themselves to find out how many other bacteria are present before deciding what to attach to.
Pseudomonas aeruginosa is a common bacterium that can be found on fruits, vegetables, the taps of sinks and in the soil.
It can form biofilms in people whose immune systems have been suppressed or damaged, Greenberg said. It commonly infects burn victims and the lungs of cystic fibrosis patients.
When bacteria form biofilms, they join in multicellular columns, often shaped like mushrooms on top of stalks with channels for waste disposal between the individual bacteria. The cell walls of the bacteria become tougher and more difficult to penetrate, Greenberg said.
Greenberg called for more lab tests on bacteria in biofilm state, which is how they are usually found in nature. Most tests are performed on individual bacteria cells.
Pseudomonas aeruginosa biofilms also often attach to medical devices implanted in the body such as heart valves. The bacteria can cause the devices to fail.
Catheters provide an entry way for the bacteria to invade the body. Infected catheters can cause urinary tract infections, which account for more than 40 percent of all hospital acquired infections, according to the Centers for Disease Control and Prevention (CDC). REUTERS
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