Adding bacteria to wounds could ward off dangerous infections
HOW do you prevent wounds becoming infected by dangerous superbugs? By first adding other bugs, say researchers in Canada who have found that a cousin of the yogurt bacterium can stop the growth of harmful bugs.
About 1 per cent of surgical incisions become infected. If the patient's immune system is weak, or the bacteria are antibiotic-resistant superbugs, such infections can kill.
Gregor Reid, a microbiologist at the University of Western Ontario, wondered if benign bacteria might help. So he and his colleague Jeffrey Howard coated several small sheets of silicone with Staphylococcus aureus, a major cause of hospital infections. Some were also coated with a strain of the harmless bacterium Lactobacillus fermentum called RC-14.
The researchers implanted the silicone sheets under the skin of rats. After a few days, incisions infected with S. aureus alone were swollen with pus. Those that received RC-14 as well were clean and healthy.
The RC-14 did not kill the S. aureus, but this could actually be good news. Bacteria become resistant to antibiotics when the non-resistant members of a colony all die. So they might take longer to develop resistance if growth is merely inhibited. "I think there is much less selective pressure with this type of strategy than with antibiotics," says Howard.
Howard has discovered that the active agent secreted by the RC-14 bacteria is a protein, which may prevent S. aureus from binding to human cells. In future, the protein could be applied directly to an incision, or used to coat surgical implants.
Using live bacteria is also an option, Reid says. "In patients facing death or amputation it is worthy of investigation."
Jonathan Knight reporting from the meeting of the American Society for Cell Biology in San Francisco.
New Scientist issue: 23/30 December 2000
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