PREVENTING bacteria 鈥渢alking鈥� to one another can stop them becoming killers,
say microbiologists in Texas. The finding may lead to new approaches to fighting
infections鈥攁 welcome development as bacteria evolve resistance to
antibiotics.
Abdul Hamood and Kendra Rumbaugh of Texas Tech University in Lubbock and
colleagues studied Pseudomonas aeruginosa, which can infect wounds and
kill patients with severe burns. If anaesthetised mice with small scald wounds
are infected with P. aeruginosa, 95 per cent of them die within 48
hours. But when the team inoculated animals鈥� wounds with bacteria in which
communication genes had been knocked out, the mortality rate fell to 6 per cent.
The bacteria also failed to spread.
The genes involved produce enzymes that churn out molecules called
autoinducers. When enough bacteria are present, the concentration of
autoinducers passes a threshold level that causes the bacteria to switch on
virulence genes, allowing them to spread through the host.
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This allows bacteria to build a bridgehead before running riot, says Barbara
Iglewski of the University of Rochester, New York, who collaborated on the
project. In doing so, they may avoid attracting the attention of the immune
system.
Hamood hopes it will be possible to find drugs that block bacterial
communication. 鈥淭his approach does not kill cells, it blinds them,鈥� he says.
鈥淭here is no pressure for mutant bacteria to become resistant to treatment.鈥�