Scripps research team blocks bacterial communication system to prevent deadly staph ...( LA JOLLA CALIFORNIA OCT. 30 2007 -- ...)

LA JOLLA, CALIFORNIA, OCT. 30, 2007 -- In hopes of combating the growing scourge of antibiotic-resistant bacteria, in particular drug-resistant staph bacteria, a team of scientists from the Scripps Research Institute has designed a new type of vaccine that could one day be used in humans to block the onset of infection. The advantage of the new vaccine is that it would work not only on current bacterial resistant stains but also would not induce the potential for new bacterial resistance because, rather than killing bacterial cells, it blocks their communication system, preventing the shift from harmless to virulent, thus allowing the bodys natural defenses to combat the bacteria.

The work was published in the October 29 issue of the journal Chemistry and Biology.

Staph and other infections are becoming increasingly deadly because many strains of the bacteria that cause disease develop resistance to the array of antibiotics used to control them. A Centers for Disease Control (CDC) report released last week estimated that more than 94,000 Americans were infected in 1995 by a drug-resistant staph superbug called methicillin-resistant Staphylococcus aureus (MRSA), and more than 18,000 Americans died that year during hospital stays involving this type of infection.

The bacterial infection process is dependent on a sort of chemical conversation between individual bacterial cells, referred to as quorum sensing. In their free-living state, bacteria are typically easy to kill and non-virulent. The shift to virulence is dependent on small molecules emitted by bacteria known as autoinducers, because bacteria sense when concentrations of these autoinducers are high enough to suggest a large number of other bacteria are present.

Bacteria basically sense they have enough of their buddies around to allow them to say, 'OK, we're in a favorable environment to start turning on certain genes,' says team leader Professor Kim Janda, director o
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