Scientists and clinicians have known for many years that gold-colored strains of a bacterium called Staphylococcus aureus tend to be cause more disease than colorless strains. The color of these bugs comes from anti-oxidant molecules called carotenoids. Similar molecules also give carrots their color and are often touted for their ability to boost the immune system.

Nizet and colleagues now show that these pigmented molecules help S. aureus defuse damaging molecules that are produced by neutrophils in order to kill the bacteria. When the researchers removed the carotenoids from the bacteria, they became more vulnerable to immune attack. Nizet suggests that drugs that inhibit carotenoid synthesis might be useful for treating S. aureus infections, which can quickly develop resistance to traditional antibiotics.

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Contact: Nickey Henry
henryn@rockefeller.edu
212-327-8366
Journal of Experimental Medicine
11-Jul-2005