One bug’s bane may be another’s break

From Chicago, at the Interscience Conference on Antimicrobial Agents and Chemotherapy

People who carry pneumococcus bacteria in their nasal passages may be partially protected against having their noses colonized by Staphylococcus aureus. The new finding could have important implications because a pneumococcus vaccine licensed in 2000 is reducing illnesses caused by that bacterium, also known as Streptococcus pneumoniae, while S. aureus is becoming increasingly resistant to antibiotics.

Both bacteria can live harmlessly in the nose, but either can cause serious illness if it spreads to other parts of the body. Gili Regev-Yochay of Sheba Medical Center in Ramat-Gan, Israel, and her colleagues checked the noses of about 1,500 people for the presence of the two bacteria. Hundreds of the volunteers tested positive for at least one of the pathogens.

After accounting for factors such as age, which influences the two pathogens differently, the researchers found that people who carry pneumococcus are only 47 percent as likely to harbor S. aureus as are those with pneumococcus-free noses. The finding suggests that pneumococcus inhibits S. aureus from colonizing the nose, Regev-Yochay says.

Israel hasn’t begun vaccinating against pneumococcus, but the United States has. “I wouldn’t stop vaccinating now,” says Regev-Yochay, but she suggests that researchers keep an eye on S. aureus as vaccinations increase.


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