The Pneumococcal Pilus Predicts the Absence of Staphylococcus aureus Co-Colonization in Pneumococcal Carriers

The determinants of the negative association between Streptococcus pneumoniae and Stapylococcus aureus colonization are unknown. In this matched case-control study, the odds of co-colonization with S. aureus were significantly lower for individuals carrying a piliated versus a nonpiliated S. pneumoniae strain, suggesting the pilus may be a determinant of the negative association.