As an infant’s nasopharynx is colonized with gram-negative pathogens, the colonization with Staphylococcus aureus declines. S. aureus colonization of infants begins early in life and declines quickly, according to Dr. Pedro Alvarez-Fernandez, a research fellow in pediatrics/infectious disease at UTMB, who presented his study findings here during the Pediatric Academic Societies Annual Meeting.