Meeting News Coverage

Colonization with S. aureus declines with age as gram-negative pathogens increase

WASHINGTON — 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 Pedro Alvarez-Fernandez, MD, a research fellow in Pediatrics/Infectious Disease at the University of Texas Medical Branch, Galveston, Texas, who presented his study findings here during the Pediatric Academic Societies Annual Meeting.


Pedro Alvarez-Fernandez

Alavarez and colleagues studied the rate of S. aureus colonization at monthly intervals and during viral upper respiratory infection (URI) in the first 6 months of life. Methicillin-resistant S. aureus (MRSA) has lower ability to maintain prolonged colonization than methicillin-susceptible (MSSA) strains in the first 6 months of life. Colonization in this age group is not associated with the risk for invasive infection.

“We are surprised by the reduced ability of MRSA strains to maintain prolonged colonization as compared to MSSA strains. This needs further study. We also wonder why the colonization rate declines quickly over few months. Is it the immune factors or the changes in the nasopharyngeal microbiom that that protect against S. aureus colonization?” Alvarez told Infectious Diseases in Children. “We found that as the colonization with Gram-negative bacteria that cause otitis media goes up S. aureus colonization declines.”

The investigators also studied the association of S. aureus colonization with environmental and host factors.

For more information:

Alvarez-Fernandez P. #1533.452. Presented at: Pediatric Academic Societies Annual Meeting; May 4-7, 2013; Washington.

Disclosure: Alvarez reports no relevant financial disclosures.

See more from Pediatric Academic Societies Annual Meeting