The Influence of Maternal S. aureus anti-Hla neutralizing antibody on infant skin and soft tissue (SSTI) development in the first year of life

Staphylococcus aureus is the leading cause of infectious-related deaths. Vaccine development has been hampered by the recall of nonprotective immune responses from prior exposure, suggesting an effective vaccine may need to be given early in life. The goal of this pilot study was to correlate the maternal serologic response against S. aureus to an infant's risk for skin and soft tissue infection (SSTI) and colonization in the first year of life. Pregnant women were enrolled and maternal-infant dyads followed for 12 months. Maternal 3rd trimester and cord blood were obtained to determine the anti-S. aureus IgG and anti-α-toxin (Hla) neutralizing antibody (NAb) titers. Serial surveys and skin swabs were obtained from mothers at enrollment and from infants longitudinally to ascertain S. aureus colonization status and the incidence of SSTI. 63 pregnant women were enrolled, 54% with history of SSTI or asymptomatic S. aureus colonization at enrollment. Within 48-hours of delivery, 23% of infants had S. aureus colonization and 43% at 1-month. Maternal S. aureus colonization resulted in 7.4 increased odds of infant colonization at delivery. Higher cord blood anti-Hla Nab titer was associated with significantly lower risk for infant SSTI in the first year of life. S. aureus colonization occurs early in life, with over 40% of infants colonized by 1-month. These results are the first to demonstrate an association between higher transplacental anti-Hla NAb and protection against infant SSTI in the first year of life. Overall, these findings support Hla as a promising vaccine target.