The skin microbiome — the collection of microorganisms that live on the surface of the human body — plays a critical role in regulating the immune system, yet little is known about how infants first acquire skin microbes in early life. Since microbes are transmitted between people, and human infancy is highly social, interactions with caregivers may be a critical component of infant skin microbiome development. This doctoral dissertation project examines how infant social networks and specific interactions between infants and their caregivers influence the diversity of microbes living on infants’ skin. Results of this project shed light on the understudied relationship between social behaviors and the infant skin microbiome, as well as laying the foundation for future studies that connect early life microbial exposures to particular physiological outcomes. Study participants, including mothers and other caregivers, will receive personalized reports based on research results, including information about their social networks as well as the structure of their skin microbiome and how it compares to that of their infant. This project also contributes to enhancing diversity and inclusion by training undergraduate students from groups underrepresented in STEM research in skin microbiome laboratory methods and statistical analyses. The project also has public health translational potential with respect to infant wellbeing.
Unlike other great apes, human mothers rely on additional caregivers, such as grandparents and older siblings, for long-term assistance with infant care. Common infant care practices, including holding and carrying, promote direct skin-to-skin contact between caregivers and infants, suggesting opportunities for skin microbes to be shared with infants. This project will investigate how social caregiving influences the infant skin microbiome, with an emphasis on the microbial similarity between the skin of infants and their caregivers. Researchers will collect skin swab samples from infants, mothers, and additional caregivers, and use microbial gene sequencing to characterize and compare the skin microbes present in the samples. Caregivers will complete questionnaires that ask about the frequency of specific practices that put them in physical contact with infants. The researchers will use these data to generate social networks that describe social relationships between infants and their caregivers, suggesting potential routes through which skin microbes are shared with infants. This project offers a novel perspective on the benefits of social caregiving to infants, and the results will highlight the role that the social environment plays in linking early life microbial exposures to health outcomes.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
