My research combines field-based sample collection, laboratory analyses, and bioinformatics to explore environmental influences on the microbiome. I am particularly interested in the influence of social environments on infant microbiome development and associated health outcomes, as these dynamics are relevant to questions about human evolution as well as contemporary issues in global health.
Global variation in the human milk microbiome
I am working with collaborators in the International Milk Composition Consortium to characterize the human milk microbiome across populations living in Tanzania, Burkina Faso, and Pakistan. Ongoing work explores global variation in milk microbial profiles, as well as associations to infant growth and health.
Social environments and the infant skin and gut microbiomes in Chicago, USA
Working with physicians and families, we explored the relationship between infants’ social environments and the diversity of their skin and gut microbiomes.
We found that bacterial diversity varied across infant body sites, and that certain infant-caregiver interactions (e.g. feeding) had stronger associations to infant bacterial diversity than others (e.g. playing).
Household environments and the infant gut microbiome in Cebu, Philippines
In collaboration with colleagues at the Office of Population Studies at the University of San Carlos in Cebu, we found that prenatal household size was a strong predictor of infant gut microbial diversity. However, the association between household size and the gut microbiome differed at 2 weeks and 6 months of age.
As infants grow older and become more mobile, they may interact with microbes that persist in the broader household environment.
Infant skin microbiome across populations in Veracruz, Mexico and Chicago, USA
We conducted a comparative study of the infant microbiome in Mexico and the USA. In collaboration with Dr. Alejandra Núñez de la Mora of Universidad Veracruzana, we found that variation in infant skin microbial communities is driven by (a) body site and (b) lifestyle factors that shape infants’ physical and social environments.
We also tested different sample collection and storage methods, and found that storing samples in ethanol is a promising, field-friendly approach for conducting skin microbiome research in resource-limited settings.
Characterizing the human and cattle skin microbiome in Mandena, Madagascar
We found that the degree of similarity between skin microbial communities of agriculturalists and their livestock varies across different human body sites, and that antibacterial soap use impacts the composition of skin microbial communities in unequal ways across different body sites. Our research supports the idea that different body sites harbor distinct ecological niches for microbes, and that contact with the environment shapes microbial communities across the skin.
Global health research in Mandena, Madagascar
In collaboration with the Duke Lemur Center’s SAVA Conservation program, additional research in this community focused on elevated rates of hypertension, and in a study led by Dr. David Samson, patterns of sleep ecology.
You can view a full list of my publications here.
Melissa B. Manus, PhD, MSc 