Steve joined Columbia University as a postdoctoral scholar, working in the laboratory of Samuel Danishefsky. Whilst living in New York he noticed that in wealthy neighbourhoods there were adverts for breastfeeding, whilst in poor neighbourhoods there were adverts for formula. He became interested in women's health disparities and the science of human breast milk. He started to investigate milk sugars (Human Milk Oligosaccharides, HMOs) and identified that they help infants fight disease.[2][3] HMOs are prebiotics and help to promote colonisation of the intestine with good bacteria.[4][5] Townsend was the first to show that HMOs prevent the formation of group B streptococcus and that they can even exert antimicrobial activity.[6][7] He was awarded the Ruth A. Lawrence Investigator Award for his work in human milk science.
Since Townsend's observation that oligosaccharides were crucial for antibacterial defence and to support infection-fighting proteins the oligosaccharide 2′-fucosyllactose has been included in a number of products.[8] Townsend went on to show that whilst 2′-fucosyllactose is in the breast milk of the majority of white women, black and Latina women do not necessarily produce the sugar. Townsend is investigating how the balance of HMOs impacts an infant's microbiome.[9]
Townsend was appointed an independent researcher at Vanderbilt University in 2014. He was awarded the Chancellor's Research Award in 2018 and made a Dean's Faculty Fellow in 2019.
^Craft, Kelly M.; Gaddy, Jennifer A.; Townsend, Steven D. (2018-08-02). "Human Milk Oligosaccharides (HMOs) Sensitize Group B Streptococcus to Clindamycin, Erythromycin, Gentamicin, and Minocycline on a Strain Specific Basis". ACS Chemical Biology. 13 (8): 2020–2026. doi:10.1021/acschembio.8b00661. ISSN1554-8929. PMID30071726. S2CID206528243.
