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Breast milk is considered the ideal and preferred feeding for all infants through the first 4-6 months of life. It provides many short and long-term benefits to the infant and mother. In the absence of breastfeeding, expressed breast milk is the best way to provide nutrition. In the United States, the majority of breastfeeding mothers express milk at some point during the course of lactation. Breast milk is a dynamic fluid and its content changes with duration of lactation and varies between and among women. Many factors such as maternal diet and medications affect the constituents of breast milk. In addition, method of breast milk expression, handling, and storage can also influence its contents.

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Introduction: In addition to hand washing and wearing masks, social distancing and reducing exposure time to <15 minutes are the most effective measures against the spread of COVID-19. Unfortunately, three of these guidelines are very difficult, if not impossible, for nursing babies: they cannot wear masks, stay six feet away from the lactating breasts, nor consistently finish within 15 minutes while nursing. We report a case of a nursing mother with SARS-CoV-2 infection, documenting changes of immune cells and cytokines in breast milk with and without the infection. Case Description: With Institutional Review Board (IRB) approval, we obtained expressed breast milk samples from a lactating mother before and during SARS-CoV-2 infection as documented by reverse transcription-PCR. Using flow cytometry analysis, we measured the immune cell profiles and expression of cytokines such as interferon alpha (IFNa) in milk leukocytes before and during infection. Results: There was an eightfold increase in IFNa+ milk leukocytes, from 1% before SARS-CoV-2 infection to 8% when actively infected. The milk macrophages showed the highest increase in IFNa expression. Both T and B lymphocytes showed mild increase. Innate lymphoid cells, neutrophils, and natural killer cells showed no increase in IFNa expression and the dendritic cells actually showed a reduction. Conclusion:We document the presence and high expression of IFNa in the breast milk macrophages of a lactating mother with confirmed COVID-19, compared with her milk before the infection.

Pseudaminic acid and its biosynthetic altropyranoside precursors are bacterial components currently being investigated toward novel antibacterial strategies. One structural feature associated with these naturally occurring flagellar carbohydrates is the different N-acylation patterns on the two amido functionalities, posing a synthetic challenge. A new one-pot methodology is reported and a scope of diverse N2/N4-differentiated analogs are presented via a Staudinger reduction-mediated regiospecific O3 → N4 acyl migration, followed by an autonomous N2-acylation.