LegenDAIRY Pink Breast Milk: A Case of Serratia Marcescens Colonization

Serratia marcescens is a rare colonizer of breast milk in the community setting, and sufficient bacterial burden to manifest clinical disease is even more uncommon; however, neonatal outcomes from S. marcescens infections in the inpatient setting can be devastating to include sepsis and neonatal demise. Given this risk and the paucity of case reports, recommendations range from expectant management to prophylactic antibiotics and cessation of breastfeeding. Here we present a literature review and a case of S. marcescens colonization obscured by symptoms in both the patient and her infant. A 30-year-old G8P4135 who was exclusively breastfeeding her 2-month-old infant contacted the Women's Health Clinic via her electronic medical record portal with a concern for contaminated breast milk after the milk left in a bottle overnight turned bright pink. Milk cultures from bilateral nipples showed colonization with S. marcescens. Following a literature review, decision was made to encourage continued breastfeeding and forego prophylactic antibiotics. She subsequently developed a febrile upper respiratory illness, and workup was negative for bacteremia with S. marcescens. Her colonization ultimately resolved spontaneously, and she continued breastfeeding without complication.Precis: Serratia marcescens is an uncommon colonizer of breast milk that does not require prophylactic antibiotics or cessation of breastfeeding in most cases. Precis: Serratia marcescens is an uncommon colonizer of breast milk that does not require prophylactic antibiotics or cessation of breastfeeding in most cases.