Neon Pink Breast Milk Stain in the NICU

Pink discoloration in breast milk is a rare phenomenon arising from various benign or pathological causes. Serratia marcescens, a gram-negative bacterium known for its characteristic red pigment prodigiosin, is a notable cause. This case report examines the clinical approach, diagnostic workup, microbiological findings, and management strategies for a neonate presenting with neon pink stains in breast milk. A female neonate born at 30+5 weeks gestation via repeat cesarean section was admitted to the neonatal intensive care unit (NICU). On day of life (DOL) 28, bright pink staining was observed in expressed breast milk (EBM) and secretions. Initial management included a septic workup, temporary cessation of feeds, and cultures of breast milk and fortified breast milk. The infant was started on piperacillin-tazobactam empirically while awaiting culture results. Blood cultures were negative, but cultures of breast milk and tubing showed heavy growth of S<i>erratia marcescens</i>, <i>Klebsiella oxytoca</i>, and <i>Pseudomonas</i> species. Feeds were resumed with Similac Special Care 24 kcal/oz, and the mother was treated with ciprofloxacin for seven days. Repeat cultures of breast milk showed no gram-negative bacterial growth. <i>S. marcescens</i>, an opportunistic pathogen, can cause pink discoloration in breast milk due to its pigment prodigiosin. The bacterium is associated with hospital-acquired infections, particularly in NICUs, where it thrives in moist environments and can contaminate breast pump equipment and feeding utensils. Rigorous infection control measures, including proper sterilization and handling of breast milk, are essential in preventing outbreaks. This case highlights the importance of thorough investigation and prompt management of unusual findings such as pink breast milk. Adhering to stringent hygiene and infection control protocols is critical in ensuring the safety of neonates and the breastfeeding process.