Investigation of environmental bacterial contamination associated with distilled water in a neonatal formula preparation unit.

BACKGROUND

Environmental microorganisms detected in neonatal feeding preparation areas may raise concern for healthcare-associated outbreaks and warrant investigation to identify potential environmental sources of contamination.

METHODS

Between July 2025 and February 2026, repeated bacterial growth was detected during routine microbiological surveillance of formula prepared for neonates. An investigation was conducted, including sampling of powdered formula, prepared formula, and distilled water. Bacterial identification was performed using routine methods, and genetic relatedness among selected Herbaspirillum isolates was evaluated using arbitrarily primed polymerase chain reaction.

RESULTS

Environmental microorganisms were isolated from prepared formula and distilled water, while powdered formula showed no growth. Repeated isolation of Herbaspirillum species demonstrated clonal relatedness, suggesting a common environmental source. No clinical infections associated with these microorganisms were identified among neonates during the study period.

CONCLUSIONS

This study identified environmental bacterial contamination associated with distilled water used during formula preparation. Molecular typing was valuable in confirming a common environmental source and guiding corrective interventions. Monitoring water sources is critical in neonatal care.