Differences in the growth of microorganisms depends on the type of semi-solid enteral nutritional supplements

BACKGROUND: Enteral nutritional supplements are used in many medical facilities and home care, but require appropriate management because they are nutrient-rich products. Recently, infection control methods for Ready To Hang (RTH) preparations, which are widely used and are expected to reduce the risk of infection, have not been established in Japan and are dependent on caregivers. Therefore, we evaluated the difference in the growth of microorganisms depending on the type of enteral nutrients following contamination with microorganisms. METHODS: Nine types of enteral nutrition were used. Escherichia coli (E. coli) W3110, Serratia marcescens (S. marcescens) NBRC3046, and Candida albicans (C. albicans) IFM61197 were used as test bacteria. The bacterial solution was added to the enteral nutritional supplement, adjusted, and the number of bacteria was measured at 0, 4, 8, and 24 h after the addition of the bacterial solution at 25 °C and in the dark. RESULTS: E. coli and S. marcescens grew in RACOL(®)-NF SemiSolid for Enteral Use, Hine(®) Jerry AQUA, and Mermed Plus(®) over a 24-h period; however, a decrease was observed for other enteral nutrition products. In contrast, C. albicans grew in all enteral nutrition products. CONCLUSION: Because the viscosity and calorie content vary among enteral nutrition preparations in which growth was observed, we found that pH had the greatest effect on the differences in bacterial growth. Nonetheless, C. albicans growth occurred in all nine types of enteral nutrients, indicating that unlike bacteria, its growth was independent of pH. If semi-solid enteral nutrients are contaminated with microorganisms for any reason, microorganisms will grow, so appropriate infection control is necessary to prevent infection.