Time course changes in bacterial contamination with the new standard enteral feeding connecter (ISO 80369-3)

Abstract

Objective: The enteral feeding connecter that meets the Japanese standard has started being replaced with a connecter that meets the international standard ISO80369-3 from December 2019 in Japan. We prepared a feeding apparatus using the Japanese standard connecter or ISO standard connecter, with and without use of an adapter, to compare microbial contamination under experimental conditions.

Methods: An enteral formula was injected into the feeding apparatus twice a day for 14 days. Purified water used for flushing was recovered and cultured. The number of bacterial colonies was counted and bacterial strains were identified. Also, three conditions (no flushing, flushing with water, and replacing the connecter) were evaluated when the two different connecters were used with an adapter.

Results: Bacterial counts exceeded 104 CFU/mL on day 9 regardless of whether the Japanese or ISO standard connecter was used, as well as on day 7 if the two connectors were both used with an adapter. Bacteria identified were those associated with diarrhea or sepsis. The bacteria identified after using the adapter were similar to those identified from the feeding tube. There were no differences between the three maintenance conditions when using the adapter.

Discussion: The risk of adverse events caused by microbes is likely to increase on day 9 and beyond regardless of the standard connecter used, suggesting microbial contamination will not be altered by replacing the Japanese standard connecter with the ISO one. It is necessary to pay sufficient attention to bacterial contamination when an adapter is used, and mixed use of the different standard connecters should be avoided as much as possible.