Scanning electron microscopy of the internal wall topography of enteral feeding tubes.

A range of commercially available naso-gastric and naso-enteric tubes was examined by scanning electron microscopy (S.E.M.). Surface irregularities in which micro-organisms could become trapped were observed on the internal walls of all the samples. Fine bore tubes which had been perfused for 8 h with a milk based feed experimentally contaminated with Staphylococcus aureus showed patches of residual feed and S. aureus cells on their interior surfaces. The potential hazards of entrapment and/or attachment of micro-organisms to the interior walls of these tubes are discussed.