Degradation of polyurethane gastrostomy devices: what is the role of fungal colonization?

The aim of this study was to evaluate polyurethane percutaneous endoscopic gastrostomy (PEG) tube degradation and the role played by fungi. The inner surfaces of 20 used polyurethane tubes were brushed, and the brushing end was incubated for 7 days in Saburaud broth and cultured if fungal growth occurred. Three tubes used for 12 (sample 12w), 17 (sample 17w), and 96 (sample 96w) weeks and two new tubes were cut to produce several 4-cm-long equal halves. Six samples from the new tubes were considered control samples (Co sample), seven were incubated in Saburaud broth (Co sample + Sa.), and seven in the broth supplemented with Candida albicans (Co sample + Sa. + Ca). All samples underwent morphological examination by electron microscopy and differential scanning calorimetry measurements (DSC). All tubes had fungal colonization. DSC showed deterioration in all tubes including the new ones; adding Candida albicans had no additional effects. Morphological examination by electron microscopy showed a regular pattern in the Co sample, and thick biofilm, holes, and crevices in samples 12w, 17w, and 96w. The more the tubes had been used, the more severe were the changes. The Co sample + Sa and the Co sample + Sa + Ca showed no changes in the inner surface, but cryogenically fractured surfaces had holes and crevices. Yeasts constantly colonize PEG tubes and are likely to contribute to polyurethane deterioration. The impairment of new PEG tubes incubated in Saburaud broth suggests that other factors also play a role in polyurethane deterioration.