The in vitro research of bacterial invasion of prosthetic vascular grafts: comparison of elastomer-sealed and gelatin-coated Dacron vascular grafts

PURPOSE: To investigate the process of bacterial invasion from the surface to inside prosthetic vascular grafts. METHODS: Elastomer-sealed Dacron vascular grafts (ESDVGs) and gelatin-coated Dacron vascular grafts (GCDVGs) were cut into 6-cm segments and placed in a U-shaped configuration on culture plates. Physiological saline was poured inside the grafts and a suspension of Pseudomonas aeruginosa was added to the outside. Samples taken from inside the grafts at nine time points for up to 60 h were spread on agar. Bacterial colonies were then analyzed. The grafts were also examined using scanning electron microscopy (SEM). RESULTS: Contaminated vascular graft models were produced in 18 ESDVGs (group T) and 12 GCDVGs (group G). The bacterial counts inside the vascular grafts in both groups increased over time. Bacterial colonies were confirmed in all samples from group G by 30 h, whereas bacteria appeared inside the grafts from group T at various times between 0 and 60 h. Bacteria were undetectable in one model from group T throughout the study. SEM revealed that the elastomeric membrane in the ESDVG was uneven. CONCLUSION: Bacterial invasion of vascular grafts does not always occur immediately after contamination. ESDVGs may be more resistant to bacterial invasion as they have a thicker and evenly enriched elastomeric membrane.