In Vitro S. epidermidis and S. aureus Adherence to Composite and Lightweight Polypropylene Grafts

Background. Despite the significant risk of infection, prosthetic graft materials have become indispensable for incisional hernia repair. Composite and lightweight grafts have been developed to overcome adhesion and rigidity. The aim of this study was to evaluate in vitro S. epidermidis and S. aureus adherence to these new generation grafts, which have modified composition and textile properties. Materials and Methods. In this experimental study, sterile samples of multifilament polypropylene, multifilament lightweight composite, monofilament composite, and monofilament polypropylene grafts were incubated with slime positive S. epidermidis and S. aureus strains for 24 h. The grafts were washed and vortexed in saline. The saline was passaged to blood agar and incubated for 24 h. The colonies were counted. Naive and incubated graft materials were examined by scanning electron microscopy to reveal both textile properties and biofilm formation. Physicochemical properties were evaluated. Wilcoxon signed ranks test and Friedman test were used for statistical analysis. Results. S. epidermidis showed a significantly decreased adherence to monofilament polypropylene graft, and increased adherence to multifilament polypropylene graft (P<0.05). S. aureus showed a significant affinity for monofilament composite graft (P<0.05). SEM studies showed that biofilm formation was present on multifilament polypropylene graft. Conclusions. Both S. epidermidis and S. aureus had significantly less adherence to multifilament lightweight composite than multifilament polypropylene graft. S. epidermidis showed a greater affinity to monofilament composite graft compared with monofilament polypropylene graft. Overall S. epidermidis adherence for multifilament lightweight composite and monofilament composite was less than multifilament polypropylene and higher than monofilament polypropylene. S. epidermidis and S. aureus showed different adherence for each graft. Changes in material composition and textile properties may well influence bacterial adherence. (C) 2009 Elsevier Inc. All rights reserved.