Efeito da lavagem de próteses vasculares sintéticas de politetrafluoretileno expandido (PTFEe) sobre a colonização bacteriana – um estudo in vitro

Abstract

Synthetic vascular grafts have provided life preservation and limb salvage for millions of patients worldwide. One of the most frequent causes of failure of these grafts is bacterial infection. Objective: To evaluate whether washing with different pre and post contamination solutions of expanded polytetrafluoroethylene (ePTFE) synthetic vascular prosthesis decreases bacterial colonization. Material and methods: For this study, the following microorganisms were evaluated: Staphylococcus aureus and Staphylococcus epidermidis, the suspensions with the microorganisms were adjusted to the turbidity corresponding to McFarland scale tube 0.5 (1.5 x 108 colony forming units). Thirty-six 1 cm-long fragments of the ePTFE vascular prosthesis were divided into three groups: prostheses contaminated by bacteria and not treated; prostheses contaminated by bacteria and treated before contamination; and prostheses contaminated by bacteria and treated after contamination. Treatments were performed with 0.5% chlorhexidine, antibiotic solution (1.0g cefazolin and 80mg gentamicin), lidocaine solution (20ml 2.0% lidocaine diluted in 500ml serum 0.9%) and pure lidocaine 2.0%. Incubation was 7 days. The prostheses were sown in culture medium and the area with colony formation was evaluated by fractal dimension. Results: In prewash, there was no growth of S. epidermidis with antibiotic solution and there was a 60% reduction in growth of S. aureus. In the wash after contamination, there was no growth of any bacteria with the antibiotic solution, there was no growth of S. aureus with pure lidocaine and there was a decrease in chlorhexidine colonization density of 53.34% in the wash before contamination and decrease 65.12% in the wash after contamination for S. aureus. There was a reduction of 58.14% for S. aureus with lidocaine solution in the wash after in vitro contamination of ePTFE prostheses. Conclusion: Washing before and after contamination with antibiotic solution was effective to decrease bacterial colonization by S. aureus and S. epidermidis in ePTFE prostheses in vitro. Washing before and after chlorhexidine contamination proved to be effective in decreasing bacterial colonization by S. aureus. Washing with pure lidocaine and lidocaine solution proved to be effective in decreasing bacterial colonization by S. aureus in the post-contamination wash.