Poster Presenter

A New Antibacterial Agent For Materials Functionalization: An Application On Polyamide Pd-Catheter Dressings
Isabel C. Gouveia, Daniela P. Sá, Mariana C. Henriques, José M. Fiadeiro, Ernesto Rocha and João A. Queiroz
Portugal

Background: In general, catheter associated infections are strongly involved with the adhesion of bacteria to device surface. They gain access to the catheter by migration externally from the skin along the exterior catheter surface into the exit site or internally on the catheter hub through its tip. This is more serious when the lifetime of catheter is long as in the case of peritoneal dialysis catheters (PDC).

The optimal care of peritoneal dialysis catheter exit sites is, however, not known. But there is consensus about the sterile application of a dressing onto a catheter to give out multiple purposes. The dressing provides a means of protection as well as prevention of catheter dislodgement caused by trauma. Most important, the dressing serves to help protect against the entry of microorganisms at the insertion/exit site, potentially causing a catheter-related peritonitis which can have serious impact on catheter loss, morbidity and mortality.

In the latest 10 years a few products concerning the abdominal catheter support were developed. However, none of them shows antibacterial activity.

The novelty of our proposal lays on the design of new polyamide (PA) catheter dressing functionalized with new antibacterial natural agents, to provide catheter support and help preventing bacterial contamination during catheter lifetime.

Development: Here, we report a new method involving thiolated natural compounds which provides an antibacterial effect onto dressings special designed for PDC and, more important, without any citotoxicity effect.

The biocidal mechanism is related with the higher content in R-S- groups. The sulfhydryl agents exert a profound bacteriostatic effect resulting in outgrowth inhibition. To evaluate the increase of these bioactive groups on the textile material, the estimation of sulfhydryl (R-S-) in solution was performed by the colorimetric Ellman / DTNB assay. Exhaustion was calculated by comparison to a standard curve of known concentrations of Cysteine. R-S- groups were also detected directly onto fibers by an adaptation to the DTNB assay. The antimicrobial activity was tested according to JIS 1902-2002 and ISO 27300 and the citotoxicity according to E DIN EN ISO 10993-5.

Results: It was found a MIC of 1% (over the weight of fiber) onto the functionalized gauze dressings. In the same conditions MLC was 6-8% owf both for Staphylococcus aureus and Klebsiella pneumoniae.
Our results firmly confirm the antibacterial effect of thiolated natural compounds onto polyamide based dressings, caused by the action of R-S- groups.

Conclusions: The new thiolated natural compounds are effective natural antibacterial agents with potential application on protective dressings specially designed for peritoneal catheters' protection.

It also lays a platform for the development of other antimicrobial related products