Experimental study on the use of a chlorhexidine-loaded carboxymethylcellulose gel as antibacterial coating for hernia repair meshes

Purpose Biomaterials with an antimicrobial coating could avoid mesh-associated infection following hernia repair. This study assesses the use of a chlorhexidine-loaded carboxymethylcellulose gel in a model of Staphylococcus aureus mesh infection. Methods A 1% carboxymethylcellulose gel containing 0.05% chlorhexidine was prepared and tested in vitro and in vivo. The in vitro tests were antibacterial activity ( S. aureus ; agar diffusion test) and gel cytotoxicity compared to aqueous 0.05% chlorhexidine (fibroblasts; alamarBlue). For the in vivo study, partial abdominal wall defects (5 × 2 cm) were created in New Zealand white rabbits ( n = 15) and inoculated with 0.25 mL of S. aureus (10 6 CFU/mL). Defects were repaired with a lightweight polypropylene mesh (Optilene) without coating ( n = 3) or coated with a carboxymethylcellulose gel ( n = 6) or chlorhexidine-loaded carboxymethylcellulose gel ( n = 6). Fourteen days after surgery, bacterial adhesion to the implant (sonication, immunohistochemistry), host tissue incorporation (light microscopy) and macrophage reaction (immunohistochemistry) were examined. Results Carboxymethylcellulose significantly reduced the toxicity of chlorhexidine ( p