Comparative Efficacy of Silver- Containing Dressing Materials for Treating MRSA-Infected Wounds in Rats with Streptozotocin-Induced Diabetes

Objective. Silver plays an important part in severe wound man- agement, mainly by reducing microbial growth within dressed wounds and wound beds. However, it is unknown how silver-coated dressing materials affect diabetic wounds. The purpose of this study is to evaluate the efficacy of silver-containing dressing materials for the treatment of methicillin-re- sistant Staphylococcus aureus (MRSA)-infected wounds in streptozotocin- induced diabetic rats. Methods. Full-thickness skin defects were created on the backs of rats with streptozotocin (STZ)-induced diabetes (n = 108) and were infected with MRSA. The rats were assigned to 6 groups accord- ing to the wound dressing used: nanocrystalline silver (Acticoat, Smith & Nephew, Inc, London, UK), silver carboxymethylcellulose (Aquacel-Ag, ConvaTec, Skillman, NJ), silver sulfadiazine (Medifoam silver, Genewel Science Co Ltd, Seongnam, South Korea), nanocrystalline silver (Poly- Mem silver, Ferris Mfg Corp, Burr Ridge, IL), silver sulfadiazine (Ilvadon, Ildong Pharmaceuticals, Seoul, South Korea), and 10% povidone iodide (control). The wound size, histological findings, and bacterial colony count for each group was analyzed and compared to normal Sprague-Dawley rats. Results. Wound size decreased over time in every group. On day 10, a significant difference in wound area was detected between the silver dressing groups and the control group (P = 0.0040). In the wound biopsy, on days 4, 7, and 10, the would-healing effect increased in every group. However, between days 4 (P = 0.8250) and 10 (P = 0.9912), there was no statistical difference between groups. The number of bacteria in each group decreased with time in the bacterial wound culture. The silver dress- ing groups were more effective on antimicrobial efficacy, but there was no statistically significant difference between the silver dressing groups and the control group. Conclusion. Silver-containing dressing materials are an effective method for MRSA-infected wounds, but nano silver-containing dressing materials did not have better results in a diabetic rat model com- pared to a normal rat model in historical review. Further investigation is necessary to determine the relative safety of these products on the healing wound. Once that is done, the relative value of the products can be de- termined by balancing their antimicrobial and cytotoxicity characteristics.