Selenium Bandages and Cotton Cloth That Kill Microorganisms in Wounds.

INTRODUCTION: The material of a bandage plays an important role in wound management. Microorganisms can colonize the dressing and release toxins, which create dead cells in the wound. This allows the microorganisms to bind the dead cells and infect the wound. Thus, a dressing is needed that kills bacteria in the bandage. To combat health care-associated infections, antimicrobial treatment of medical textiles, such as gauze, uniforms, curtains, bed sheets, gowns, and masks, is required. Besides, antimicrobial resistance is another major problem of this century. Antibacterial overuse has contributed to drug-resistant bacteria. To combat these two problems, we synthesized new organo-selenium compounds that can be attached to the cotton of the dressing. We then used an in vivo wound model, which allowed us to measure the effectiveness of selenium attached to a cotton dressing, to prevent bacteria from infecting a wound. MATERIALS AND METHODS: Organo-selenium was attached to cotton fabric, resulting in a fabric with 0.1% selenium covalently attached to it. Staphylococcus aureus (as well as methicillin-resistant S. aureus [MRSA]), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Wounds were made on the backs of mice. The material was used as a bandage over the wound. Bacteria were injected into the wound under the bandage. The amount of bacteria in the wound after 5 days was determined. A similar study was performed using dressing material that was soaked in phosphate buffered saline at 37 °C for 3 months before use. RESULTS: Cotton dressing with selenium attached showed complete inhibition (7 logs, as compared with control dressing) of different bacterial strains, in both the dressing and "the tissue" of the wound. Similar results were obtained using selenium cotton dressing that was soaked for 3 months before use. Control cotton with no selenium showed complete infiltration of bacteria into the wound and the dressing. In addition, a study was performed under Food and Drug Administration standard methods to show the ability of the selenium to kill bacteria in the fabric, using material that was washed 5 times in detergent. This also showed complete killing of bacteria in the fabric. CONCLUSIONS: The results show that the selenium remains in the dressing after washing and is able to completely protect the wound from bacterial infection. In the selenium bandage, no bacteria were found in the bandage or the wound after 5 days.

Minocycline and Diacetyl Minocycline Eye Drops Reduce Ocular Neovascularization in Mice.

Purpose: To evaluate the efficacy of minocycline and a novel, modified minocycline analogue that lacks antimicrobial action, diacetyl minocycline (DAM), on choroidal neovascularization (CNV) in mice of both sexes. Methods: CNV was induced via laser injury in female and male C57BL/6J mice. Minocycline, DAM, or saline was administered via topical eye drops twice a day for 2 weeks starting the day after laser injury. CNV volume was measured using immunohistochemistry labeling and confocal microscopy. Results: Minocycline reduced lesion volume by 79% (P ≤ 0.0004) in female and male mice. DAM reduced lesion volume by 73% (P ≤ 0.001) in female and male mice. There was no significant difference in lesion volume between minocycline and DAM treatment groups or between female and male mice. Conclusions: Both minocycline and DAM eye drops significantly reduced laser-induced CNV lesion volume in female and male mice. While oral tetracyclines have been shown to mitigate pathologic neovascularization in both preclinical studies and clinical trials, the present data are the first to suggest that tetracycline derivatives may be effective to reduce pathologic CNV when administered via topical eye drops. However, the action is unrelated to antimicrobial action. Targeted delivery of these medications via eye drops may reduce the potential for systemic side effects. Translational Relevance: Topical administration of minocycline and/or DAM via eye drops may represent a novel therapeutic strategy for disorders involving pathologic CNV.

Organoselenium coating on cellulose inhibits the formation of biofilms by Pseudomonas aeruginosa and Staphylococcus aureus.

Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.