Time-kill Kinetics of a Novel Antimicrobial Silver Wound Gel Against Select Wound Pathogens.

UNLABELLED: New treatments are needed as infection risk associated with diabetic, venous, and pressure ulcers are becoming more prevalent as comorbidities of obesity, aging, and major disease. Postsurgical, burn, and immunocompromised patients are also at an increased risk of wounds and infection. Silver has been utilized in treating various wounds associated with infections and, although highly effective, caution is required for use beyond 2 weeks due to potential silver cytotoxicity. To overcome this obstacle, an antimicrobial wound gel (CelaCare Technologies, Inc, Dallas, TX) was designed to allow low concentrations of a proprietary silver salt combined with acemannan, which has been demonstrated to aid wound healing. MATERIALS AND METHODS: This study's objective was to determine the time-kill kinetics of the antimicrobial wound gel vs 4 commercial topical silver products against 6 common wound pathogens and Bacillus subtilis as a spore-forming bacteria. RESULTS: The antimicrobial wound gel achieved a 2.9 log reduction in growth of Pseudomonas aeruginosa within 30 minutes, a 2.3 log reduction in Streptococcus pyogenes within 8 hours, a 2.1 log reduction in methicillin-resistant Staphylococcus aureus within 48 hours, a 2.3 log reduction in S. aureus within 24 hours, a 4.1 log reduction in Escherichia coli within 30 minutes, a 2.9 log reduction in B. subtilis within 60 minutes, and a 3.4 log reduction in Candida albicans within 90 minutes. Overall, the antimicrobial wound gel demonstrated broad antimicrobial coverage against all wound pathogens evaluated, and it was comparable to, or better than, other tested topical silver products containing substantially higher silver concentrations. CONCLUSION: The broad-spectrum antimicrobial activity of the wound gel indicates it could become a product alternative to current commercial products.

Chemical characterization of the immunomodulating polysaccharide of Aloe vera L.

The polysaccharide isolated by alcohol precipitation of Aloe vera mucilaginous gel was found to have a Man:Glc:Gal:GalA:Fuc:Ara:Xyl ratio of 120:9:6:3:2:2:1 with traces of Rha and GlcA. Linkage analysis of the endo-(1-->4)-beta-d-mannanase-treated sample yielded Manp-(1--> (approximately 26%), 4-Manp (approximately 53%), 2,4-Manp (approximately 3%), 3,4-Manp (approximately 1%), 4,6-Manp (approximately 1%), 4-Glcp (approximately 5%), 4-Xylp (approximately 1%), Xylp-(1--> (approximately 2%), Galp-(1--> (approximately 5%), and traces of 4,6-Galp and 3,6-Galp. Hydrolysis with strong acids produced a mixture of short oligosaccharides and an acid-resistant fraction containing greater relative fractions of Manp-(1-->, Araf-(1-->, Xylp-(1-->, and 4-Xylp than the bulk polysaccharide. NMR analysis of oligosaccharides generated by endo-(1-->4)-beta-D-mannanase and acid hydrolysis showed the presence of di-, tri-, and tetrasaccharides of 4-beta-Manp, beta-Glcp-(1-->4)-Man, beta-Glcp-(1-->4)-beta-Manp-(1-->4)-Man, and beta-Manp-(1-->4)-[alpha-Galp-(1-->6)]-Man, consistent with a backbone containing alternating -->4)-beta-Manp-(1--> and -->4)-beta-Glcp-(1--> residues in a approximately 15:1 ratio. Analysis of the sample treated sequentially with endo-(1-->4)-beta-d-mannanase and alpha-D-galactosidase showed that the majority of alpha-Galp-(1--> residues were linked to O-2, O-3, or O-6 of -->4)-beta-Manp-(1--> residues, with approximately 16 -->4)-beta-Manp-(1--> residues between side chains. Our data provide direct evidence of a previously proposed glucomannan backbone, but draw into question previously proposed side-chain structures.