title: Guar gum as a new antimicrobial peptide delivery system against diabetic foot ulcers Staphylococcus aureus isolates.
abstract: Diabetic patients frequently develop diabetic foot ulcers (DFUs), particularly those patients vulnerable to Staphylococcus aureus opportunistic infections. It is urgent to find new treatments for bacterial infections. The antimicrobial peptide (AMP) nisin is a potential candidate, mainly due to its broad spectrum of action against pathogens. Considering that AMP can be degraded or inactivated before reaching its target at therapeutic concentrations, it is mandatory to establish effective AMP delivery systems, with the natural polysaccharide guar gum being one of the most promising. We analysed the antimicrobial potential of nisin against 23 S. aureus DFU biofilm-producing isolates. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were determined for nisin diluted in HCl and incorporated in guar gum gel. Statistical analysis was performed using the Wilcoxon matched-pair test. Nisin was effective against all isolates, including some multidrug-resistant clinical isolates, independent of whether it is incorporated in guar gum. While differences among MIC, MBC and MBIC values were observed for HCl- and guar gum- nisin, no significant differences were found between MBEC values. Inhibitory activity of both systems seems to differ only twofold, which does not compromise guar gum gel efficiency as a delivery system. Our results highlight the potential of nisin as a substitute for or complementary therapy to current antibiotics used for treating DFU infections, which is extremely relevant considering the increase in multidrug-resistant bacteria dissemination. The guar gum gel represents an alternative, practical and safe delivery system for AMPs, allowing the development of novel topical therapies as treatments for bacterial skin infections.
authors: Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal.|Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
authors: Raquel
authors: R
authors: Santos
authors: ISPA Instituto Universitário SA, Lisbon, Portugal.
authors: Diana
authors: D
authors: Gomes
authors: Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal.
authors: Hermes
authors: H
authors: Macedo
authors: Centro de Estudos do Ambiente e do Mar, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
authors: Diogo
authors: D
authors: Barros
authors: Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal.
authors: Catarina
authors: C
authors: Tibério
authors: Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
authors: Ana Salomé
authors: AS
authors: Veiga
authors: Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal.
authors: Luís
authors: L
authors: Tavares
authors: Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
authors: Miguel
authors: M
authors: Castanho
authors: Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal.
authors: Manuela
authors: M
authors: Oliveira
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D017719:Diabetic Foot / Q000382:microbiology*; D004337:Drug Carriers / Q000378:metabolism*; D005685:Galactans / Q000378:metabolism*; D006801:Humans; D008351:Mannans / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D009561:Nisin / Q000494:pharmacology*; D053149:Plant Gums / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D014456:Ulcer / Q000382:microbiology*
chemical_list: D000890:Anti-Infective Agents; D004337:Drug Carriers; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D009561:Nisin; C007894:guar gum