When antibiotics can be avoided in skin inflammation and bacterial colonization: a review of topical treatments

Assessment of antibiotic release and antibacterial efficacy from pendant glutathione hydrogels using ex vivo porcine skin

Acute bacterial skin and skin structure infections (ABSSSIs) confer a substantial burden on the healthcare system. Local antibiotic delivery systems can provide controlled drug release directly to the site of infection to maximize efficacy and minimize systemic toxicity. The purpose of this study was to examine the antibacterial activity of antibiotic-loaded glutathione-conjugated poly(ethylene glycol) hydrogels (GSH-PEG) against ABSSSIs utilizing an ex vivo porcine dermal explant model. Vancomycin- or meropenem-loaded GSH-PEG hydrogels at 3 different dose levels were loaded over 1 h. Drug release was monitored in vitro under submerged conditions, by the Franz cell diffusion method, and ex vivo utilizing a porcine dermis model. Antibacterial activity was assessed ex vivo on porcine dermis explants inoculated with Staphylococcus aureus or Pseudomonas aeruginosa isolates treated with vancomycin- or meropenem-loaded GSH-PEG hydrogels, respectively. Histological assessment of the explants was conducted to evaluate tissue integrity and viability in the context of the experimental conditions. A dose-dependent release was observed from vancomycin and meropenem hydrogels, with in vitro Franz cell diffusion data closely representing ex vivo vancomycin release, but not high dose meropenem release. High dose vancomycin-loaded hydrogels resulted in a >3 log10 clearance against all S. aureus isolates at 48 h. High dose meropenem-loaded hydrogels achieved 6.5, 4, and 2 log10 reductions in CFU/ml against susceptible, intermediate, and resistant P. aeruginosa isolates, respectively. Our findings demonstrate the potential application of GSH-PEG hydrogels for flexible, local antibiotic delivery against bacterial skin infections.

Hot topics in reactive oxygen therapy: Antimicrobial and immunological mechanisms, safety and clinical applications

Reactive oxygen species (ROS), when combined with various delivery mechanisms, has the potential to become a powerful novel therapeutic agent against difficult-to-treat infections, especially those involving biofilm. It is important in the context of the global antibiotic resistance crisis. ROS is rapidly active in vitro against all Gram-positive and Gram-negative bacteria tested. ROS also has antifungal and antiviral properties. ROS prevents the formation of biofilms caused by a range of bacterial species in wounds and respiratory epithelium. ROS has been successfully used in infection prevention, eradication of multiresistant organisms, prevention of surgical site infection, and intravascular line care. This antimicrobial mechanism has great potential for the control of bioburden and biofilm at many sites, thus providing an alternative to systemic antibiotics on epithelial/mucosal surfaces, for wound and cavity infection, chronic respiratory infections and possibly recurrent urinary infections as well as local delivery to deeper structures and prosthetic devices. Its simplicity and stability lend itself to use in developing economies as well.

Nanoparticles and nanofibers for topical drug delivery

This review provides the first comprehensive overview of the use of both nanoparticles and nanofibers for topical drug delivery. Researchers have explored the use of nanotechnology, specifically nanoparticles and nanofibers, as drug delivery systems for topical and transdermal applications. This approach employs increased drug concentration in the carrier, in order to increase drug flux into and through the skin. Both nanoparticles and nanofibers can be used to deliver hydrophobic and hydrophilic drugs and are capable of controlled release for a prolonged period of time. The examples presented provide significant evidence that this area of research has - and will continue to have - a profound impact on both clinical outcomes and the development of new products.

Management of traumatic wounds in the Emergency Department: position paper from the Academy of Emergency Medicine and Care (AcEMC) and the World Society of Emergency Surgery (WSES)

Traumatic wounds are one of the most common problems leading people to the Emergency Department (ED), accounting for approximately 5,4 % of all the visits, and up to 24 % of all the medical lawsuits. In order to provide a standardized method for wound management in the ED, we have organized a workshop, involving several Italian and European experts. Later, all the discussed statements have been submitted for external validation to a multidisciplinary expert team, based on the so called Delphi method. Eight main statements have been established, each of them comprising different issues, covering the fields of wound classification, infectious risk stratification, tetanus and rabies prophylaxis, wound cleansing, pain management, and suture. Here we present the results of this work, shared by the Academy of Emergency Medicine and Care (AcEMC), and the World Society of Emergency Surgery (WSES).

Hot topics in the diagnosis and management of skin and soft-tissue infections

Eighteen hot topics regarding the diagnosis and management of skin and soft-tissue infections (SSTIs) were selected and reviewed by members of the SSTI Working Group of the International Society of Chemotherapy (ISC). Despite the large amount of literature available on the issue selected, there are still many unknowns with regard to many of them and further studies are required to answer these challenging issues that face clinicians on a daily basis.

Comparing the Antibacterial and Functional Properties of Cameroonian and Manuka Honeys for Potential Wound Healing-Have We Come Full Cycle in Dealing with Antibiotic Resistance?

The increased incidence of bacterial resistance to antibiotics has generated renewed interest in “traditional” antimicrobials, such as honey. This paper reports on a study comparing physico-chemical, antioxidant and antibacterial characteristics (that potentially contribute in part, to the functional wound healing activity) of Cameroonian honeys with those of Manuka honey. Agar well diffusion was used to generate zones of inhibition against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus while broth dilutions were used to study the minimum inhibitory concentrations (MICs). Non-peroxide activity was investigated by catalase for hydrogen peroxide reduction. The Cameroonian honeys demonstrated functional properties similar to Manuka honey, with strong correlations between the antioxidant activity and total phenol content of each honey. They were also as effective as Manuka honey in reducing bacteria load with an MIC of 10% w/v against all three bacteria and exhibited non-peroxide antimicrobial activity. These Cameroon honeys have potential therapeutic activity and may contain compounds with activity against Gram positive and Gram negative bacteria. Antibacterial agents from such natural sources present a potential affordable treatment of wound infections caused by antibiotic resistant bacteria, which are a leading cause of amputations and deaths in many African countries.

The antimicrobial activity of prototype modified honeys that generate reactive oxygen species (ROS) hydrogen peroxide

BACKGROUND

Antimicrobial resistance continues to be a global issue in healthcare organisations. Honey has long been shown to possess wound healing and antimicrobial properties that are dependent on a number of physical and chemical properties of the honey. We tested the antimicrobial activity of a medicinal honey, Surgihoney® (SH) and two prototype modified honeys made by Apis mellifera (honeybee) against Staphylococcus aureus (NCIMB 9518). We also examined the modified honey prototypes for the ability to generate reactive oxygen species (ROS) by changing the level of production of hydrogen peroxide from the samples.

METHODS

Surgihoney® (SH) was compared with two modified honeys, Prototype 1 (PT1) and Prototype 2 (PT2) using a bioassay method against a standard strain of Staphylococcus aureus. Further work studied the rate of generation of ROS hydrogen peroxide from these preparations.

RESULTS

Surgihoney® antimicrobial activity was shown to be largely due to ROS hydrogen peroxide production. By modification of Surgihoney®, two more potent honey prototypes were shown to generate between a two- and three-fold greater antibacterial activity and up to ten times greater ROS peroxide activity.

CONCLUSIONS

Surgihoney® is a clinically available wound antiseptic dressing that shows good antimicrobial activity. Two further honey prototypes have been shown to have antimicrobial activity that is possible to be enhanced due to demonstrated increases in ROS peroxide activity.