A comparison of the prophylactic uses of topical mupirocin and nitrofurazone in murine crush contaminated wounds

Comparison of Antibacterial Activity and Wound Healing in a Superficial Abrasion Mouse Model of Staphylococcus aureus Skin Infection Using Photodynamic Therapy Based on Methylene Blue or Mupirocin or Both

Background: Antibiotic resistance and impaired wound healing are major concerns in S. aureus superficial skin infections, and new therapies are needed. Antimicrobial photodynamic therapy (aPDT) is a new therapeutic approach for infections, but it also improves healing in many wound models. Objective: To compare the antimicrobial activity and the effects on wound healing of aPDT based on Methylene Blue (MB-aPDT) with mupirocin treatment, either alone or in combination, in superficial skin wounds of S. aureus-infected mice. Additionally, to evaluate the clinical, microbiological, and cosmetic effects on wound healing. Materials and Methods: A superficial skin infection model of S. aureus was established in SKH-1 mice. Infected wounds were treated with MB-aPDT, MB-aPDT with a daily topical mupirocin or only with mupirocin. No treatment was carried out in control animals. Daily clinical and microbiological examinations were performed until complete clinical wound healing. Histopathological studies and statistical analysis were performed at the end of the study. Results: MB-aPDT treatment induced the best wound healing compared to mupirocin alone or to mupirocin plus MB-aPDT. Superficial contraction at 24 h and a greater reduction in size at 48 h, quicker detachment of the crust, less scaling, and absence of scars were observed. Histopathological studies correlated with clinical and gross findings. By contrast, mupirocin showed the highest logaritmic reduction of S. aureus. Conclusions: MB-aPDT and mupirocin treatments are effective in a murine superficial skin infection model of S. aureus. One session of MB-aPDT was the best option for clinical wound healing and cosmetic results. The addition of mupirocin to MB-aPDT treatment improved antimicrobial activity; however, it did not enhance wound healing. No synergistic antibacterial effects were detected.

Next science wound gel technology, a novel agent that inhibits biofilm development by gram-positive and gram-negative wound pathogens

Loss of the skin barrier facilitates the colonization of underlying tissues with various bacteria, where they form biofilms that protect them from antibiotics and host responses. Such wounds then become chronically infected. Topical antimicrobials are a major component of chronic wound therapy, yet currently available topical antimicrobials vary in their effectiveness on biofilm-forming pathogens. In this study, we evaluated the efficacy of Next Science wound gel technology (NxtSc), a novel topical agent designed to kill planktonic bacteria, penetrate biofilms, and kill the bacteria within. In vitro quantitative analysis, using strains isolated from wounds, showed that NxtSc inhibited biofilm development by Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae by inhibiting bacterial growth. The gel formulation NxtSc-G5, when applied to biofilms preformed by these pathogens, reduced the numbers of bacteria present by 7 to 8 log10 CFU/disc or CFU/g. In vivo, NxtSc-G5 prevented biofilm formation for 72 h when applied at the time of wounding and infection and eliminated biofilm infection when applied 24 h after wounding and infection. Storage of NxtSc-G5 at room temperature for 9 months did not diminish its efficacy. These results establish that NxtSc is efficacious in vitro and in vivo in preventing infection and biofilm development by different wound pathogens when applied immediately and in eliminating biofilm infection already established by these pathogens. This novel antimicrobial agent, which is nontoxic and has a usefully long shelf life, shows promise as an effective agent for the prevention and treatment of biofilm-related infections.

Animal models of external traumatic wound infections

BACKGROUND

Despite advances in traumatic wound care and management, infections remain a leading cause of mortality,morbidity and economic disruption in millions of wound patients around the world. Animal models have become standard tools for studying a wide array of external traumatic wound infections and testing new antimicrobial strategies.

RESULTS

Animal models of external traumatic wound infections reported by different investigators vary in animal species used, microorganism strains, the number of microorganisms applied, the size of the wounds and for burn infections, the length of time the heated object or liquid is in contact with the skin.

METHODS

This review covers experimental infections in animal models of surgical wounds, skin abrasions, burns, lacerations,excisional wounds and open fractures.

CONCLUSIONS

As antibiotic resistance continues to increase,more new antimicrobial approaches are urgently needed.These should be tested using standard protocols for infections in external traumatic wounds in animal models.

Efficacy of intraoperative surgical irrigation with polihexanide and nitrofurazone in reducing bacterial load after nail removal surgery

BACKGROUND

A common challenge of nail avulsion surgery is the associated bacterial contamination and infection that can manifest. The toe has a difficult anatomy to antiseptically prepare and properly maintain throughout the surgical procedure, lending to this widespread problem.

OBJECTIVE

We conducted a controlled, prospective randomized study to examine the antiseptic efficacy of 3 intraoperative irrigation methods during nail avulsion surgery.

METHODS

We compared intraoperative antiseptic irrigation using 0.9% saline solution (24 patients), 0.2% nitrofurazone (22 patients), and 0.1% polihexanide (25 patients). Swab samples were taken from each patient at 5 distinct stages throughout the surgical procedure, and bacterial culture analysis was performed (positive culture rate, total inocula count, reduction of bacterial load, and identification of specific micro-organisms).

RESULTS

All 3 intraoperative irrigation methods reduced the total bacterial load, but polihexanide was significantly more effective. Furthermore, no patient from the polihexanide group developed postoperative infection. The reduction in bacterial load was lost for all 3 methods after partial nail avulsion surgery, returning to similar values as the initial presurgical bacterial load. An intraoperative irrigation step after partial nail avulsion with saline, nitrofurazone, and polihexanide was effective in reducing the bacterial load by 95.2%, 96.6%, and 99.5%, respectively.

LIMITATIONS

Our patients underwent phenol-based nail avulsion, resulting in no bacterial load after complete nail removal because of the intrinsic antiseptic nature of the phenol.

CONCLUSIONS

Intraoperative irrigation with 0.1% polihexanide substantially reduced the bacterial load and subsequent infections, highlighting the importance of an irrigation step in nail avulsion surgery.