Antibiotics and antiseptics for venous leg ulcers

Antibiotic Misuse in Wound Care: Can Bacterial Localization through Fluorescence Imaging Help?

(1) Background: Systemic antibiotic use in chronic wounds is alarmingly high worldwide. Between 53% to 71% of patients are prescribed at least one course per chronic wound. Systemic antibiotic use should follow antibiotic stewardship guidelines and ought to be reserved for situations where their use is deemed supported by clinical indications. Unfortunately, in the field of wound care, indiscriminate and often inadequate use of systemic antibiotics is leading to both patient complications and worsening antibiotic resistance rates. Implementing novel tools that help clinicians prevent misuse or objectively determine the true need for systemic antibiotics is essential to reduce prescribing rates. (2) Methods: We present a compendium of available systemic antibiotic prescription rates in chronic wounds. The impact of various strategies used to improve these rates, as well as preliminary data on the impact of implementing fluorescence imaging technology to finesse wound status diagnosis, are presented. (3) Results: Interventions including feedback from wound care surveillance and treatment data registries as well as better diagnostic strategies can ameliorate antibiotic misuse. (4) Conclusions: Interventions that mitigate unnecessary antibiotic use are needed. Effective strategies include those that raise awareness of antibiotic overprescribing and those that enhance diagnosis of infection, such as fluorescence imaging.

In vitro Activity of Antimicrobial Wound Dressings on P. aeruginosa Wound Biofilm

The treatment of acute and chronic infected wounds with residing biofilm still poses a major challenge in medical care. Interactions of antimicrobial dressings with bacterial load, biofilm matrix and the overall protein-rich wound microenvironment remain insufficiently studied. This analysis aimed to extend the investigation on the efficacy of a variety of antimicrobial dressings using an in vitro biofilm model (lhBIOM) mimicking the specific biofilm-environment in human wounds. Four wound dressings containing polyhexanide (PHMB), octendine di-hydrochloride (OCT), cadexomer-iodine (C-IOD) or ionic silver (AG) were compared regarding their antimicrobial efficacy. Quantitative analysis was performed using a quantitative suspension method, separately assessing remaining microbial counts within the solid biofilm as well as the dressing eluate (representing the absorbed wound exudate). Dressing performance was tested against P. aeruginosa biofilms over the course of 6 days. Scanning electron microscopy (SEM) was used to obtain qualitative visualization on changes in biofilm structure. C-IOD demonstrated superior bacterial reduction. In comparison it was the only dressing achieving a significant reduction of more than 7 log₁₀ steps within 3 days. Neither the OCT- nor the AG-containing dressing exerted a distinct and sustained antimicrobial effect. PHMB achieved a non-significant microbicidal effect (1.71 ± 0.31 log₁₀ steps) at day 1. Over the remaining course (6 days) it demonstrated a significant microbistatic effect compared to OCT, AG and the control. Quantitative results in the dressing eluate correlate with those of the solid biofilm model. Overall, AG- and OCT-containing dressings did not achieve the expected anti-biofilm efficacy, while C-IOD performed best. Chemical interaction with the biofilms extrapolymeric substance (EPS), visualized in the SEM, and dressing configuration (agent concentration and release pattern) are suspected to be responsible. The unexpected low and diverse results of the tested antimicrobial dressings indicate a necessity to rethink non-debridement anti-biofilm therapy. Focussing on the combination of biofilm-disruptive (for EPS structure) and antimicrobial (for residing microorganisms) features, as with C-IOD, using dehydration and iodine, appears reasonably complementary and an optimal solution, as suggested by the here presented in vitro data.

Beyond conventional antibiotics - New directions for combination products to combat biofilm

Medical device related infections are a significant and growing source of morbidity and mortality. Biofilm formation is a common feature of medical device infections that is not effectively prevented or treated by systemic antibiotics. Antimicrobial medical device combination products provide a pathway for local delivery of antimicrobial therapeutics with the ability to achieve high local concentrations while minimizing systemic side effects. In this review, we present considerations for the design of local antimicrobial delivery systems, which can be facilitated by modeling local pharmacokinetics in the context of the target device application. In addition to the need for local delivery, a critical barrier to progress in the field is the need to incorporate agents effective against biofilm. This article aims to review key properties of antimicrobial peptides that make them well suited to meet the demands of the next generation of antimicrobial medical devices, including broad spectrum activity, rapid and biocidal mechanisms of action, and efficacy against biofilm.

Diluted honey inhibits biofilm formation: potential application in urinary catheter management?

Aims

Biofilms are ubiquitous and when mature have a complex structure of microcolonies in an extracellular polysaccharide and extracellular DNA matrix. Indwelling medical devices harbour biofilms which have been shown to cause infections and act as reservoirs for pathogens. Urinary catheters are often in place for considerable periods of time and are susceptible to both encrustation and biofilm formation. Strategies for minimising biofilm occurrence underpin an active research area in biomedicine. Manuka honey has, inter alia, well-established antibacterial properties. This study aims to assess the influence of honey on early biofilm formation in an established in vitro model.

Methods

An established model of early biofilm formation using static bacterial cultures in vinyl 96-well plates was used to grow Escherichia coli, strain ATC 25922 and Proteus mirabilis, strain 7002. Planktonic cells were removed and the residual biofilm was stained with crystal violet, which were subsequently eluted and quantified spectrophotometrically. Manuka honey (Unique Manuka Factor 15+) was added either with the bacteria or up to 72 hours after.

Results

Biofilms in this model was developed over 3 days, after which growth stalled. Mixed (1:1) cultures of E. coli and P. mirabilis grew slower than monocultures. In mixed cultures, honey gave a dose-dependent reduction in biofilm formation (between 3.3 and 16.7%w/v). At 72 hours, all concentrations inhibited maximally (p<0.001). Application of honey to cultures after 24 and 48 hours also reduced the adherent bacterial biomass (p<0.05–p<0.01).

Conclusion

Manuka honey at dilutions as low as 3.3% w/v in some protocols and at 10% or above in all protocols tested significantly inhibits bacterial attachment to a vinyl substrate and reduces further early biofilm development. No augmentation of growth over untreated controls was observed in any experiment.

Wounds research for patient benefit: a 5-year programme of research

Background

Complex wounds are those that heal by secondary intention and include lower-limb ulcers, pressure ulcers and some surgical wounds. The care of people with complex wounds is costly, with care mainly being delivered by community nurses. There is a lack of current, high-quality data regarding the numbers and types of people affected, care received and outcomes achieved.

Objectives

To (1) assess how high-quality data about complex wounds can be captured effectively for use in both service planning and research while ensuring integration with current clinical data collection systems and minimal impact on staff time; (2) investigate whether or not a clinical register of people with complex wounds could give valid estimates of treatment effects, thus reducing dependence on large-scale randomised controlled trials (RCTs); (3) identify the most important research questions and outcomes for people with complex wounds from the perspectives of patients, carers and health-care professionals; (4) evaluate the potential contributions to decision-making of individual patient data meta-analysis and mixed treatment comparison meta-analysis; and (5) complete and update systematic reviews in topic areas of high priority.

Methods

To meet objectives 1 and 2 we conducted a prevalence survey and developed and piloted a longitudinal disease register. A consultative, deliberative method and in-depth interviews were undertaken to address objective 3. To address objectives 4 and 5 we conducted systematic reviews including mixed treatment comparison meta-analysis.

Results

From the prevalence survey we estimated the point prevalence of all complex wounds to be 1.47 per 1000 people (95% confidence interval 1.38 to 1.56 per 1000 people). Pressure ulcers and venous leg ulcers were the most common type of complex wound. A total of 195 people with a complex wound were recruited to a complex wounds register pilot. We established the feasibility of correctly identifying, extracting and transferring routine NHS data into the register; however, participant recruitment, data collection and tracking individual wounds in people with multiple wounds were challenging. Most patients and health professionals regarded healing of the wound as the primary treatment goal. Patients were greatly troubled by the social consequences of having a complex wound. Complex wounds are frequently a consequence of, and are themselves, a long-term condition but treatment is usually focused on healing the wound. Consultative, deliberative research agenda setting on pressure ulcer prevention and treatment with patients, carers and clinicians yielded 960 treatment uncertainties and a top 12 list of research priorities. Of 167 RCTs of complex wound treatments in a systematic review of study quality, 41% did not specify a primary outcome and the overall quality of the conduct and reporting of the research was poor. Mixed-treatment comparison meta-analysis in areas of high priority identified that matrix hydrocolloid dressings had the highest probability (70%) of being the most effective dressing for diabetic foot ulcers, whereas a hyaluronan fleece dressing had the highest probability (35%) of being the most effective dressing for venous ulcers; however, the quality of this evidence was low and uncertainty is high.

Conclusions

Complex wounds are common and costly with a poor evidence base for many frequent clinical decisions. There is little routine clinical data collection in community nursing. A prospective complex wounds register has the potential to both assist clinical decision-making and provide important research evidence but would be challenging to implement without investment in information technology in NHS community services. Future work should focus on developing insights into typical wound healing trajectories, identifying factors that are prognostic for healing and assessing the cost-effectiveness of selected wound treatments.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

The effect of honey gel on abdominal wound healing in cesarean section: a triple blind randomized clinical trial

OBJECTIVE

To assess whether honey can accelerate the wound healing in women undergoing cesarean section.

METHODS

This was a triple blinded randomized prospective clinical trial. Women with cesarean section were randomly designated as drug (37 cases) and placebo (38 cases) groups. The drug group received local honey gel 25% while the placebo group received similar free-honey gel on abdominal cesarean incision twice a day for 14 days. REEDA scale (Redness, Edema, Ecchymosis, Discharge and Approximation of wound edges) was used to assess wound healing.

RESULTS

The mean REEDA was 2.27 ± 2.46 and 3.91 ± 2.74 (p=0.008) on the 7(th) day and 0.47 ± 0.84 and 1.59± 1.95 (p=0.002) on the 14(th) day for the drug and placebo groups, respectively. Redness, edema and hematoma in the drug group were significantly lower on the 7(th) and 14(th) days.

CONCLUSION

Honey was effective in healing the cesarean section incision. Using topical honey is suggested as a natural product with rare side effects in order to reduce the complications of cesarean wounds.