A retrospective review of the use of a nanocrystalline silver dressing in the management of open chronic wounds in the community.

As part of an infection management protocol, antimicrobial dressings offer an appropriate, cost-effective choice for the management of localised bioburden in chronic wounds. The choice of antimicrobial can impact significantly not only on the treatment outcomes and cost but also on the safety and well-being of the patient. This retrospective study investigates these outcomes comparing health care records of 2572 patients with open chronic wounds, who were treated either with an Integrated Care Wound Bundle (ICB) including nanocrystalline silver (NCS) dressings (n = 330) or without NCS dressings and not on a ICB (n = 2242) in the community from March 2016 to March 2018. Wounds treated in the NCS dressing treatment bundle had a mean healing time of 10.46 weeks, vs 25.49 weeks for the non-ICB treated wounds. In addition, the average interval time between dressing changes was in favour of the NCS dressing treatment bundle (3.98 vs 1.87 days), contributing to a substantial reduction in mean treatment labour costs ($1251 vs $6488). The use of a NCS dressing demonstrated improved efficacy and cost effectiveness of labour required for chronic wound management; highlighting the importance of choosing an effective antimicrobial dressing as part of an infection management protocol.

Efficacy of topical cadexomer iodine treatment in chronic wounds: Systematic review and meta-analysis of comparative clinical trials.

The aim of this study was to summarise the clinical evidence supporting almost 40 years of topical cadexomer iodine (CIOD) use in wound bed preparation by removing barriers to healing such as exudate, slough, bioburden, and infection and allowing chronic wound progression. A systematic review was conducted (Embase/PubMed, November 2020) to identify relevant comparative studies meeting inclusion criteria. Meta-analyses were performed using a fixed-effects (I2 < 50%) or random-effects model (I2 ≥ 50%) depending on statistical heterogeneity. Dichotomous outcomes were reported as relative risk (RR) and continuous outcomes as mean difference (MD), with 95% confidence intervals. In total, 436 publications were identified of which 13 were comparative trials including outcomes of interest. Significant reductions in exudate, pus/debris, slough, bioburden, and infection were reported in chronic wounds treated with CIOD, compared with standard of care (SOC). Meta-analyses highlighted the positive impact of CIOD on mean wound area reduction (MD = 2.35 cm2 , 95% CI = 0.34-4.36, P = .0219) after eight weeks treatment and overall wound healing events compared to SOC; wounds including venous leg ulcers, diabetic foot ulcers, and pressure ulcers treated with CIOD were more than twice as likely to heal than those receiving SOC (RR = 2.30, 95% CI = 1.54-3.45, P < .0001). This meta-analysis demonstrates the efficacy of CIOD on chronic wounds through removal of barriers to healing. CIOD should be considered in wound bed preparation and treatment protocols.

Cadexomer iodine effectively reduces bacterial biofilm in porcine wounds ex vivo and in vivo.

Biofilms are prevalent in non-healing chronic wounds and implicated in delayed healing. Tolerance to antimicrobial treatments and the host's immune system leave clinicians with limited interventions against biofilm populations. It is therefore essential that effective treatments be rigorously tested and demonstrate an impact on biofilm across multiple experimental models to guide clinical investigations and protocols. Cadexomer iodine has previously been shown to be effective against biofilm in various in vitro models, against methicillin-resistant Staphylococcus aureus biofilm in mouse wounds, and clinically in diabetic foot ulcers complicated by biofilm. Similarities between porcine and human skin make the pig a favoured model for cutaneous wound studies. Two antiseptic dressings and a gauze control were assessed against mature biofilm grown on ex vivo pig skin and in a pig wound model. Significant reductions in biofilm were observed following treatment with cadexomer iodine across both biofilm models. In contrast, silver carboxymethylcellulose dressings had minimal impact on biofilm in the models, with similar results to the control in the ex vivo model. Microscopy and histopathology indicate that the depth of organisms in wound tissue may impact treatment effectiveness. Further work on the promising biofilm efficacy of cadexomer iodine is needed to determine optimal treatment durations against biofilm.

Appropriate use of dressings containing nanocrystalline silver to support antimicrobial stewardship in wounds.

Antimicrobial resistance is an ever-increasing global concern, with the era of untreatable infection becoming a reality. Wound care is no exception, with increasing issues of antibiotic-resistant infections across different wound types and care settings. Antibiotic resistance and stewardship have been the priority for most strategic interventions so far; however, in wound care, alternative or supplementary strategies using antiseptics should be considered. Antiseptics such as silver can provide effective cidal activity across a broad range of wound pathogens, assuming they are used at the correct level for an appropriate duration. Evidence summarised in this manuscript suggests that effective antiseptics, such as nanocrystalline silver, have an increasing body of evidence in support of their use to minimise transmission of antibiotic-resistant organisms as part of institutional infection control procedures and, in addition, through appropriate early use and stewardship on local wound infections, in conjunction with local procedures, to minimise the need for systemic antibiotic therapy. Engagement, alignment, and collaboration between wound care professionals and wider related teams and governments on antimicrobial stewardship, and the potential role of antiseptics within this, will help to generate further evidence for such interventions in the fight against antimicrobial-resistant infections in wound care.

Colonization of mucin by human intestinal bacteria and establishment of biofilm communities in a two-stage continuous culture system.

The human large intestine is covered with a protective mucus coating, which is heavily colonized by complex bacterial populations that are distinct from those in the gut lumen. Little is known of the composition and metabolic activities of these biofilms, although they are likely to play an important role in mucus breakdown. The aims of this study were to determine how intestinal bacteria colonize mucus and to study physiologic and enzymatic factors involved in the destruction of this glycoprotein. Colonization of mucin gels by fecal bacteria was studied in vitro, using a two-stage continuous culture system, simulating conditions of nutrient availability and limitation characteristic of the proximal (vessel 1) and distal (vessel 2) colon. The establishment of bacterial communities in mucin gels was investigated by selective culture methods, scanning electron microscopy, and confocal laser scanning microscopy, in association with fluorescently labeled 16S rRNA oligonucleotide probes. Gel samples were also taken for analysis of mucin-degrading enzymes and measurements of residual mucin sugars. Mucin gels were rapidly colonized by heterogeneous bacterial populations, especially members of the Bacteroides fragilis group, enterobacteria, and clostridia. Intestinal bacterial populations growing on mucin surfaces were shown to be phylogenetically and metabolically distinct from their planktonic counterparts.

Microbiological effects of consuming a synbiotic containing Bifidobacterium bifidum, Bifidobacterium lactis, and oligofructose in elderly persons, determined by real-time polymerase chain reaction and counting of viable bacteria.

BACKGROUND: Because of changes in gut physiology, immune system reactivity, and diet, elderly people are more susceptible to gastrointestinal infections than are younger adults. The gut microflora, which provides a natural defense against invading microorganisms, changes in elderly people with the development of potentially damaging bacterial populations, which may lead to alterations in bacterial metabolism and higher levels of infection. METHODS: A randomized, double-blind, controlled feeding trial was done with 18 healthy elderly volunteers (age, >62 years) using a synbiotic comprising Bifidobacterium bifidum BB-02 and Bifidobacterium lactis BL-01 (probiotics) together with an inulin-based prebiotic (Synergy 1; Orafti). Real-time PCR was employed to quantitate total bifidobacteria, B. bifidum, and B. lactis in fecal DNA before, during, and after synbiotic consumption. Counting all viable anaerobes, bifidobacteria, and lactobacilli and identification of bacterial isolates to species level was also done. RESULTS: Throughout feeding, both bifidobacteria species were detected in fecal samples obtained from all subjects receiving the synbiotic, with significant increases in the number of copies of the 16S rRNA genes of B. bifidum, B. lactis, and total bifidobacteria, compared with the control week and the placebo group. At least 1 of these species remained detectable in fecal samples 3 weeks after feeding in individuals that had no fecal B. bifidum and/or B. lactis in the control week, indicating that the probiotics persisted in the volunteers. Counting of viable organisms showed significantly higher total numbers of fecal bifidobacteria, total numbers of lactobacilli, and numbers of B. bifidum during synbiotic feeding. CONCLUSION: Synbiotic consumption increased the size and diversity of protective fecal bifidobacterial populations, which are often very much reduced in older people.

Comparison of compositions and metabolic activities of fecal microbiotas in young adults and in antibiotic-treated and non-antibiotic-treated elderly subjects.

The colonic microbiota mediates many cellular and molecular events in the host that are important to health. These processes can be affected in the elderly, because in some individuals, the composition and metabolic activities of the microbiota change with age. Detailed characterizations of the major groups of fecal bacteria in healthy young adults, in healthy elderly people, and in hospitalized elderly patients receiving antibiotics were made in this study, together with measurements of their metabolic activities, by analysis of fecal organic acid and ammonia concentrations. The results showed that total anaerobe numbers remained relatively constant in old people; however, individual bacterial genera changed markedly with age. Reductions in numbers of bacteroides and bifidobacteria in both elderly groups were accompanied by reduced species diversity. Bifidobacterial populations in particular showed marked variations in the dominant species, with Bifidobacterium angulatum and Bifidobacterium adolescentis being frequently isolated from the elderly and Bifidobacterium longum, Bifidobacterium catenulatum, Bifidobacterium boum, and Bifidobacterium infantis being detected only from the healthy young volunteers. Reductions in amylolytic activities of bacterial isolates in healthy elderly subjects and reduced short-chain fatty acid concentrations supported these findings, since bifidobacteria and bacteroides are important saccharolytic groups in the colon. Conversely, higher numbers of proteolytic bacteria were observed with feces samples from the antibiotic-treated elderly group, which were also associated with increased proteolytic species diversity (fusobacteria, clostridia, and propionibacteria). Other differences in the intestinal ecosystem in elderly subjects were observed, with alterations in the dominant clostridial species in combination with greater numbers of facultative anaerobes.