Diabetic foot infections: A need for innovative assessments

Assessing Pediatric Burn Wound Infection Using a Point-of-Care Fluorescence Imaging Device

Wound infection is the most common complication among pediatric burn patients. When not treated promptly, burn wound infection may lead to delayed healing, failure of skin grafts, or death. Standard burn wound assessment includes inspection for visual signs and symptoms of infection (VSSI) and microbial sampling. To aid in the assessment of burn wound infection, the MolecuLight, a point-of-care autofluorescence imaging device, was introduced at our pediatric burn program in 2020. The MolecuLight uses violet light to illuminate the wound bed, causing clinically relevant quantities of 29 different species of bacteria (>104 CFU/g) to fluoresce in real time. The objectives of this study were to evaluate the role of the MolecuLight in the management of pediatric burn wounds and determine if the findings from the MolecuLight corresponded to VSSI and/or microbial sampling. A retrospective review of patients 0-18 years who had burn wounds assessed with the MolecuLight between November 1, 2020 and June 8, 2023 was conducted. Data were extracted from the medical records of 178 eligible patients with 218 wounds imaged with the device. Fluorescence corresponded with VSSI in 81% of wounds and microbial findings in 82% of wounds. MolecuLight fluorescence, in combination with VSSI, improved sensitivity for detecting wound infections by 39% and decreased specificity by 19% compared to visual signs and symptoms in isolation. Incorporation of the MolecuLight in standard burn wound assessments can improve the detection of infections, which may promote improved wound healing outcomes and antimicrobial stewardship.

Inhibitory activity of flavonoids fraction from Astragalus membranaceus Fisch. ex Bunge stems and leaves on Bacillus cereus and its separation and purification

Introduction: Astragalus membranaceus Fisch. ex Bunge is a traditional botanical drug with antibacterial, antioxidant, antiviral, and other biological activities. In the process of industrialization of A. membranaceus, most of the aboveground stems and leaves are discarded without resource utilization except for a small amount of low-value applications such as composting. This study explored the antibacterial activity of A. membranaceus stem and leaf extracts to evaluate its potential as a feed antibiotic substitute. Materials and methods: The antibacterial activity of the flavonoid, saponin, and polysaccharide fractions in A. membranaceus stems and leaves was evaluated by the disk diffusion method. The inhibitory activity of the flavonoid fraction from A. membranaceus stems and leaves on B. cereus was explored from the aspects of the growth curve, cell wall, cell membrane, biofilm, bacterial protein, and virulence factors. On this basis, the flavonoid fraction in A. membranaceus stems and leaves were isolated and purified by column chromatography to determine the main antibacterial components. Results: The flavonoid fraction in A. membranaceus stems and leaves had significant inhibitory activity against B. cereus, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 1.5625 and 6.25 mg/mL, respectively. A. membranaceus stem and leaf flavonoid fraction can induce death of B. cereus in many ways, such as inhibiting growth, destroying cell wall and cell membrane integrity, inhibiting biofilm formation, inhibiting bacterial protein synthesis, and downregulating virulence factor expression. In addition, it was clear that the main flavonoid with antibacterial activity in A. membranaceus stems and leaves was isoliquiritigenin. Molecular docking showed that isoliquiritigenin could form a hydrogen bonding force with FtsZ. Conclusion: A. membranaceus stem and leaf flavonoid fractions had significant inhibitory activity against B. cereus, and the main chemical composition was isoliquiritigenin.

Synthesis of poly-tetrahydropyrimidine antibacterial polymers and research of their basic properties

Modern medicine has increasingly higher requirements for antibacterial materials. To overcome this challenge, we use alkynyl monomers, amino monomers, formaldehyde, and acetic acid as raw materials to synthesize a series of poly-tetrahydropyrimidine (P-THP) polymers through multicomponent polymerizations (MCPs). P-THP polymers can effectively inhibit the growth of Gram-positive bacteria (Staphylococcus aureus, S. aureus) and Gram-negative bacteria (Escherichia. coli, E. coli), and can prevent bacteria from developing drug resistance within at least 16 generations. Besides, we prepared P-THP antibacterial coatings and explored their antibacterial properties. In vitro antibacterial experiments showed that P-THP coatings can prevent the formation of bacterial biofilms, and the coatings have a lasting killing effect on E. coli and S. aureus. The mouse wound infection experiments proved that P-THP polymers can significantly accelerate skin tissue regeneration and wound healing. Moreover, the P-THP textile obtained by electrospinning also has antibacterial properties and has great application prospects in the field of N95 masks. Generally speaking, P-THP polymers have considerable application potential in the field of treating bacterial infections and promoting wound healing.

Antibacterial and antibiofilm activities of Mayan medicinal plants against Methicillin-susceptible and -resistant strains of Staphylococcus aureus

ETHNOPHARMACOLOGICAL RELEVANCE

Several medicinal plants are used in Mayan Traditional Medicine to treat skin, urinary, respiratory, and gastrointestinal infectious diseases. However, scientific studies that have supported the bioactivity of these Mayan medicinal plants are limited.

AIM OF THE STUDY

To assess the in-vitro anti-Staphylococcus aureus growth and biofilm-formation activities of 15 Mayan medicinal plants that were selected based on their traditional uses for the treatment of infectious diseases.

MATERIALS AND METHODS

Mayan medicinal plants used traditionally to treat infectious diseases were preselected. For each part of the plants, four extracts were prepared with different solvents (water, n-hexane, ethyl acetate, and methanol). These were tested against two reference strains: a Methicillin-susceptible and -resistant S. aureus, and two clinical isolates, including a susceptible and multidrug-resistant S. aureus using a Resazurin Microtiter Assay. In addition, the plant extracts were evaluated in biofilm-formation inhibition on S. aureus by means of the Crystal Violet method.

RESULTS

A total of 120 extracts from 15 Mayan medicinal plant species belonging to 12 different families were selected according their ethnopharmacological uses to treat infectious diseases. Among the selected plant species, 26 extracts obtained from eight medicinal Mayan plants exhibited significant anti-S. aureus against the four strains tested. The most active extracts were the Aq (aqueous) leaf extract of Krugiodendron ferreum (Minimal Inhibitory Concentration [MIC] = 125-250 μg/mL), the MeOH bark extracts of Matayba oppositifolia, Clusia flava, Gymnopodium floribundum, the MeOH leaf extract of Spondias purpurea with MIC values of 250 μg/mL, and the MeOH leaf and Aq bark extracts of K. ferreum (MIC = 250-500 μg/mL). Among the active extracts, 12 exhibited a bactericidal effect on S. aureus strains (Minimal Bactericidal Concentration [MBC] = 250-1000 μg/mL). Forty extracts from 13 plants have an effect on the anti-formation of biofilm, the most active were the MeOH leaf extract of M. oppositifolia (one-half Inhibitory Concentration [IC₅₀] = 10.4 μg/mL) and the MeOH (IC₅₀ = 17.7 μg/mL) and Hex (18.2 μg/mL) leaf extracts from S. purpurea.

CONCLUSION

Aqueous and organic extracts from Mayan medicinal plants showed bactericidal and anti-biofilm activities even against drug-resistant S. aureus strains. The present study supports the traditional usage of some plants employed in Mayan medicine for illnesses such as skin, gastrointestinal, and urinary infections and suggest that these plants could be a good source of antibacterial phytochemicals.

Culturomics Approach to Identify Diabetic Foot Infection Bacteria

The main goal of the study was to evaluate the usefulness of the culturomics approach in the reflection of diabetic foot infections (DFIs) microbial compositions in Poland. Superficial swab samples of 16 diabetic foot infection patients (Provincial Polyclinical Hospital in Toruń, Poland) were subjected to culturing using 10 different types of media followed by the identification via the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and Biotyper platform. Identified 204 bacterial isolates representing 18 different species—mostly Enterococcus faecalis (63%) and Staphylococcus aureus (44%). Most of the infections (81%) demonstrated a polymicrobial character. Great differences in the species coverage, the number of isolated Gram-positive and Gram-negative bacteria, and the efficiency of the microbial composition reflection between the investigated media were revealed. The use of commonly recommended blood agar allowed to reveal only 53% of the entire microbial composition of the diabetic foot infection samples, which considerably improved when the chromagar orientation and vancomycin-resistant enterococi agar were applied. In general, efficiency increased in the following order: selective < universal < enriched < differential media. Performed analysis also revealed the impact of the culture media composition on the molecular profiles of some bacterial species, such as Corynebacterium striatum, Proteus mirabilis or Morganella morganii that contributed to the differences in the identification quality. Our results indicated that the culturomics approach can significantly improve the accuracy of the reflection of the diabetic foot infections microbial compositions as long as an appropriate media set is selected. The chromagar orientation and vancomycin-resistant enterococi agar media which were used for the first time to study diabetic foot infection microbial profiles demonstrate the highest utility in the culturomics approach and should be included in further studies directed to find a faster and more reliable diabetic foot infection diagnostic tool.

Utility of MolecuLight i:X for Managing Bacterial Burden in Pediatric Burns

Pediatric burn injuries are vulnerable to severe complications, most often infection, making prompt and precise diagnosis of bacterial bioburden vital to preventing detrimental consequences and optimizing patients' outcomes. Currently, burn wounds are assessed for infection via examining the clinical signs and symptoms of infection, which can be confirmed by swab culture analysis. While the former approach is subjective and experience-dependant, the latter technique is susceptible to missing subsurface, biofilm-associated colonization, and any peripheral bacterial burden, and also delays confirmation by up to 5 days. The MolecuLight i:X is a handheld, noncontact fluorescence imaging device, which can reveal real-time information about clinically significant levels of bacteria and their biodistribution in surface and subsurface burn wound tissues. We conducted a single-center observational study to assess the device efficacy in identifying critical bacterial levels in pediatric burn wounds and to test the children's compliance and the overall feasibility of the device integration into the current diagnostic practice. Ten patients with 16 wounds were recruited and assessed for the presence or absence of clinical signs and symptoms of infection and the presence or absence of bacterial fluorescence on images, with swabs taken to confirm findings. Results demonstrate the device's ability to visualize clinically significant bacterial burden and to localize distribution of pathogens. All clinicians agreed on the high compliance with the device and high feasibility of incorporating the device into routine wound assessments. The results of this study may pave the way toward including bacterial fluorescence imaging into the standard diagnostic algorithm for pediatric burn population.

Principles of Best Diagnostic Practice in Tissue Repair and Wound Healing: An Expert Consensus

Chronic wound treatment currently relies heavily on visual assessment by clinicians; however, the clinical signs and symptoms of infection and inflammation are unreliable in chronic wounds. The specialty of wound care has witnessed the advent of advanced interventions, such as cellular and/or tissue based products (CTP). The success of advanced therapies relies on preparing the wound bed by reducing bacterial burden and inflammation. The lack of diagnostics in chronic wound care leads to uncertainty in the adequacy of wound bed preparation. Recent research suggests that two novel point-of-care diagnostic tests can assist in the detection of chronic inflammation known as elevated neutrophil derived protease activity (EPA) and bacterial pathogenesis known as bacterial protease activity(BPA) in chronic wounds. Despite the evidence, however, clinicians report that incorporating diagnostics into every day practice is challenging and across the globe, they have requested guidance on their use. Methods and Recommendations: A panel of wound care experts, experienced with these tests, met to develop guidelines on their use in wound care practice. The consensus panel concluded that the clinician should test for BPA first. The panel maintained that the risk of invasive infection resulting from the presence of pathogenic bacteria was the greatest threat to the patient's health. If the BPA test is negative, the panel recommended testing for EPA. In addition, it was suggested that if the wound failed to progress after the elevated BPA was treated and subsequent testing was negative for BPA, the clinician should consider testing for EPA. Conclusions: In this manuscript, the consensus panel suggests pathways for testing, treating, and retesting for EPA and BPA. The panel expects that following the algorithm has the potential to improve healing outcomes, result in more cost-effective use of advanced therapies, and improve antimicrobial stewardship by guiding antimicrobial use.

A novel intraoperative technique seeding morselized bone tissue into pediatric blood culture bottles improves microbiological diagnosis in patients with foot and ankle osteomyelitis

BACKGROUND

Osteomyelitis, particularly cases involving the foot and ankle, is a challenging situation that frequently leads to amputations and major sequelae. Targeted antibiotics treating an identified pathogen are key to a successful outcome; however, traditional culture methods for bone tissue have poor sensitivity. This study prospectively compared a novel method for obtaining and processing infected bone tissue with the standard technique.

METHODS

107 patients presenting with a diagnosis of osteomyelitis of the foot and ankle between 2008 and 2017 were prospectively included. Diagnosis was done according to clinical, laboratory and imaging findings. We obtained paired samples of bone tissue from all patients; they were processed through a usual culture method (UCM), but they were also morselized and seeded into pediatric blood culture bottles (PBCBs). We compared the culture yield and the number of agents detected using both the McNemar and the Mann-Whitney tests, respectively.

RESULTS

We studied 107 patients (63 with diabetic foot infection and 44 with nondiabetic osteomyelitis). The causative agent was identified in 60.7% of cases using the UCM and in 97.2% of cases using PBCBs (p < 0.001). We detected a mean of 1.05 ± 1.03 bacteria using the UCM and 1.67 ± 0.92 bacteria using PBCBs (p < 0.01).

CONCLUSION

Cultures using morselized bone seeded in PBCBs identified the causative agent in a significantly larger percentage than the UCM. Additionally, this method identified a larger number of pathogen agents. A better agent identification method has advantages such as identifying more specific antibiotic treatment in these cases.

Pexiganan in Combination with Nisin to Control Polymicrobial Diabetic Foot Infections

Diabetic foot ulcers (DFUs) are major complications of Diabetes mellitus being responsible for significant morbidity and mortality. DFUs frequently become chronically infected by a complex community of bacteria, including multidrug-resistant and biofilm-producing strains of Staphylococcus aureus and Pseudomonas aeruginosa. Diabetic foot infections (DFI) are often recalcitrant to conventional antibiotics and alternative treatment strategies are urgently needed. Antimicrobial Peptides (AMPs), such as pexiganan and nisin, have been increasingly investigated and reported as effective antimicrobial agents. Here, we evaluated the antibacterial potential of pexiganan and nisin used in combination (dual-AMP) to control the growth of planktonic and biofilm co-cultures of S. aureus and P. aeruginosa clinical strains, co-isolated from a DFU. A DFU collagen three-dimensional (3D) model was used to evaluate the distribution and efficacy of AMPs locally delivered into the model. The concentration of pexiganan required to inhibit and eradicate both planktonic and biofilm-based bacterial cells was substantially reduced when used in combination with nisin. Moreover, incorporation of both AMPs in a guar gum delivery system (dual-AMP biogel) did not affect the dual-AMP antimicrobial activity. Importantly, the application of the dual-AMP biogel resulted in the eradication of the S. aureus strain from the model. In conclusion, data suggest that the local application of the dual-AMPs biogel constitutes a potential complementary therapy for the treatment of infected DFU.

The Cutaneous Microbiome and Wounds: New Molecular Targets to Promote Wound Healing

The ecological community of microorganisms in/on humans, termed the microbiome, is vital for sustaining homeostasis. While culture-independent techniques have revealed the role of the gut microbiome in human health and disease, the role of the cutaneous microbiome in wound healing is less defined. Skin commensals are essential in the maintenance of the epithelial barrier function, regulation of the host immune system, and protection from invading pathogenic microorganisms. In this review, we summarize the literature derived from pre-clinical and clinical studies on how changes in the microbiome of various acute and chronic skin wounds impact wound healing tissue regeneration. Furthermore, we review the mechanistic insights garnered from model wound healing systems. Finally, in the face of growing concern about antibiotic-resistance, we will discuss alternative strategies for the treatment of infected wounds to improve wound healing and outcomes. Taken together, it has become apparent that commensals, symbionts, and pathogens on human skin have an intimate role in the inflammatory response that highlights several potential strategies to treat infected, non-healing wounds. Despite these promising results, there are some contradictory and controversial findings from existing studies and more research is needed to define the role of the human skin microbiome in acute and chronic wound healing.

Local Antibiotic Delivery Systems: Current and Future Applications for Diabetic Foot Infections

Foot infections are common among diabetic patients with peripheral neuropathy and/or peripheral arterial disease, and it can be the pivotal event leading to a minor or major amputation of the lower extremity. Treatment of diabetic foot infections, especially deep-seated ones, remains challenging, in part because impaired blood perfusion and the presence of biofilms can impair the effectiveness of systemic antibiotics. The local application of antibiotics is an emerging field in the treatment of diabetic foot infections, with demonstrable advantages. These include delivery of high concentrations of antibiotics in the affected area, limited systemic absorption, and thus negligible side effects. Biodegradable vehicles, such as calcium sulfate beads, are the prototypical system, providing a good elution profile and the ability to be impregnated with a variety of antibiotics. These have largely superseded the nonbiodegradable vehicles, but the strongest evidence available is for calcium bead implantation for osteomyelitis management. Natural polymers, such as collagen sponge, are an emerging class of delivery systems, although thus far, data on diabetic foot infections are limited. There is recent interest in the novel antimicrobial peptide pexiganan in the form of cream, which is active against most of the microorganisms isolated in diabetic foot infections. These are promising developments, but randomized trials are required to ascertain the efficacy of these systems and to define the indications for their use. Currently, the role of topical antibiotic agents in treating diabetic foot infections is limited and outside of routine practice.

Skin and Soft Tissue Infections

The skin is colonized by a diverse collection of microorganisms which, for the most part, peacefully coexist with their hosts. Skin and soft tissue infections (SSTIs) encompass a variety of conditions; in immunocompromised hosts, SSTIs can be caused by diverse microorganisms-most commonly bacteria, but also fungi, viruses, mycobacteria, and protozoa. The diagnosis of SSTIs is difficult because they may commonly masquerade as other clinical syndromes or can be a manifestation of systemic disease. In immunocompromised hosts, SSTI poses a major diagnostic challenge, and clinical dermatological assessment should be initially performed; to better identify the pathogen and to lead to appropriate treatment, etiology should include cultures of lesions and blood, biopsy with histology, specific microbiological analysis with special stains, molecular techniques, and antigen-detection methodologies. Here, we reviewed the epidemiology, pathophysiology, clinical presentation, and diagnostic techniques, including molecular biological techniques, used for SSTIs, with a focus on the immunocompromised host, such as patients with cellular immunodeficiency, HIV, and diabetic foot infection.

Development of a Novel Collagen Wound Model To Simulate the Activity and Distribution of Antimicrobials in Soft Tissue during Diabetic Foot Infection

Diabetes has major implications for public health, with diabetic foot ulcers (DFUs) being responsible for significant morbidity and mortality. A key factor in the development of nonhealing ulcers is infection, which often leads to the development of biofilm, gangrene, and amputation. A novel approach to treating DFUs is the local release of antibiotics from calcium sulfate beads. We have developed a novel model system to study and compare the release and efficacy of antibiotics released locally, using collagen as a substrate for biofilm growth and incorporating serum to mimic the biochemical complexity of the wound environment. We found that our soft-tissue model supports the growth of a robust Pseudomonas aeruginosa biofilm, and that this was completely eradicated by the introduction of calcium sulfate beads loaded with tobramycin or gentamicin. The model also enabled us to measure the concentration of these antibiotics at different distances from the beads and in simulated wound fluid bathing the collagen matrix. We additionally found that a multidrug-resistant Staphylococcus aureus biofilm, nonsusceptible to antibiotics, nonetheless showed an almost 1-log drop in viable counts when exposed to calcium sulfate beads combined with antibiotics. Together, these data suggest that locally applied antibiotics combined with calcium sulfate provide surprising efficacy in diabetic foot infections and offer an effective alternative approach to infection management. Our study additionally establishes our new system as a biochemically and histologically relevant model that may be used to study the effectiveness of a range of therapies locally or systemically for infected DFUs.

Microenvironment and microbiology of skin wounds: the role of bacterial biofilms and related factors

Wound healing is a systemic response to injury that impacts the entire body and not just the site of tissue damage; it represents one of the most complex biological processes. Our knowledge of wound healing continues to evolve and it is now clear that the wound microenvironment plays a crucial role. The interactions between cells and the surface microenvironment, referred to as the "biofilm," contributes to skin homeostasis and healing. Understanding the functional complexity of the wound microenvironment informs how various factors such as age, ischemia, or bacterial infections can impair or arrest the normal healing processes, and it also allows for the possibility of acting therapeutically on healing defects with microenvironment manipulation. Microbes represent a particularly important factor for influencing the wound microenvironment and therefore wound healing. Moreover, the role of infections, particularly those that are sustained by biofilm-forming bacteria, is mutually related to other microenvironment aspects, such as humidity, pH, metalloproteinases, and reactive oxygen species, on which the modern research of new therapeutic strategies is focused. Today, chronic wounds are a rapidly growing health care burden and it is progressively understood that many non-healing wounds might benefit from therapies that target microorganisms and their biofilm communities. There is no doubt that host factors like perfusion impairments, venous insufficiency, pressure issues, malnutrition, and comorbidities strongly impact the healing processes and therefore must be targeted in the therapeutic management, but this approach might be not enough. In this article, we detail how bacterial biofilms and related factors impair wound healing, the reasons they must be considered a treatment target that is as important as the host's local and systemic pathologic conditions, and the latest therapeutic strategies derived from the comprehension of the wound microenvironment.

The diabetic foot in 2015: an overview

In 2015, it can be said that the diabetic foot is no longer the Cinderella of diabetic complications. Thirty years ago there was little evidence-based research taking place on the diabetic foot, and there were no international meetings addressing this topic. Since then, the biennial Malvern Diabetic Foot meetings started in 1986, the American Diabetes Association founded their Foot Council in 1987, and the European Association for the Study of Diabetes established a Foot Study Group in 1998. The first International Symposium on the Diabetic Foot in The Netherlands was convened in 1991, and this was soon followed by the establishment of the International Working Group on the Diabetic Foot that has produced useful guidelines in several areas of investigation and the management of diabetic foot problems. There has been an exponential rise in publications on diabetic foot problems in high impact factor journals, and a comprehensive evidence-base now exists for many areas of treatment. Despite the extensive evidence available, it, unfortunately, remains difficult to demonstrate that most types of education are efficient in reducing the incidence of foot ulcers. However, there is evidence that education as part of a multi-disciplinary approach to diabetic foot ulceration plays a pivotal role in incidence reduction. With respect to treatment, strong evidence exists that offloading is the best modality for healing plantar neuropathic foot ulcers, and there is also evidence from two randomized controlled trials to support the use of negative-pressure wound therapy in complex post-surgical diabetic foot wounds. Hyperbaric oxygen therapy exhibits the same evidence level and strength of recommendation. International guidelines exist on the management of infection in the diabetic foot. Many randomized trials have been performed, and these have shown that the agents studied generally produced comparable results, with the exception of one study in which tigecycline was shown to be clinically inferior to ertapenem ± vancomycin. Similarly, there are numerous types of wound dressings that might be used in treatment and which have shown efficacy, but no single type (or brand) has shown superiority over others. Peripheral artery disease is another major contributory factor in the development of ulceration, and its presence is a strong predictor of non-healing and amputation. Despite the proliferation of endovascular procedures in addition to open revascularization, many patients continue to suffer from severely impaired perfusion and exhaust all treatment options. Finally, the question of the true aetiopathogenesis of Charcot neuroarthropathy remains enigmatic, although much work is currently being undertaken in this area. In this area, it is most important to remember that a clinically uninfected, warm, insensate foot in a diabetic patient should be considered as a Charcot foot until proven otherwise, and, as such, treated with offloading, preferably in a cast.

Microbiology of diabetic foot infections: from Louis Pasteur to 'crime scene investigation'

Were he alive today, would Louis Pasteur still champion culture methods he pioneered over 150 years ago for identifying bacterial pathogens? Or, might he suggest that new molecular techniques may prove a better way forward for quickly detecting the true microbial diversity of wounds? As modern clinicians faced with treating complex patients with diabetic foot infections (DFI), should we still request venerated and familiar culture and sensitivity methods, or is it time to ask for newer molecular tests, such as 16S rRNA gene sequencing? Or, are molecular techniques as yet too experimental, non-specific and expensive for current clinical use? While molecular techniques help us to identify more microorganisms from a DFI, can they tell us 'who done it?', that is, which are the causative pathogens and which are merely colonizers? Furthermore, can molecular techniques provide clinically relevant, rapid information on the virulence of wound isolates and their antibiotic sensitivities? We herein review current knowledge on the microbiology of DFI, from standard culture methods to the current era of rapid and comprehensive 'crime scene investigation' (CSI) techniques.

Staphylococcus aureus–Related Diabetic Osteomyelitis

Staphylococcus aureus is the main cause of diabetic foot osteomyelitis (DFO) and can be treated medically or by surgery. We investigated the outcome of consecutive patients with a diagnosis of S aureus DFO retrospectively in 4 hospitals according to the type of management, medical (including debridement at bedside) or surgical. The outcome was classified as either favorable or failure (relapse, impaired wound healing, or amputation). Seventy-four patients with S aureus DFO, including 26 with methicillin-resistant S aureus, were included with a mean duration of follow-up of 21 ± 1 months. As part of the initial treatment, 47% underwent bone surgery followed with a short course of antibiotic. Others were treated with antibiotic therapy alone with bedside debridement. The outcome was favorable for 84% of these patients, with similar rates in the surgical and medical groups (80% vs 87%, P > .05). Patients in the medical group were less frequently hospitalized (49% vs 94%, P < .001) and had a shorter length of hospital stay (17 ± 3 vs 50 ± 12 days, P = .004). Patients in the surgery group received a shorter course of antibiotic therapy (10 ± 2 vs 11 ± 1 weeks, P = .001) with fewer side effects (9% vs 33%, P = .01). The type of management was not associated with subsequent new episode of noncontiguous DFO, which developed in 32% of cases. In conclusion, except significant differences in duration of hospitalization and antibiotic therapy, medical and surgical management of S aureus DFO had similar outcomes with a cure rate >80%.

Diabetic foot ulcers: Part II. Management

The management of diabetic foot ulcers can be optimized by using an interdisciplinary team approach addressing the correctable risk factors (ie, poor vascular supply, infection control and treatment, and plantar pressure redistribution) along with optimizing local wound care. Dermatologists can initiate diabetic foot care. The first step is recognizing that a loss of skin integrity (ie, a callus, blister, or ulcer) considerably increases the risk of preventable amputations. A holistic approach to wound assessment is required. Early detection and effective management of these ulcers can reduce complications, including preventable amputations and possible mortality.

The Human Cathelicidin Antimicrobial Peptide LL-37 as a Potential Treatment for Polymicrobial Infected Wounds

Diabetic patients often have ulcers on their lower-limbs that are infected by multiple biofilm-forming genera of bacteria, and the elimination of the biofilm has proven highly successful in resolving such wounds in patients. To that end, antimicrobial peptides have shown potential as a new anti-biofilm approach. The single human cathelicidin peptide LL-37 has been shown to have antimicrobial and anti-biofilm activity against multiple Gram-positive and Gram-negative human pathogens, and have wound-healing effects on the host. The combination of the anti-biofilm effect and wound-healing properties of LL-37 may make it highly effective in resolving polymicrobially infected wounds when topically applied. Such a peptide or its derivatives could be a platform from which to develop new therapeutic strategies to treat biofilm-mediated infections of wounds. This review summarizes known mechanisms that regulate the endogenous levels of LL-37 and discusses the anti-biofilm, antibacterial, and immunological effects of deficient vs. excessive concentrations of LL-37 within the wound environment. Here, we review recent advances in understanding the therapeutic potential of this peptide and other clinically advanced peptides as a potential topical treatment for polymicrobial infected wounds.

Wound care: biofilm and its impact on the latest treatment modalities for ulcerations of the diabetic foot

Biofilm is an increasingly important topic of discussion in the care of the chronic diabetic foot wound. Treatment modalities have focused on biofilm reduction or eradication through debridement techniques, topical therapies, negative pressure therapy, and ultrasound. In addition, advanced wound healing modalities, such as bioengineered alternative tissues, require optimal wound bed preparation with specific consideration of biofilm reduction before their application. Although fundamental principles of diabetic wound care still apply, critical thought must be given to biofilm before implementing a treatment plan for the closure of these complex wounds.

2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

Clinical application of treating biofilms-associated infections in family medicine

The management of common infections in family medicine may be complicated by poor treatment response or infection recurrence. In many cases, difficulty in treating these infections can be explained by the important role of biofilms, complex microbial communities with unique survival properties that promote infection resistance, recurrence, and persistence. Biofilms have been demonstrated to play important roles in infections involving the sinuses, ears, and ischemic wounds. Biofilms also commonly grow on medical devices, such as indwelling catheters, where they serve as an important nidus of persistent infection. Understanding the role of biofilms in medical infections suggests preventive and treatment strategies that will directly target the important resistive mechanisms of biofilms.

Phagocytic activity is impaired in type 2 diabetes mellitus and increases after metabolic improvement

Objective

1) To evaluate whether peripheral blood mononuclear cells (PBMCs) from type 2 diabetic patients present an impairment of phagocytic activity; 2) To determine whether the eventual impairment in phagocytic activity is related to glycemic control and can be reversed by improving blood glucose levels.

Methods

21 type 2 diabetic patients and 21 healthy volunteers were prospectively recruited for a case-control study. In addition, those patients in whom HbA1c was higher than 8% (n = 12) were hospitalized in order to complete a 5-day intensification treatment of blood glucose. Phagocytic activity was assessed by using a modified flow cytometry procedure developed in our laboratory based on DNA/RNA viable staining to discriminate erythrocytes and debris. This method is simple, highly sensitive and reproducible and it takes advantage of classic methods that are widely used in flow cytometry.

Results

Type 2 diabetic patients showed a lower percentage of activated macrophages in comparison with non-diabetic subjects (54.00±18.93 vs 68.53±12.77%; p = 0.006) Significant negative correlations between phagocytic activity and fasting glucose (r = −0.619, p = 0.004) and HbA1c (r = −0.506, p = 0.019) were detected. In addition, multiple linear regression analyses showed that either fasting plasma glucose or HbA1c were independently associated with phagocytic activity. Furthermore, in the subset of patients who underwent metabolic optimization a significant increase in phagocytic activity was observed (p = 0.029).

Conclusions

Glycemic control is related to phagocytic activity in type 2 diabetes. Our results suggest that improvement in phagocytic activity can be added to the beneficial effects of metabolic optimization.

[The infected diabetic foot]

Infections in the diabetic foot are regularly the consequence of neuropathic, ischemic, or combined neuropathic-ischemic ulcerations which cause substantial morbidity including a high rate of major amputations. Diabetic foot infections are responsible for substantially high costs of diabetic treatment and induce an increased rate of mortality. An early diagnosis on the basis of clinical presentation, laboratory results, and radiologic imaging together with an adequate classification of the severity of infection represents the key for a successful intervention strategy. Severe infections in diabetic feet have a poorer prognosis than mild or moderate infections. A guideline which includes a multifaceted approach to infection control by débridement, antibiotic therapy, and revascularization before definitive reconstruction of the defect may aid in reducing the risk of amputation and improving the quality of life and mobility of the patient. This can be realized by multidisciplinary cooperation. Additional preventive measures such as osseous and soft tissue reconstructions during the infection-free period to establish a plantigrade and ulcer-free foot together with education and routine follow-up controls provide the basis for a long-term reduction of ulcer and infection recurrence with progressive deterioration of the prognosis.

A step-wise approach for surgical management of diabetic foot infections

Diabetic foot disease frequently leads to substantial long-term complications, imposing a huge socioeconomic burden on available resources and health care systems. Peripheral neuropathy, repetitive trauma, and peripheral vascular disease are common underlying pathways that lead to skin breakdown, often setting the stage for limb-threatening infection. Individuals with diabetes presenting with foot infection warrant optimal surgical management to effect limb salvage and prevent amputation; aggressive short-term and meticulous long-term care plans are required. In addition, the initial surgical intervention or series of interventions must be coupled with appropriate systemic metabolic management as part of an integrated, multidisciplinary team. Such teams typically include multiple medical, surgical, and nursing specialties across a variety of public and private health care systems. This article presents a stepwise approach to the diagnosis and treatment of diabetic foot infections with special emphasis on the appropriate use of surgical interventions and includes the following key elements: incision, wound investigation, debridement, wound irrigation and lavage, and definitive wound closure.