Local Antibiotics in the Treatment of Diabetic Foot Infections: A Narrative Review

Fabrication of gelatine/fucoidan nanogel-coated silver nanoparticles for the treatment of wound healing therapy and nursing care

Microbial infections and tissue damage by dressing removal are common problems in wound healing. In this study, gelatine/fucoidan nanogel coated with silver nanoparticles (Ag@Gel/Fu) by simple polymerization technique to assess the antibacterial potential Against human infectious pathogens and wound healing activity Against L929 fibroblast cells. The incorporation of silver nanoparticles in Ag@Gel/Fu nanogel was confirmed by UV-vis, XRD, and SEM analysis techniques. The results of the antibacterial assay revealed that the Ag@Gel/Fu nanogel showed excellent bacterial growth reduction and zone of inhibition against Escherichia coli and Staphylococcus aureus, depending upon the concentrations. In vitro wound healing results exhibit rapid regeneration of L929 cells in a short duration. It has more advantages, such as Ag@Gel/Fu, to prevent damage to outer skin tissue by infections. It is the more significant bacterial and biofilm infection control of the wound sites. The overall results confirmed that coating of biopolymer and marine polysaccharide fucoidan enhances the biological property of Ag@Gel/Fu nanogel and wound healing potential. Ag@Gel/Fu nanogel co-culture with fibroblast cells showed no cytotoxic effect after 48 h. Finally, Ag@Gel/Fu nanogel is an effective material for infected wound healing nursing care applications.

A research-based, current approach to diabetes-related acute foot infections and chronic osteomyelitis

INTRODUCTION

Diabetic foot infections (DFIs) and diabetic foot osteomyelitis (DFO) are common and serious complications in patients with diabetes, often leading to severe morbidity (including amputation) and even mortality. Professional footcare, prompt diagnosis and appropriate treatment are crucial to preventing limb loss and improving outcomes in infections.

AREAS COVERED

This narrative review addresses the management of all DFIs, including the approach to clinical evaluation, appropriate diagnostic methods, and optimal therapeutic strategies. We specifically address key areas in antibiotic therapy, and surgical interventions and techniques. Based on our literature review and extensive, multidisciplinary experience, we developed a novel treatment flowchart specifically for the management of DFO.

EXPERT OPINION

Managing DFIs, including DFO, requires a multidisciplinary approach tailored to each patient's clinical presentation. While antibiotics, surgery, and wound care each play a crucial role, the decision-making process should always consider the infection's severity and chronicity. Our proposed flowchart for DFO management emphasizes the importance of logically-sequenced, easy to apply and tailored interventions to prevent unnecessary amputations and improve outcomes. Further research is needed to further refine this flowchart in clinical practice and demonstrate its effectiveness.

Harnessing Cyclic di-GMP Signaling: A Strategic Approach to Combat Bacterial Biofilm-Associated Chronic Infections

Cyclic dimeric guanosine monophosphate (c-di-GMP) plays a vital role within the nucleotide signaling network of bacteria, participating in various biological processes such as biofilm formation and toxin production, among others. Substantial evidence demonstrates its critical involvement in the progression of chronic infections. Treating chronic infections seems critical, and there is a worldwide quest for drugs that target pathogens' unique and complex virulence-associated signaling networks. c-di-GMP is a promising therapeutic target by serving as a distinct virulence factor, solving problems associated with drug resistance, biofilm dispersion, and its related septicemia complications. c-di-GMP levels act as checkpoints for several biofilm-associated molecular pathways, viz., Gac/Rsm, BrlR, and SagS signaling systems. C-di-GMP is also engaged in the Wsp chemosensory pathway responsible for rugose small colony variants observed in cystic fibrosis-related lung infections. Considering all factors, c-di-GMP serves as a pivotal hub in the intricate cascade of biofilm regulation. By overseeing QS systems, exopolysaccharide synthesis, and antibiotic resistance pathways in chronic infections, it emerges as a linchpin for effective drug development strategies against biofilm-related ailments. This underscores the significance of understanding the multifaceted signaling networks. c-di-GMP's role is highlighted in this review as a concealed virulence component in various bacterial pathogens, suggesting that medications targeting it could hold promise in treating chronic disorders associated with biofilms.

Revisiting Antibiotic-Impregnated Cement Spacer for Diabetic Osteomyelitis of the Foot

INTRODUCTION

Despite the rising global awareness and improvement of socioeconomic and living standards, the prevalence of diabetic osteomyelitis (DOM) and its complications has been increasing rapidly. This study aims to investigate the long-term prognosis of DOM of the foot treated using antibiotic-impregnated cement spacer (ACS) and the contributing risk factors for reoperation.

METHODS AND MATERIALS

We retrospectively reviewed the data of 55 diabetic patients with Meggitt-Wagner Grade IIB wounds diagnosed with osteomyelitis of the foot, treated in our institution with excessive debridement, excision of the infected tissue, and implantation of antibiotic-impregnated cement spacer fixed with a Kirschner wire. Descriptive statistics, including patient demographics, were analyzed. Statistical analysis was performed using point-biserial correlation and a Chi-square test with Cramer's V effect-size estimation to determine the relationship between reoperation and various parameters.

RESULTS

55 patients (36 (65.45%) males and 19 (34.55%) females) with a median age of 64 (39-84) years were thoroughly analyzed throughout a median follow-up of 884 days (2-4671 days). Of the entire cohort, 29 (52.72%) patients achieved primary successful infection eradication without any further intervention, and 8 (14.54%) patients were successfully treated using a secondary procedure. More than half of the reoperated patients underwent the secondary intervention within less than a month after the primary ACS. When assessing correlation, age (r = 0.28, p = 0.04), gender (r = 0.31, p = 0.02), Staphylococcus aureus (r = -0.10, p = 0.04), and the use of gentamicin-only antibiotic cement spacer (r = 0.34, p = 0.01) demonstrated statistically significant correlation to reoperation. 89.18% of the patients who achieved infection eradication did not undergo cement removal.

CONCLUSIONS

ACS has shown excellent results in eradicating bone infection with up to 7.23 years of follow-up, acting as a structural stabilizer, preventing soft tissue contractures, and delivering highly concentrated local antibiotic treatment both to soft tissue and bone. Regardless, specific factors should be thoroughly evaluated prior to surgery, as advancing age, gender, and the use of gentamicin-only antibiotics appear to be positively associated with a higher likelihood of reoperation. Conversely, infections caused by cultured Staphylococcus aureus seem to be inversely related to reoperation.

On-demand Opto-Laser activatable nanoSilver ThermoGel for treatment of full-thickness diabetic wound in a mouse model

Patients suffering from diabetes mellitus are prone to develop diabetic wounds that are non-treatable with conventional therapies. Hence, there is an urgent need of hour to develop the therapy that will overcome the lacunas of conventional therapies. This investigation reports the Quality by Design-guided one-pot green synthesis of unique Opto-Laser activatable nanoSilver ThermoGel (OL→nSil-ThermoGel) for hyperthermia-assisted treatment of full-thickness diabetic wounds in mice models. The characterization findings confirmed the formation of spherical-shaped nanometric Opto-Laser activatable nanoSilver (30.75 ± 2.7 nm; ∆T: 37 ± 0.2 °C → 66.2 ± 0.1 °C; at 1.8 W/cm2 NIR laser density). The findings indicated acceptable in vitro cytocompatibility and significant keratinocyte migration (95.04 ± 0.07 %) activity of OL→nSil towards HaCaT cells. The rheological data of OL→nSil hybridized in situ thermoresponsive gel (OL→nSil-ThermoGel) showed the gelling temperature at 32 ± 2 °C. In vivo studies on full-thickness diabetic wounds in a Mouse model showed OL→nSil-ThermoGel accelerated wound closure (94.42 ± 1.03 %) and increased collagen synthesis, angiogenesis, and decreased inflammatory markers. Similarly, immunohistochemistry study showed significant angiogenesis and faster phenotypic switching of fibroblasts to myofibroblasts in OL→nSil-ThermoGel treated diabetic wounds. Histological evaluation revealed a marked rise in keratinocyte migration, organized collagen deposition, and early regeneration of the epithelial layer compared to the diabetic wound control. In conclusion, the OL→nSil-ThermoGel modulates the cytokines, re-epithelialization, protein expression, and growth factors, thereby improving the repair and regeneration of diabetic wounds in mice.

The Role of Autologous Platelet Concentrates as a Local Antibiotic Delivery System: A Systematic Scoping Review

OBJECTIVES

Ongoing research has begun to develop innovative approaches to deliver local antibiotics while minimizing systemic side effects, antimicrobial resistance, and limited tissue penetration. Autologous platelet concentrates (APCs) offer promise in delivering antibiotics directly to infection sites. Despite the interest, a comprehensive evaluation of their effectiveness is lacking. Therefore, this systematic scoping review aims to collect and appraise studies regarding the efficacy of APCs in delivering antibiotics.

METHODS

A systematic electronic search of PubMed, Scopus, and Web of Science, using a combination of keywords, was conducted up to February 2024. Articles addressing the use of APCs as a local antibiotic delivery system were included.

RESULTS

A total of 13 articles, including 10 in vitro studies, 1 in vitro and clinical study, 1 ex vivo study, and 1 clinical study, were selected. Antibiotic loading capacity and release was confirmed in all studies using doxycycline, gentamicin, linezolid, vancomycin, metronidazole, and penicillin. In addition, the antibacterial effect was obtained mainly against E. coli., P. aeruginosa, S. mitis, H. influenzae, S. pneumoniae, and S. aureus.

CONCLUSIONS

The incorporation of antibiotics into APCs has been proven to facilitate the effective release of antimicrobial agents at optimal concentrations, potentially reducing the incidence of post-operative infections, substituting, or augmenting systemic antibiotic treatment while retaining APCs' inherent healing properties.

Advances in nucleic acid delivery strategies for diabetic wound therapy

In recent years, the prevalence of diabetic wounds has significantly increased, posing a substantial medical challenge due to their propensity for infection and delayed healing. These wounds not only increase mortality rates but also lead to amputations and severe mobility issues. To address this, advancements in bioactive molecules such as genes, growth factors, proteins, peptides, stem cells, and exosomes into targeted gene therapies have emerged as a preferred strategy among researchers. Additionally, the integration of photothermal therapy (PTT), nucleic acid, and gene therapy, along with 3D printing technology and the layer-by-layer (LBL) self-assembly approach, shows promise in diabetic wound treatment. Effective delivery of small interfering RNA (siRNA) relies on gene vectors. This review provides an in-depth exploration of the pathophysiological characteristics observed in diabetic wounds, encompassing diminished angiogenesis, heightened levels of reactive oxygen species, and impaired immune function. It further examines advancements in nucleic acid delivery, targeted gene therapy, advanced drug delivery systems, layer-by-layer (LBL) techniques, negative pressure wound therapy (NPWT), 3D printing, hyperbaric oxygen therapy, and ongoing clinical trials. Through the integration of recent research insights, this review presents innovative strategies aimed at augmenting the multifaceted management of diabetic wounds, thus paving the way for enhanced therapeutic outcomes in the future.

Porous silicon-based sensing and delivery platforms for wound management applications

Wound management remains a great challenge for clinicians due to the complex physiological process of wound healing. Porous silicon (PSi) with controlled pore morphology, abundant surface chemistry, unique photonic properties, good biocompatibility, easy biodegradation and potential bioactivity represent an exciting class of materials for various biomedical applications. In this review, we focus on the recent progress of PSi in the design of advanced sensing and delivery systems for wound management applications. Firstly, we comprehensively introduce the common type, normal healing process, delaying factors and therapeutic drugs of wound healing. Subsequently, the typical fabrication, functionalization and key characteristics of PSi have been summarized because they provide the basis for further use as biosensing and delivery materials in wound management. Depending on these properties, the rise of PSi materials is evidenced by the examples in literature in recent years, which has emphasized the robust potential of PSi for wound monitoring, treatment and theranostics. Finally, challenges and opportunities for the future development of PSi-based sensors and delivery systems for wound management applications are proposed and summarized. We hope that this review will help readers to better understand current achievements and future prospects on PSi-based sensing and delivery systems for advanced wound management.

Variation in Systemic Antibiotic Treatment for Diabetic Foot Osteomyelitis in England and Wales: A Multi-Centre Case Review

Background: Diabetic foot osteomyelitis (DFO) is a major complication and can lead to significant morbidity and mortality. Systemic antibiotic therapy is often initiated first line to achieve quiescence of infection. To perform a multi-centre case review of systemic antibiotic intervention to treat adults with DFO in England and Wales and compare with national guidelines 'Diabetic foot problems: prevention and management'. Methods: Eight centres from England and Wales retrospectively collated data from a minimum of five adults (aged ≥ 18 years) from electronic case records. All patients were treated with systemic antibiotics following a new diagnosis of DFO (1 June 2021-31 December 2021). Results: 40 patients (35 males and 5 females) were included; the mean age was 62.3 years (standard deviation (SD) 13.0). Patients commenced systemic oral 14 (35%) or intravenous 26 (65%) antibiotic therapy following a new diagnosis of DFO. Twenty-seven (67.5%) patients were medically or surgically managed in the 12-week period with clinical quiescence of infection. Twenty-one patients (52.5%) had no recurrence of DFO infection within 12 weeks; seventeen (42.5%) of these patients had clinical quiescence of infection with systemic antibiotics alone without surgical intervention and nine (22.5%) of these cases had no recurrence of DFO. There were no cases of major amputation or death. All centres showed significant in-centre variability in systemic antibiotic management; variability was reported in the clinical and quantity indicators specifically to antibiotic selection, single versus dual therapy, mode of delivery and duration of treatment. Conclusions: This case review identifies there is existing variation when treating adults with systemic antibiotics for DFO. Further national guidance is required to standardise service delivery and care to improve patient outcomes.

Brazilian Society of Angiology and Vascular Surgery 2023 guidelines on the diabetic foot

The diabetic foot interacts with anatomical, vascular, and neurological factors that challenge clinical practice. This study aimed to compile the primary scientific evidence based on a review of the main guidelines, in addition to articles published on the Embase, Lilacs, and PubMed platforms. The European Society of Cardiology system was used to develop recommendation classes and levels of evidence. The themes were divided into six chapters (Chapter 1 - Prevention of foot ulcers in people with diabetes; Chapter 2 - Pressure relief from foot ulcers in people with diabetes; Chapter 3 -Classifications of diabetic foot ulcers; Chapter 4 - Foot and peripheral artery disease; Chapter 5 - Infection and the diabetic foot; Chapter 6 - Charcot's neuroarthropathy). This version of the Diabetic Foot Guidelines presents essential recommendations for the prevention, diagnosis, treatment, and follow-up of patients with diabetic foot, offering an objective guide for medical practice.

An Orthopedic Perspective on Diabetic Foot Attack - A Case Report

Introduction

Diabetic foot attack (DFA), also known as diabetic foot ulceration, is a severe and potentially limb-threatening complication of diabetes mellitus. It refers to the development of open sores or ulcers on the feet of individuals with diabetes, often leading to infections, tissue damage, and, in extreme cases, amputation. The underlying cause of DFAs is multifactorial and involves a complex interplay of various factors, including peripheral neuropathy, peripheral arterial disease, foot deformities, impaired wound healing, and poor glycemic control. This case report would be first of its kind from an orthopedic perspective.

Case Report

A 55-year-old white British gentleman, a chronic uncontrolled Type 2 diabetic, was referred by the medical team on a busy on-call night. He presented with a sudden onset pain, swelling, and difficulty in weight bearing on his left foot. He had a non-healing plantar ulcer for over a year. His inflammatory markers were abnormally high and magnetic resonance imaging of his leg and foot showed massive collection in his foot with gas extending along the posterior compartment. Diagnosis of a severe DFA was made, and urgent debridement and washout were carried out. Despite aggressive debridement, patient progressively deteriorated warranting an admission into intensive care unit. After subsequent debridement and local antibiotic therapy, he recovered and was discharged with clinic follow-up.

Conclusion

Effective management strategies for DFAs encompass a multidisciplinary approach. Preventive measures play a key role in reducing the incidence of DFAs. Regular foot examinations, self-care education, proper glycemic control, and foot hygiene are essential components of preventive strategies. Patient education regarding self-monitoring, appropriate footwear, and early recognition of foot-related complications is crucial to empower individuals with diabetes to take proactive measures.

Investigation and management of diabetic foot osteomyelitis: An update for the foot and ankle orthopaedic surgeon

Diabetic foot osteomyelitis (DFO) poses a significant challenge in the management of diabetic patients, often leading to severe complications and increased morbidity. Effective management of DFO requires a multidisciplinary approach, involving endocrinologists, infectious disease specialists, vascular surgeons, orthopaedic surgeons, and wound care experts. Early diagnosis is paramount, facilitated by advanced imaging techniques such as magnetic resonance imaging (MRI) and bone scintigraphy. Once diagnosed, the treatment strategy hinges on a combination of medical and surgical interventions. Antibiotic therapy, guided by culture results, plays a central role in managing DFO. Tailored regimens targeting the specific pathogens involved are administered, often for prolonged durations. Surgical intervention becomes necessary when conservative measures fall short. Surgical approaches range from minimally invasive procedures, like percutaneous drainage, to more extensive interventions like debridement and bone resection. Prevention of DFO recurrence is equally vital, emphasising glycemic control, meticulous foot care, patient education, monitoring of at-risk signs, revascularization and early intervention when indicated. The management of diabetic foot osteomyelitis mandates a comprehensive strategy that addresses both the infectious and surgical aspects of the condition. A collaborative, interdisciplinary approach ensures timely diagnosis, tailored treatment, and holistic care. Further research into novel therapeutic modalities and long-term outcomes remains essential in refining the management of this complex and debilitating complication of diabetes.

Examining the effect of polyurethane dressing containing silver particles on the rate of diabetic foot ulcer infection in hospitalized patients: A randomized control study

Background and Aims

One of the new types of dressings is the polyurethane dressing containing silver particles. This study was designed to evaluate the effect of polyurethane dressing containing silver particles on the rate of diabetic foot ulcer infection in hospitalized patients in a military hospital.

Methods

This was a randomized clinical trial study on 48 patients with diabetic foot ulcers who were referred to the wound clinic of Shahid Dr. Chamran Hospital in 2022. The qualified samples were divided into two groups of silver polyurethane dressing and simple sterile dressing based on a randomization block method. The wounds of both groups of patients were initially cleaned with normal saline and in the first round of dressing, and a sample of tissue secretions was collected by the researcher using a sterile swab from the wounds of the patients on two occasions, superficially and deeply. The patients' wounds in the intervention group were dressed with polyurethane foam dressing containing silver particles, while the simple sterile routine dressing was used in the control group. The rate of infection and wound secretions were examined and recorded on the first, seventh, fourteenth, and twenty-first days from the start of dressing in both groups. To collect data, the IDSA tool was used.

Results

The rates of wound infection before the intervention showed no significant differences in the two groups (p = 0.242). However, these rates changed on the 7th, 14th, and 21st days after the intervention. Moreover, the infection rate was significantly lower in the polyurethane dressing group containing silver particles (p < 0.001 and F = 30.31).

Conclusions

Using polyurethane dressing was proven to be more effective in this study on the rate of diabetic ulcer infection in patients compared to the simple sterile dressing. Thus, nurses can use this dressing for faster treatment of diabetic foot ulcers infection.

Predictive value of systemic immune inflammation index (SII) and prognostic nutritional index (PNI) on mortality after below-knee amputation

This retrospective cross-sectional study aimed to evaluate the predictive value of SII (Systemic Immune Inflammation Index) and PNI (Prognostic Nutritional Index) with blood ratios on mortality in diabetic foot patients who underwent below-knee amputation. A total of 231 living (n = 71; 30.7%) and exitus (n = 160; 69.3%) patients were evaluated. The mortality group was divided into 3 groups: 30-day mortality (n = 62; 38.8%), 1-year mortality (n = 62; 38.8%), and over-1-year mortality (n = 36; 22.5%). The hemogram, SII, and PNI parameters of the patients were evaluated. Age, some blood count parameters and SII were significantly higher in the exitus group (P < .05). The lymphocyte, monocyte, eosinophil, albumin, and PNI levels were significantly higher in the living group (P < .05). Mortality was significantly predicted by age (B [regression coefficient] = 0.026, P < .05), NLR (neutrophil lymphocyte ratio) (B = -0.065, P < .05), PNI (B = -0.100, P < .01), and SII (B = 0.00000024, P < .01). The predictive values of CAR (C reactive protein albumin ratio), PNI, and SII were 77.3%, 77.0%, and 76.1%, respectively. For CAR of 30.88 cutoff value, the sensitivity and specificity were 79.4% and 64.8%, respectively. For the PNI 22.0143 cutoff value, the sensitivity and specificity were 66.9% and 5.6%, respectively. For the SII 732249.2481 cutoff value, the sensitivity and specificity were 91.9% and 31.0%, respectively. The predictive value of the PNI was significant for mortality time (B = 0.058; P < .01). The predictive value of PNI for 30-day mortality was significant (AUC (area under curve):0.632; P < .01), whereas its predictive value for 1-year mortality and over-1-year mortality after below-knee amputation was statistically insignificant (P > .05). Both the SII and PNI may be evaluated and used to predict mortality after below-knee amputation. The SII had a significant predictive value for 30-day mortality after below-knee amputation.

Timing of Revascularization and Parenteral Antibiotic Treatment Associated with Therapeutic Failures in Ischemic Diabetic Foot Infections

For ischemic diabetic foot infections (DFIs), revascularization ideally occurs before surgery, while a parenteral antibiotic treatment could be more efficacious than oral agents. In our tertiary center, we investigated the effects of the sequence between revascularization and surgery (emphasizing the perioperative period of 2 weeks before and after surgery), and the influence of administering parenteral antibiotic therapy on the outcomes of DFIs. Among 838 ischemic DFIs with moderate-to-severe symptomatic peripheral arterial disease, we revascularized 608 (72%; 562 angioplasties, 62 vascular surgeries) and surgically debrided all. The median length of postsurgical antibiotic therapy was 21 days (given parenterally for the initial 7 days). The median time delay between revascularization and debridement surgery was 7 days. During the long-term follow-up, treatment failed and required reoperation in 182 DFI episodes (30%). By multivariate Cox regression analyses, neither a delay between surgery and angioplasty (hazard ratio 1.0, 95% confidence interval 1.0–1.0), nor the postsurgical sequence of angioplasty (HR 0.9, 95% CI 0.5–1.8), nor long-duration parenteral antibiotic therapy (HR 1.0, 95% CI 0.9–1.1) prevented failures. Our results might indicate the feasibility of a more practical approach to ischemic DFIs in terms of timing of vascularization and more oral antibiotic use.

Clinical and Bacteriological Analyses of Biofilm-Forming Staphylococci Isolated from Diabetic Foot Ulcers

Background

Diabetes mellitus is a chronic disease that is associated with increased morbidity and mortality. Unfortunately, foot ulcers and amputations due to diabetes are very common in developing countries. The purpose of this study was to characterize the clinical presentation of diabetic foot ulcer (DFU) infections, isolate the causative agent, and analyze the biofilm formation and distribution of biofilm-related genes among isolated Staphylococci.

Material and Methods

The study included 100 diabetic patients suffering from DFUs attending Assiut University Hospital. Swabs were collected and antimicrobial susceptibility testing of the isolates was performed. Biofilm formation was tested phenotypically among staphylococcal isolates and the frequency of different biofilm genes was analyzed by PCR. Clinical presentations of diabetic foot ulcers were correlated with bacterial genetic characteristics. Spa types were determined using DNA Gear-a software.

Results

Microbiological analysis showed that 94/100 of the DFUs were positive for bacterial growth. The majority of infections were polymicrobial (54%, n=54/100). Staphylococci were the most commonly detected organisms, of which S. aureus represented 37.5% (n=24/64), S. haemolyticus 23.4% (n=15/64), S. epidermidis 34.3% (n=22/64) and other CNS 4.7% (n=3/64). Interestingly, co-infection with more than one species of Staphylococci was observed in 17.1% (n=11/64) of samples. A high level of antibiotic resistance was observed, where 78.1% (n=50/64) of Staphylococci spp were multidrug-resistant (MDR). Phenotypic detection showed that all isolated Staphylococci were biofilm-formers with different grades. Analysis of biofilm-forming genes among Staphylococci showed that the most predominant genes were icaD, spa, and bap. Isolates with a higher number of biofilm-related genes were associated with strong biofilm formation. Sequencing of the spa gene in S. aureus showed that our isolates represent a collection of 17 different spa types.

Conclusion

The majority of DFUs in our hospital are polymicrobial. Staphylococci other than S.aureus are major contributors to infected DFUs. MDR and biofilm formation are marked among isolates, which is paralleled by the presence of different categories of virulence-related genes. All severely infected wounds were associated with either strong or intermediate biofilm formers. The severity of DFU is directly related to the number of biofilm genes.