Diagnosis and Treatment of Diabetic Foot Infections

Diagnostic imaging of the diabetic foot: an EANM evidence-based guidance

PURPOSE

Consensus on the choice of the most accurate imaging strategy in diabetic foot infective and non-infective complications is still lacking. This document provides evidence-based recommendations, aiming at defining which imaging modality should be preferred in different clinical settings.

METHODS

This working group includes 8 nuclear medicine physicians appointed by the European Association of Nuclear Medicine (EANM), 3 radiologists and 3 clinicians (one diabetologist, one podiatrist and one infectious diseases specialist) selected for their expertise in diabetic foot. The latter members formulated some clinical questions that are not completely covered by current guidelines. These questions were converted into statements and addressed through a systematic analysis of available literature by using the PICO (Population/Problem-Intervention/Indicator-Comparator-Outcome) strategy. Each consensus statement was scored for level of evidence and for recommendation grade, according to the Oxford Centre for Evidence-Based Medicine (OCEBM) criteria.

RESULTS

Nine clinical questions were formulated by clinicians and used to provide 7 evidence-based recommendations: (1) A patient with a positive probe-to-bone test, positive plain X-rays and elevated ESR should be treated for presumptive osteomyelitis (OM). (2) Advanced imaging with MRI and WBC scintigraphy, or [18F]FDG PET/CT, should be considered when it is needed to better evaluate the location, extent or severity of the infection, in order to plan more tailored treatment. (3) In a patient with suspected OM, positive PTB test but negative plain X-rays, advanced imaging with MRI or WBC scintigraphy + SPECT/CT, or with [18F]FDG PET/CT, is needed to accurately assess the extent of the infection. (4) There are no evidence-based data to definitively prefer one imaging modality over the others for detecting OM or STI in fore- mid- and hind-foot. MRI is generally the first advanced imaging modality to be performed. In case of equivocal results, radiolabelled WBC imaging or [18F]FDG PET/CT should be used to detect OM or STI. (5) MRI is the method of choice for diagnosing or excluding Charcot neuro-osteoarthropathy; [18F]FDG PET/CT can be used as an alternative. (6) If assessing whether a patient with a Charcot foot has a superimposed infection, however, WBC scintigraphy may be more accurate than [18F]FDG PET/CT in differentiating OM from Charcot arthropathy. (7) Whenever possible, microbiological or histological assessment should be performed to confirm the diagnosis. (8) Consider appealing to an additional imaging modality in a patient with persisting clinical suspicion of infection, but negative imaging.

CONCLUSION

These practical recommendations highlight, and should assist clinicians in understanding, the role of imaging in the diagnostic workup of diabetic foot complications.

Clinical and Microbiological Profile of Diabetic Foot Ulcers Infected With Staphylococcus aureus in a Regional General Hospital in Bahia, Brazil

It is necessary to know the resistance profile of Staphylococcus aureus to better control diabetic foot ulcer infections, to establish rational antibiotic therapy, and to avoid the development of resistant strains. This cross-sectional study evaluated the clinical parameters, virulence, and antimicrobial resistance profiles of S aureus in patients with diabetic foot disease admitted to a public hospital. S aureus strains were identified in patients with diabetes with amputation indication. Infected tissue samples were collected, microbes were isolated and identified. The microbial resistance profile was determined. Samples were also analyzed for biofilm formation and other virulence markers. The 34 individuals examined were mostly men, black, aged 60 years on average, and generally had a low income and education level. Most individuals had type 2 diabetes, and the mean time since diagnosis was 13.9 years. On an SF-36 (the Medical Outcomes Study 36-item short-form health survey) quality-of-life questionnaire, 75% of individuals obtained a score equal to 0 for physical impairment. S aureus specimens from 17 patients were isolated, corresponding to 50% of samples. Five isolates were classified as methicillin-resistant S aureus (MRSA). Molecular typing revealed that 20% of MRSA strains were SCCmec type V and 80% were type I. All isolates were sensitive to doxycycline; 61.5% were resistant to erythromycin, 38.5% to cefoxitin, 30.7% to clindamycin and ciprofloxacin, 23% to meropenem, 15.3% to gentamicin, 38.5% to oxacillin, and 7.7% (one strain) to vancomycin. Regarding biofilm production, 53% of samples were able to produce biofilms, and 84.6% had icaA and/or icaD genes. Additionally, the following enterotoxin genes were identified in the isolates: seb, sec, seg, and sei (5.9%, 5.9%, 11.8%, and 23.9%, respectively) and agr types 1 (5.9%) and 2 (11.8%). Genotypic evaluation made it possible to understand the pathogenicity of S aureus strains isolated from the diabetic foot; laboratory tests can assist in the monitoring of patients with systemic involvement.

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.

Janus liposozyme for the modulation of redox and immune homeostasis in infected diabetic wounds

Diabetic foot ulcers often become infected, leading to treatment complications and increased risk of loss of limb. Therapeutics to manage infection and simultaneously promote healing are needed. Here we report on the development of a Janus liposozyme that treats infections and promotes wound closure and re-epithelialization. The Janus liposozyme consists of liposome-like selenoenzymes for reactive oxygen species (ROS) scavenging to restore tissue redox and immune homeostasis. The liposozymes are used to encapsulate photosensitizers for photodynamic therapy of infections. We demonstrate application in methicillin-resistant Staphylococcus aureus-infected diabetic wounds showing high ROS levels for antibacterial function from the photosensitizer and nanozyme ROS scavenging from the liposozyme to restore redox and immune homeostasis. We demonstrate that the liposozyme can directly regulate macrophage polarization and induce a pro-regenerative response. By employing single-cell RNA sequencing, T cell-deficient Rag1-/- mice and skin-infiltrated immune cell analysis, we further reveal that IL-17-producing γδ T cells are critical for mediating M1/M2 macrophage transition. Manipulating the local immune homeostasis using the liposozyme is shown to be effective for skin wound repair and tissue regeneration in mice and mini pigs.

Biomaterials-Based Strategies to Enhance Angiogenesis in Diabetic Wound Healing

Amidst the present healthcare issues, diabetes is unique as an emerging class of affliction with chronicity in a majority of the population. To check and control its effects, there have been huge turnover and constant development of management strategies, and though a bigger part of the health care area is involved in achieving its control and the related issues such as the effect of diabetes on wound healing and care and many of the works have reached certain successful outcomes, still there is a huge lack in managing it, with maximum effect yet to be attained. Studying pathophysiology and involvement of various treatment options, such as tissue engineering, application of hydrogels, drug delivery methods, and enhancing angiogenesis, are at constantly developing stages either direct or indirect. In this review, we have gathered a wide field of information and different new therapeutic methods and targets for the scientific community, paving the way toward more settled ideas and research advances to cure diabetic wounds and manage their outcomes.

Hydrogels for Local and Sustained Delivery of Bacteriophages to Treat Multidrug-Resistant Wound Infections

Bacteriophages (phages), viruses that specifically target and kill bacteria, represent a promising strategy to combat multidrug-resistant (MDR) pathogens such as Pseudomonas aeruginosa (Pa). However, delivering sufficient concentrations of active phages directly to the infection site remains challenging, with current methods having variable success. Here we present "HydroPhage", an innovative hydrogel system for the sustained release of high-titer phages to effectively treat infections caused by MDR pathogens. Our injectable hydrogels, featuring dual-crosslinking of hyaluronic acid and PEG-based hydrogels through static covalent thioether bonds and dynamic covalent hemithioacetal crosslinks (DCC), encapsulate phages at concentration up to 1011 PFU/mL, and achieves controlled release of 109 PFU daily over a week, surpassing levels of current clinical dosages, with more than 60% total phage recovery. In a preclinical mouse model of extended wound infection, compared to intravenous treatment, we demonstrate enhanced bacterial clearance by localized, high-dose, and repeated phage dosing despite the emergence of bacterial resistance to phages. This work advances the development of clinically practical wound dressings tailored for resistant infections.

IWGDF/IDSA guidelines on the diagnosis and treatment of diabetes-related foot infections (IWGDF/IDSA 2023)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

Treatment of clinically uninfected diabetic foot ulcers, with and without antibiotics

OBJECTIVE

Current guidelines do not recommend the use of antibiotics to treat clinically uninfected ulcers. However, physicians continue to prescribe antibiotics for clinically uninfected ulcers with the rationale 'better to be safe than sorry'. Yet, antibiotic resistance is increasing, side-effects are common and treatment costs are rising. Evidence is needed to identify whether antibiotic treatment for clinically uninfected ulcers can be justified or we should stop prescribing them. The aim of this study was to evaluate whether antibiotic treatment in cases of clinically uninfected ulcers improved ulcer healing compared to treatment without antibiotics.

METHOD

Consecutive patients treated in the outpatient clinic for clinically uninfected diabetic foot ulcer both in 2015 and in 2017 were retrospectively analysed. Primary outcome was ulcer healing at one year. Secondary outcomes were limb salvage, freedom from any amputation, amputation-free survival (AFS) and survival.

RESULTS

A total of 102 ulcers of 91 patients were included for final analyses. The non-antibiotics and antibiotics groups both consisted of 51 ulcers. Ulcer healing at one year was 77.3% in the non-antibiotics group and 74.7% in the antibiotics group (p=0.158). No difference was found for limb salvage (93.8% versus 95.9%, respectively; p=0.661), freedom from any amputation (85.6% versus 85.6%, respectively; p=1.000), AFS (85.4% versus 79.1%, respectively; p=0.460) or survival (89.6% versus 83.7%, respectively; p=0.426).

CONCLUSION

In this study, no benefits of antibiotic treatment over non-antibiotic treatment for clinically uninfected ulcers were identified. The findings of this study emphasise the recommendation of current guidelines to not treat clinically uninfected ulcer with antibiotics.

Prevalence of S. aureus and/or MRSA in hospitalized patients with diabetic foot and establishment of LAMP methods for rapid detection of the SCCmec gene

BACKGROUND

Patients with diabetic feet are prone to be infected due to the impaired immune system. However, the prognostic outcome of different microbial infections remains controversial. Identification and rapid screening of the pathogenic microorganisms that pose the greatest threat to the prognosis of patients with diabetic foot infections (DFIs) is critical.

METHODS

Clinical data were statistically analyzed, which were obtained from 522 patients with DFIs, including pathogenic bacterial culture results and treatment outcomes at the last return visit. In addition, a loop-mediated isothermal amplification (LAMP) detection method was developed to identify the prevalent subtype of methicillin-resistant Staphylococcus aureus (MRSA) in DFIs patients. This study was approved by the Ethics Committee of Nanfang Hospital (NFEC-202012-K6) and registered on ClinicalTrials.gov (NCT04916457) on June 1, 2021.

RESULTS

We found that the proportion of patients with infections of Staphylococcus aureus (S. aureus) and MRSA was 27.7% (145/522) and 33.7% (49/145), respectively. Additionally, the incidence of osteomyelitis was 46.9% (23/49) and amputation/disability was 40.8% (20/49) in patients with MRSA infection, which were significantly higher compared to patients with other types of bacterial infections such as methicillin-susceptible Staphylococcus aureus (MSSA). Notably, we demonstrated that the main prevalent subtype of MRSA in DFIs patients in our hospital was Staphylococcal chromosomal cassettes mec (SCCmec) type II. In addition, it only takes 1.5 h to complete the entire experimental procedure in this LAMP assay, providing high sensitivity (100%) and specificity (77.8%) in hospitalized patients with DFIs.

CONCLUSIONS

We demonstrated there is a very high rate of MRSA isolation in patients with DFIs and revealed that patients infected with MRSA are at a higher risk of developing osteomyelitis, and amputation or disability. Importantly, we have developed a method for quickly screening newly admitted patients for MRSA.

Underlying Mechanism of Traditional Herbal Formula Chuang-Ling-Ye in the Treatment of Diabetic Foot Ulcer through Network Pharmacology and Molecular Docking

BACKGROUND

Chuang-Ling-Ye (CLY) has been clinically proven to be an effective Chinese medicine for the treatment of diabetic foot ulcers (DFU).

OBJECTIVES

This study aimed to investigate the possible mechanism of CLY in relation to DFU using network pharmacology and molecular docking.

MATERIALS AND METHODS

Firstly, relevant targets of CLY against DFU were obtained from TCMSP, Swiss Target Prediction database and GEO database. Then, topological analysis was employed by Cytoscape to screen the top 6 core active ingredients and the top 8 hub targets. Furthermore, the OmicShare Tools were applied for gene ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment analysis. Finally, the results of network pharmacology were verified by molecular docking method.

RESULTS

CLY has 61 active compounds and 361 targets after de-duplication, and the top 8 hub targets were EGFR, TP53, CCND1, IL-1B, CREBBP, AR, PTGS2 and PGR. GO enrichment analysis is mainly related to signal transducer activity, receptor activity, and molecular transducer activity. KEGG pathway analysis indicated that these shared targets were primarily focused on AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, IL-17 signaling pathway, and JAK-STAT signaling pathway. Molecular docking results showed that physciondiglucoside, 2-cinnamoyl-glucose and kinobeon A were well bound with EGFR, IL-1B, AR and PTGS2.

CONCLUSION

This study demonstrated that CLY has anti-oxidative stress and anti-inflammatory effects in the treatment of DFU through various constituents, multiple targets, and multiple pathways, which provides a valuable point of reference for future investigations on CLY.

GATR-3, a Peptide That Eradicates Preformed Biofilms of Multidrug-Resistant Acinetobacter baumannii

Acinetobacter baumannii is a gram-negative bacterium that causes hospital-acquired and opportunistic infections, resulting in pneumonia, sepsis, and severe wound infections that can be difficult to treat due to antimicrobial resistance and the formation of biofilms. There is an urgent need to develop novel antimicrobials to tackle the rapid increase in antimicrobial resistance, and antimicrobial peptides (AMPs) represent an additional class of potential agents with direct antimicrobial and/or host-defense activating activities. In this study, we present GATR-3, a synthetic, designed AMP that was modified from a cryptic peptide discovered in American alligator, as our lead peptide to target multidrug-resistant (MDR) A. baumannii. Antimicrobial susceptibility testing and antibiofilm assays were performed to assess GATR-3 against a panel of 8 MDR A. baumannii strains, including AB5075 and some clinical strains. The GATR-3 mechanism of action was determined to be via loss of membrane integrity as measured by DiSC3(5) and ethidium bromide assays. GATR-3 exhibited potent antimicrobial activity against all tested multidrug-resistant A. baumannii strains with rapid killing. Biofilms are difficult to treat and eradicate. Excitingly, GATR-3 inhibited biofilm formation and, more importantly, eradicated preformed biofilms of MDR A. baumannii AB5075, as evidenced by MBEC assays and scanning electron micrographs. GATR3 did not induce resistance in MDR A. baumannii, unlike colistin. Additionally, the toxicity of GATR-3 was evaluated using human red blood cells, HepG2 cells, and waxworms using hemolysis and MTT assays. GATR-3 demonstrated little to no cytotoxicity against HepG2 and red blood cells, even at 100 μg/mL. GATR-3 injection showed little toxicity in the waxworm model, resulting in a 90% survival rate. The therapeutic index of GATR-3 was estimated (based on the HC50/MIC against human RBCs) to be 1250. Overall, GATR-3 is a promising candidate to advance to preclinical testing to potentially treat MDR A. baumannii infections.

Integrating Point-of-Care Bacterial Fluorescence Imaging-Guided Care with Continued Wound Measurement for Enhanced Wound Area Reduction Monitoring

AIM

This prospective observational study investigated wound area reduction (WAR) outcomes in a complex wound population composed of non-healing acute and chronic wounds. The relationship between bacterial autofluorescence signals and WAR was investigated. Area measurements were collected both manually and digitally, and both methods were compared for accuracy.

METHODS

Twenty-six participants with 27 wounds of varying etiologies were observed twice weekly for two weeks. Digital wound measurement, wound bacterial status assessment, and targeted debridement were performed through a point-of-care fluorescence imaging device (MolecuLight® i: X, MolecuLight Inc, Toronto, Canada). The wound area reduction (WAR) rate was calculated using baseline and last visit measurements. Statistical analyses, including t-tests, Fisher exact tests, the Wilcoxon signed rank test for method comparison, and ANOVA for bacterial subgroups, were applied as pertinent.

RESULTS

The overall average WAR was -3.80 cm2, or a decrease of 46.88% (manual measurement), and -2.62 cm2, or a 46.05% decrease (digital measurement via MolecuLight® device). There were no statistically significant differences between the WAR of acute and chronic wounds (p = 0.7877). A stepwise correlation between the WAR and bacterial status classification per fluorescence findings was observed, where persistent bacteria resulted in worse WAR outcomes. An overestimation of wound area by manual measurement was 23% on average.

CONCLUSION

Fluorescence imaging signals were linked to WAR outcome and could be considered predictive. Wounds exhibiting bacterial loads that persisted at the end of the study period had worse WAR outcomes, while those for which management was able to effectively remove them demonstrated greater WAR. Manual measurement of the wound area consistently overestimated wound size when compared to digital measurement. However, if performed by the same operator, the overestimation was uniform enough that the WAR was calculated to be close to accurate. Notwithstanding, single wound measurements are likely to result in overestimation.

Comorbid status in patients with osteomyelitis is associated with long-term incidence of extremity amputation

INTRODUCTION

Osteomyelitis is associated with significant morbidity, including amputation. There are limited data on long-term amputation rates following an osteomyelitis diagnosis. We sought to determine the incidence of amputation in patients with osteomyelitis over 2 years.

RESEARCH DESIGN AND METHODS

Observational cohort study of 1186 inpatients with osteomyelitis between 2004 and 2015 and stratified by osteomyelitis location status to evaluate the impact on amputation, mortality rates, readmission data, and inpatient days.

RESULTS

Persons with diabetes had 3.65 times greater probability of lower extremity amputation (p<0.001), readmission (p<0.001), and longer inpatient stay (p<0.001) and had higher 2-year mortality (relative risk (RR) 1.23, p=0.0027), adjusting for risk factors. Male gender (RR 1.57, p<0.001), black race (RR 1.41, p<0.05), former smoking status (RR 1.38, p<0.01), myocardial infarction (RR 1.72, p<0.001), congestive heart failure (RR 1.56, p<0.001), peripheral vascular disease (RR 2.25, p<0.001) and renal disease (RR 1.756, p<0.001) were independently associated with amputation. Male gender (RR 1.39, p<0.01), black race (RR 1.27, p<0.05), diabetes (RR 2.77, p<0.001) and peripheral vascular disease (RR 1.59, p<0.001) had increased risk of lower, not upper, extremity amputation.

CONCLUSIONS

Patients with osteomyelitis have higher rates of amputation and hospitalization. Clinicians must incorporate demographic and comorbid risk factors to protect against amputation.

Decision-making processes for non-emergency diabetes-related lower extremity amputations: A scoping review

Living with a diabetes-related foot ulcer has significant lifestyle impacts. Whilst often considered a last resort, amputation can overcome the burden of ulcer management, for an improved quality of life. However, limited research has been conducted to understand how the decision to amputate is made for people with a chronic ulcer when amputation is not required as a medical emergency. Therefore, the aim was to identify and map key concepts in the literature which describe the decision-making for diabetes-related amputations. This review followed Arksey and O'Malley's PRISMA scoping review framework. Five electronic databases and grey literature were searched for papers which described clinical reasoning and/or decision-making processes for diabetes-related amputation. Data were extracted and mapped to corresponding domains of the World Health Organisation's International Classification of functioning, Disability and Health (ICF) framework. Ninety-four papers were included. Personal factors including emotional wellbeing, quality of life, and treatment goals are key considerations for an elective amputation. It is important to consider an individual's lifestyle and personal circumstances, as well as the pathology when deciding between amputation or conservative management. This highlights the importance of a holistic and shared decision-making process for amputation which includes assessment of a person's lifestyle and function.

IWGDF/IDSA Guidelines on the Diagnosis and Treatment of Diabetes-related Foot Infections (IWGDF/IDSA 2023)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

Reduction in the prevalence of methicillin-resistant Staphylococcus aureus in tissue and wound swab samples taken from outpatients attending a specialist diabetic foot clinic 2005-2021

AIMS

To assess annual change in prevalence of methicillin resistant Staphylococcus aureus (MRSA) from tissue and wound swab samples from foot ulcers (DFUs) in people with diabetes between 2005 and 2021.

METHODS

A retrospective analysis of everyone with MRSA positive wound or tissue swabs taken from our specialist multidisciplinary foot clinic between July 2005 and July 2021.

RESULTS

A total of 406 MRSA positive isolates from DFU swabs were identified from 185 individuals attending the foot clinic. There were 22 hospital-acquired infections (HAIs) and 159 community-acquired infections (CAIs). Fifty-two per cent (n = 37) of these individuals from 2010 to 2021 (n = 71) had presence of at least three risk factors for MRSA. The total number of swabs sent was 6312 from 1916 individuals living with diabetes. Annual MRSA DFU prevalence peaked in 2008 at 14.6% (n = 38), decreased in 2013 to 5.2% (n = 20) and did not exceed 4% (n = 6) from 2015 to 2021. Hospital MRSA was lowest in 2021 (n = 211), a 76% fall from 2007 (n = 880). Incidence of MRSA HAI from 2015 to 2021 ranged from 5.4% (n = 14) in 2020 to 11.5% (n = 41) in 2018.

CONCLUSIONS

Prevalence of MRSA in DFU infections treated as outpatients is decreasing in line with falls in hospital acquired blood-borne infections and with overall hospital MRSA incidence. This is likely a reflection of the combination of interventions, including stringent antibiotic prescribing and decolonisation strategies. Reduction in prevalence should have positive impact on outcomes in people living with diabetes, reducing the complication of osteomyelitis and necessity for long-term antibiotic administration.

Arterial leg ulcers-Bacterial patterns, antimicrobial resistance and clinical characteristics, a retrospective single-centre cohort, 2012-2021

OBJECTIVE

Severe wound infections in patients with peripheral artery disease (PAD) are common, potentially life- and limb-threatening, and difficult to treat. Evidence on patients with infected leg ulcers in PAD is scarce. This study aims to provide insight into the microbiological patterns and antimicrobial resistance (AMR) of specific pathogens in patients with arterial leg ulcers.

METHODS AND DESIGN

In this retrospective, consecutive, single-centre study 16,553 patients underwent an endovascular revascularization procedure between 2012 and 2021. Of these, 1,142 patients had PAD Rutherford category 5 or 6 with infected leg ulcers. Logistic regression was used to identify risk factors for Staphylococcus aureus-associated infections.

RESULTS

A total of 3,431 bacterial isolates were detected, of which 2,335 (68.1%) bacterial isolates were gram-positive and 1,096 (31.9%) were gram-negative species. The most prevalent bacteria were S. aureus (18.6%), Enterococcus faecalis (9.1%) and S. epidermidis (7.8%). Pseudomonas aeruginosa (5.6%), Proteus mirabilis (3.7%) and Escherichia coli (3.4%). The resistance of S. aureus isolates to clindamycin was 11.0%. Resistance to oxacillin was rare (1.5%). P. aeruginosa is frequently resistant to ciprofloxacin (14.4%) whilst intrinsically resistant to trimethoprim/sulfamethoxazole. P. mirabilis and E. coli were frequently resistant to both ciprofloxacin (7.3; 20.7%) and trimethoprim/sulfamethoxazole (24.6; 22.6%), respectively. Resistance to amoxicillin/clavulanic acid was high among E. coli isolates (36.8%). Multi-drug resistance (MDR) was rare among S. aureus and P. aeruginosa isolates. In contrast, the proportion of MDR was high in E. coli isolates. End-stage renal disease was independently positively associated with S. aureus identification (p = .042).

CONCLUSION

S. aureus was the most common pathogen in arterial leg ulcers with end-stage renal disease being an independent risk factor. Clindamycin resistance was common, making empirical therapy likely to fail. Isolated E. coli species had a high proportion of MDR.

The bacteriology of diabetic foot ulcers and infections and incidence of Staphylococcus aureus Small Colony Variants

Introduction. Uninfected diabetes-related foot ulcer (DFU) progression to diabetes-related foot infection (DFI) is a prevalent complication for patients with diabetes. DFI often progresses to osteomyelitis (DFI-OM). Active (growing) Staphylococcus aureus is the most common pathogen in these infections. There is relapse in 40-60 % of cases even when the initial treatment at the DFI stage apparently clears infection.Hypothesis. S. aureus adopts the quasi-dormant Small Colony Variant (SCV) state during DFU and consequently infection, and when present in DFI cases also permits survival in non-diseased tissues as a reservoir to cause relapse.Aim. The aim of this study was to investigate the bacterial factors that facilitate persistent infections.Methodology. People with diabetes were recruited from two tertiary hospitals. Clinical and bacterial data was taken from 153 patients with diabetes (51 from a control group with no ulcer or infection) and samples taken from 102 patients with foot complications to identify bacterial species and their variant colony types, and then compare the bacterial composition in those with uninfected DFU, DFI and those with DFI-OM, of whom samples were taken both from wounds (DFI-OM/W) and bone (DFI-OM/B). Intracellular, extracellular and proximal 'healthy' bone were examined.Results. S. aureus was identified as the most prevalent pathogen in diabetes-related foot pathologies (25 % of all samples). For patients where disease progressed from DFU to DFI-OM, S. aureus was isolated as a diversity of colony types, with increasing numbers of SCVs present. Intracellular (bone) SCVs were found, and even within uninfected bone SCVs were present. Wounds of 24 % of patients with uninfected DFU contained active S. aureus. All patients with a DFI with a wound but not bone infection had previously had S. aureus isolated from an infection (including amputation), representing a relapse.Conclusion. The presence of S. aureus SCVs in recalcitrant pathologies highlights their importance in persistent infections through the colonization of reservoirs, such as bone. The survival of these cells in intracellular bone is an important clinical finding supporting in vitro data. Also, there seems to be a link between the genetics of S. aureus found in deeper infections compared to those only found in DFU.

Conservative Surgery for Diabetic Foot Osteomyelitis is not Associated With Longer Survival Time Without Recurrence of Foot Ulcer When Compared With Amputation

Conservative surgery of diabetic foot osteomyelitis (DFO) in which bone infection is removed without amputation could minimize the biomechanical changes associated with foot surgery. We hypothesize that patients who undergo conservative surgery will have a longer survival time without recurrence of foot ulcers and further amputations than those who undergo any type of amputation to treat DFO. We assessed a retrospective cohort of 108 patients who underwent surgery for DFO from January 2011 to December 2012. Patients were followed-up until May 2020. Reulceration and reamputation-free survival times were plotted using the Kaplan-Meier method and were calculated from the date of first surgery to recurrence, new amputation, or end of the study. A stratified log rank was used to study differences among groups. Cumulative survival without recurrences at 1, 5, and 8 years was 95%, 36%, and 29%, respectively, in patients who underwent conservative surgery and 95%, 43%, and 30%, respectively, in those undergoing amputation. Cumulative survival without a new amputation at 1, 5, and 8 years was 100%, 80%, and 80%, respectively, in patients who underwent conservative surgery and 98%, 82%, and 69%, respectively, in those undergoing amputation. No differences were found regarding either recurrence (log rank, P = .98) or new amputations (log rank, P = .64). In conclusion, conservative surgery is as safe as amputation to arrest bone infection in the feet of patients with diabetes. Conservative surgery was not associated with a lower rate of recurrence and new amputations than those patients who underwent amputations.

Prospective randomised placebo-controlled trial assessing the efficacy of silver dressings to enhance healing of acute diabetes-related foot ulcers

AIMS/HYPOTHESIS

Silver dressings are used for their antimicrobial properties but there is limited evidence of clinical benefit when managing diabetes-related foot ulcers (DFUs). We aimed to assess whether silver dressings in acute DFUs increased the proportion of ulcers healed compared with non-silver dressings.

METHODS

In this open-labelled, randomised controlled trial, consecutive individuals who presented to a tertiary multidisciplinary diabetic foot service with a DFU without osteomyelitis or tendon on view of <6 weeks' duration were randomised 1:1 via a computer-generated randomisation process to receive Acticoat (Smith & Nephew, England) dressing (silver group) or dressing without silver (control group) in addition to standard care. Stratified randomisation was performed to ensure that the presence of peripheral arterial disease and infection were equally managed within the two groups. The primary outcome was the proportion of ulcers healed at 12 weeks. Secondary outcomes included time to heal and to 50% ulcer reduction, rates of osteomyelitis and amputation, and need for and duration of antibiotics.

RESULTS

Seventy-six ulcers (55 participants) in the control group and 91 ulcers (63 participants) in the silver group were included. There was no difference in the proportion of ulcers healed by 12 weeks in the control vs silver group (75% vs 69%, p=0.49). After adjustment for presence of peripheral arterial disease, infection and initial ulcer size, silver dressing was not associated with odds of healing (OR 0.92; CI 0.26, 3.22; p=0.53). There was no difference in time to healing, progression to osteomyelitis, need for amputation, or duration of or need for antibiotic treatment.

CONCLUSIONS/INTERPRETATION

In individuals with acute DFUs without osteomyelitis or tendon on view, Acticoat silver dressings did not improve wound healing or reduce need for antibiotics compared with non-silver dressings.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12614001234606 FUNDING: Australian Diabetes Society-unrestricted research award.

Diabetic Foot Osteomyelitis: Is it all the Same?

Diabetic foot osteomyelitis (OM) requires a longer duration of therapy, a greater need for surgery and implies a higher rate of recidivism, a higher amputation risk, and lower treatment success. But do all bone infections behave the same way, require the same treatment, or imply the same prognosis? Actually, in clinical practice we can verify there are different clinical presentations of OM. The first one is that associated with the infected diabetic foot attack. It requires urgent surgery and debridement since "time is tissue." Clinical features and radiographs are enough for the diagnosis, and treatment should not be delayed. The second one is related to a sausage toe. It affects phalanges and it can be treated with a 6- or 8-week antibiotic course with a high rate of success. Clinical features and radiographs are sufficient for the diagnosis in this case. The third presentation is OM superimposed to Charcot's neuroarthropathy, which mainly comprises midfoot or hindfoot. It starts with a plantar ulcer in a foot that has developed a deformity. The treatment is based on an accurate diagnosis that often includes magnetic resonance, and requires a complex surgery to preserve the midfoot and to avoid recurrent ulcers or foot instability. The final presentation is that of an OM without large soft tissue compromise secondary to a chronic ulcer or a previous unsuccessful surgery secondary to minor amputation or debridement. There is often a small ulcer with a positive probe to bone test over a bony prominence. Diagnosis is made by clinical features, radiographs, and laboratory tests. Treatment includes antibiotic therapy guided by surgical or transcutaneous biopsy, but this presentation often requires surgery. Different presentations of OM mentioned above need to be recognized because the diagnosis, type of culture, antibiotic treatment, surgical treatment, and prognosis are different upon the presentation.

Surgical Diabetic Foot Infections: Is Osteomyelitis Associated With a Worse Prognosis?

It has been reported that patients with diabetes and foot ulcers complicated with osteomyelitis (OM) have a worse prognosis than those complicated with soft tissue infections (STI). Our study aimed to determine whether OM is associated with a worse prognosis in cases of moderate and severe diabetic foot infections requiring surgery. A retrospective series consisted of 150 patients who underwent surgery for diabetic foot infections. We studied the differences between OM versus STI. Furthermore, diabetic foot infections were reclassified into four groups: moderate STI (M-STI), moderate OM (M-OM), severe STI (S-STI), and severe OM (S-OM). The variables associated with prognosis were limb loss, length of hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing (both the initial ulcer and the postoperative wound). No differences in limb salvage, hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing were found when comparing OM with STI. Patients with M-O had a higher rate of recurrences after initial treatment and a longer time to healing when comparing with M-STI. We didn't find any differences between severe infections with or without OM. In conclusion, we have found in our surgical series of diabetic foot infections that OM is not associated with worse prognosis when comparing with STI regarding limb loss rate, length of hospital stays, duration of antibiotic treatment, recurrence of the infection, and time to healing. The results of the present series should further be confirmed by other authors.

Clinical Features, Inflammatory Markers, and Limb Salvage in Older Adults with Diabetes-Related Foot Infections

Little information exists about diabetic foot infections (DFIs) in older patients. We hypothesize that older patients with DFIs have different clinical features and worse outcomes than younger patients. We conducted a prospective observational study consisting of a cohort of patients with diabetes and moderate to severe DFIs. Patients included in the cohort were dichotomized into two groups using percentile 75 (P75) of age as the cut-off value. Patients aged > P75 presented with more comorbidities and foot-related complications, a higher rate of peripheral arterial disease (PAD), worse renal function (higher values of blood urea nitrogen and creatinine, and lower values of estimated glomerular filtration rate), and lower values of HbA1c compared with younger patients. Infection severity, microbiological features, and inflammatory markers were similar in both groups. In the multivariate analysis, minor amputations were associated with age > P75 (OR = 2.8, 95% CI 1.3-5.9, p <0.01), necrosis (OR = 4.2, 95% CI 1.8-10.1, p < 0.01), and CRP values (OR = 1.045, 95% CI 1.018-1.073, p < 0.01). Major amputations were associated with a history of amputation (OR = 4.7, 95% CI 1.3-16.7, p = 0.01), PAD (OR = 4.3, 95% CI 1.2-14.6, p = 0.01), and albumin values (OR = 0.344, 95% CI 0.130-0.913, p = 0.03). In conclusion, limb salvage can be achieved in older patients with diabetes-related foot infections at the same rate as in younger patients, despite the fact that they have more comorbidities and foot-related complications, a higher rate of PAD, and worse renal function.

Bacterial Diversity and Antibiotic Resistance in Patients with Diabetic Foot Osteomyelitis

This study analysed the bacterial diversity, antibiotic susceptibility, and resistance in patients with complications of diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between September 2019 and September 2022 and involved 215 outpatients with a diagnosis of DFO at a specialized diabetic foot unit. A total of 204 positive bone cultures were isolated, including 62.7% monomicrobial cultures, and 37.3% were formed with at least two microorganisms. We observed that Proteus spp., Coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Corynebacterium were the most frequently isolated microorganisms and accounted for more than 10% of the DFO cases. With stratification by Gram-positive (GP) and Gram-negative (GN) bacteria, we observed that 91.6% of cultures presented at least one GP bacteria species, and 50.4% presented at least one GN bacteria species. The most common GP species were CoNS (29%), S. aureus (25.8%), and Corynebacterium spp. (14%). The most frequent GN species consisted of Proteus spp. (32%), P. aeruginosa (23.3%), and E. coli (17.5%). The main antibiotics with resistance to GP-dominated infections were penicillins without β-lactamase inhibitor, and those in GN-dominated infections were sulfonamides and penicillins without β-lactamase. Significant differences were not observed in mean healing time in DFU with acute osteomyelitis (12.76 weeks (4.50;18)) compared to chronic osteomyelitis (15.31 weeks (7;18.25); p = 0.101) and when comparing cases with soft tissue infection (15.95 (6;20)) and those without such an infection (16.59 (7.25;19.75), p = 0.618). This study shows that when treatment of DFO is based on early surgical treatment, the type of DFO and the presence of soft infection are not associated with different or worse prognoses.

Herbal Products and Their Active Constituents for Diabetic Wound Healing-Preclinical and Clinical Studies: A Systematic Review

The purpose of this review is to provide verified data on the current knowledge acquired in preclinical and clinical studies regarding topically used herbal products and their active constituents (formulations and dressings) with diabetic wound healing activity. Moreover, herbal products and their active constituents used for diabetic wound infections, and various cellular and molecular mechanisms of their actions will also be described. The electronic databases were searched for articles published from 2012 to 2022. Publications with oral or systemic administration of herbal products in diabetic wound healing, published before 2012, available only as an abstract, or in languages other than English were excluded from the study. The 59 articles comparing topically used herbal products in diabetic wound healing treatment versus control treatments (placebo or active therapy) were selected. Herbal products through different mechanisms of action, including antimicrobial, anti-inflammatory, antioxidant activity, stimulation of angiogenesis, production of cytokines and growth factors, keratinocytes, and fibroblast migration and proliferation may be considered as an important support during conventional therapy or even as a substitute for synthetic drugs used for diabetic wound treatment.

The High Re-Ulceration Rate in Lower Extremity Amputation Intervention in Type 2 Diabetic Vietnamese Patients After 24-Month Follow-Up at Cho Ray Hospital, Vietnam

Diabetic foot ulcers (DFU) are a prevalent and severe disease with vascular and/or neurological complications, and if not diagnosed and treated promptly, it may rapidly deteriorate. Despite amputation or nonamputation treatment, there is still a high rate of re-ulceration. Previous studies have shown that the recurrence rate varies from 43% to 59% after 2 years. Currently, there is still a high rate of lower extremity amputation intervention, particularly above-the-ankle amputation, at Cho Ray Hospital in Vietnam, reaching 50%. The effectiveness of this intervention in the long term based on re-ulceration has not been evaluated in Vietnamese diabetic patients (DPs). This study aims to describe the long-term outcomes of amputation intervention in Type 2 DPs after 24 months and identify factors related to DFU recurrence in order to improve DFU management in low-middle-income countries like Vietnam. From January to June 2022, archived clinical and direct visit or phone follow-up data were collected and analyzed from diabetic foot ulcer patients with low extremity amputation who were treated at Cho Ray hospital from 2018 to 2020. The high re-ulceration rate in the 24th month was 29.8% (17/57), and the factor related to this outcome was "late diagnosis and care" (32.4 days vs 26.9 days with P = .03). Other potential factors (higher rates but no significant statistical difference with P > .05) included failure of HbA1c control greater than 9% (82.5% vs 67.5%), the severity of foot ulcers with TEXAS 3B (82% vs 60%), the number of years having diabetes (8.7 years vs 6.7 years), loss of monofilament sensation (82.5% vs 70.6%), and a history of diabetic foot ulcer (17.6% vs 10%). The re-ulceration after 24 months might depend on various clinical factors. Therefore, early diagnosis and care for diabetic foot ulcers could help reduce amputation rates and the risk of re-ulceration.

Biochemical predictors of diabetic foot osteomyelitis: A potential diagnostic role for parathormone

AIMS

The aims of this study were to evaluate parathormone (PTH) levels in people with diabetic foot ulcers (DFU) and investigate the relationship between PTH levels and osteomyelitis (OM) in this population.

MATERIALS AND METHODS

Eighty-eight patients were admitted for DFU in a tertiary-care centre from October 2021 to May 2022. OM was diagnosed by clinical, laboratory, and radiological evaluations. Laboratory measurements and clinical parameters were collected from medical records. Participants in the study were divided into two groups according to the diagnosis of OM (patients with OM, group 1 [n = 54] and patients without OM, group 2 [n = 34]).

RESULTS

Compared with group 2, patients in group 1 were younger and had a longer duration of diabetes. Erythrocyte sedimentation rate and fibrinogen were significantly higher in group 1 compared with group 2. PTH levels were significantly lower (group 1 vs. group 2, median [interquartile range] 16.2 (11.6, 31.0) vs. 23.7 (17.0, 38.1), p = 0.008) and alkaline phosphatase was significantly higher (97.0 (79.0, 112.0) vs. 88.0 (63.0, 107.0), p = 0.031) in group 1. In multiple linear regression analysis, the only independent predictors of PTH concentrations were alkaline phosphatase levels (β-coefficient 0.441, p < 0.001) and the presence of OM (β-coefficient -0.290, p = 0.038).

CONCLUSIONS

In a population of patients with diabetes and OM admitted to a tertiary university centre, PTH levels were lower as compared with diabetic individuals without OM. The OM and alkaline phosphatase levels were independent predictors of PTH levels in this selected population.

Vascular Endothelial Growth Factor Single Nucleotide Polymorphism +405 G/C (rs2010963) is associated with Levels, Infection Severity, and Amputation among South Indian Diabetic Foot Ulcer Patients

Background

The regulation of vascular endothelial growth factor (VEGF) by genetic factors in T2DM and DFU still requires thorough investigation. Hence, the present study aimed to investigate the association of VEGF +405 G/C in DFU subjects and correlate it with its circulatory levels, infection severity, and amputation rate.

Materials and Methods

This study registered a total of 754 participants of which group I: healthy controls (n = 297), group II: T2DM subjects (n = 242), and group III: DFU subjects (n = 215). Genotyping and levels of rs2010963 were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and ELISA, respectively.

Results

Results of the current study showed a clear decline in circulatory VEGF-A levels in DFU subjects. VEGF-A was decreased in DFU subjects with the mutant "CC" genotype. The mutant "CC" of VEGF +405G/C was also found to be more susceptible to ulcer grade (III and IV) and major amputations.

Conclusion

VEGF +405G/C SNP is associated with levels, infection severity, and amputation amongst South Indian DFU patients.

Cardiovascular/Stroke Risk Stratification in Diabetic Foot Infection Patients Using Deep Learning-Based Artificial Intelligence: An Investigative Study

A diabetic foot infection (DFI) is among the most serious, incurable, and costly to treat conditions. The presence of a DFI renders machine learning (ML) systems extremely nonlinear, posing difficulties in CVD/stroke risk stratification. In addition, there is a limited number of well-explained ML paradigms due to comorbidity, sample size limits, and weak scientific and clinical validation methodologies. Deep neural networks (DNN) are potent machines for learning that generalize nonlinear situations. The objective of this article is to propose a novel investigation of deep learning (DL) solutions for predicting CVD/stroke risk in DFI patients. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) search strategy was used for the selection of 207 studies. We hypothesize that a DFI is responsible for increased morbidity and mortality due to the worsening of atherosclerotic disease and affecting coronary artery disease (CAD). Since surrogate biomarkers for CAD, such as carotid artery disease, can be used for monitoring CVD, we can thus use a DL-based model, namely, Long Short-Term Memory (LSTM) and Recurrent Neural Networks (RNN) for CVD/stroke risk prediction in DFI patients, which combines covariates such as office and laboratory-based biomarkers, carotid ultrasound image phenotype (CUSIP) lesions, along with the DFI severity. We confirmed the viability of CVD/stroke risk stratification in the DFI patients. Strong designs were found in the research of the DL architectures for CVD/stroke risk stratification. Finally, we analyzed the AI bias and proposed strategies for the early diagnosis of CVD/stroke in DFI patients. Since DFI patients have an aggressive atherosclerotic disease, leading to prominent CVD/stroke risk, we, therefore, conclude that the DL paradigm is very effective for predicting the risk of CVD/stroke in DFI patients.

Effect of aqueous extract from root and leaf of Sphenocentrum jollyanum pierre on wounds of diabetic rats: Influence on wound tissue cytokines, vascular endothelial growth factor and microbes

ETHNOPHARMACOLOGICAL RELEVANCE

Sphenocentrum jollyanum is a flowering plant of the Menispermaceae family with bright yellow roots and wedged-shaped leaves. The plant is reputed to possess exceptional wound healing properties and used in folkloric medicine to dress chronic wounds.

AIM OF THE STUDY

Wound repair in a hyperglycemic state is known to be impaired and delayed making treatment a difficult challenge. This study sought how the aqueous extracts of root and leaf of Sphenocentrum jollyanum facilitated wound healing by modulating pro-inflammatory cytokines, vascular endothelial growth factor and microbial colonization on excision wound created in diabetic rats.

METHODS

Diabetes (blood glucose >250 mg/dl) was induced by feeding normal rats with high fat diet for 14 days after which intraperitoneal injection of low dose streptozotocin (35 mg/kg b.w.) was administered. Wounds were subsequently created and treatments administered afterwards for 14 days.

RESULTS

Administration of Sphenocentrum jollyanum root and leaf extracts both orally and topically (100 and 200 mg/kg b.w) significantly (p < 0.05) reduced secretion of pro-inflammatory cytokines (TNF-α, IL-6), number of microbial colonies (CFU/ml × 10²), activity of myeloperoxidase and significantly increased growth factor secretion on wounds of the diabetic rats. Histological evaluations of wound tissues of treated diabetic rats revealed matured tissue granulation, presence of new blood vessels, collagen and fibroblast with fewer inflammatory cells.

CONCLUSION

The use of Sphenocentrum jollyanum effectively enhanced wound healing which may be related to constituents identified by GC-MS analysis and can thus, be suggested as a therapeutic agent for diabetic wound management.

Exploring the Role of Staphylococcus aureus in Inflammatory Diseases

Staphylococcus aureus is a very common Gram-positive bacterium, and S. aureus infections play an extremely important role in a variety of diseases. This paper describes the types of virulence factors involved, the inflammatory cells activated, the process of host cell death, and the associated diseases caused by S. aureus. S. aureus can secrete a variety of enterotoxins and other toxins to trigger inflammatory responses and activate inflammatory cells, such as keratinocytes, helper T cells, innate lymphoid cells, macrophages, dendritic cells, mast cells, neutrophils, eosinophils, and basophils. Activated inflammatory cells can express various cytokines and induce an inflammatory response. S. aureus can also induce host cell death through pyroptosis, apoptosis, necroptosis, autophagy, etc. This article discusses S. aureus and MRSA (methicillin-resistant S. aureus) in atopic dermatitis, psoriasis, pulmonary cystic fibrosis, allergic asthma, food poisoning, sarcoidosis, multiple sclerosis, and osteomyelitis. Summarizing the pathogenic mechanism of Staphylococcus aureus provides a basis for the targeted treatment of Staphylococcus aureus infection.

Bacterial responsive hydrogels based on quaternized chitosan and GQDs-ε-PL for chemo-photothermal synergistic anti-infection in diabetic wounds

Clinically, systemic antibiotic therapy and traditional dressings care are not satisfactory in treating chronic diabetic ulcers (DU). Therefore, we presented sprayable antibacterial hydrogel for effective treatment of DU by using antibacterial macromolecules (quaternized chitosan, QCS, Mn ≈ 1.5 × 10⁵), photothermal antibacterial nanoparticles (ε-poly-l-lysine grafted graphene quantum dots, GQDs-ε-PL) and miocompatible macromolecules (benzaldehyde-terminated four-arm poly(ethylene glycol), 4 arm PEG-BA) as materials. The results revealed that the hydrogel could be in situ formed in 70-89 s through dynamic imine bonds crosslinking and exhibited a pH-dependent swelling ability and degradability. The hydrogel could respond to bacterial triggered acidic environment to play a synergistic effect of chemotherapy and xenon light irradiated PTT, leading to the rupture of the bacterial membrane and the inactivation of bacteria, promoting the migration and proliferation of fibroblast cell, enhancing the adhesion of platelet endothelial cell, and finally accelerating the healing of infected diabetic wound. Moreover, the hydrogel displayed self-healing, hemostatic, and biocompatible abilities, which could provide a better healing environment for wound and further promote wound healing. Hence, the multifunctional hydrogel is expected to be a potential dressing for the clinical treatment of DU.

How to build a limb salvage program

Patients with chronic limb-threatening ischemia (CLTI) are medically complex and continue to experience high rates of amputation, despite improved diagnosis and treatment. Limb salvage programs and multidisciplinary teams provide comprehensive patient care and have been associated with reduced amputation rates. Recent societal guidelines suggest the adoption of limb salvage programs to improve care of patients with CLTI. In this article, we describe the critical components of a limb salvage program and outline the following steps to aid in their construction: community and institution assessment, formation of a multidisciplinary team, provision of patient care, and monitoring outcomes and processes refinement.

Citric acid treatment of a diabetic leg ulcer infected with meticillin-resistant Staphylococcus aureus

Diabetic leg ulcers are difficult to manage. Infection by bacterial pathogens, such as meticillin-resistant Staphylococcus aureus (MRSA), is one of the most important reasons for non-healing of ulcers. If not treated in a timely manner, the ulceration may progress to septicaemia, amputation and even death. We report a successful treatment of a diabetic leg ulcer infected with MRSA, which was not responding to conventional antibiotic therapy and local wound care combined, with a local application of 3% citric acid ointment once daily for 30 days. The results indicated that its use may be a potential treatment in the management of hard-to-heal ulcers when all other options have been exhausted.

Antiseptic Agents for Chronic Wounds: A Systematic Review

In many parts of the world, antiseptic agents remain non-indicated in chronic wound care. In the current context of bacterial resistance to antibiotics and the development of new-generation antiseptic agents, wound antisepsis represents an asset for the prevention of wound infection. We aimed to evaluate four common antiseptic agents in chronic wound care complete healing. The review protocol was based on the Cochrane Handbook for Systematic Reviews of Intervention and devised in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement guidelines. Five databases and three clinical trials registries were searched from inception to 30 June 2021 without language restrictions. We included randomised trials evaluating the efficacy of antiseptic agents in chronic wound care in adults. Interventions considered were those using antiseptics for cleansing or within a dressing. Risk of bias was assessed using the bias excel tool provided by the Bristol Academy. Evidence quality was assessed using Grading of Recommendation Assessment, Development and Evaluation (GRADE) criteria. Of 838 studies, 6 were finally included, with a total of 725 patients. The included studies assessed iodine (cadexomer or povidone iodine) (n = 3), polyhexanide (n = 2), and octenidine (n = 1). Limited evidence suggested a better wound healing completion with iodine compared to saline (two randomised controlled trials (RCT), 195 patients, pooled RR 1.85 (95%CI (1.27 to 2.69)), moderate-quality evidence). There was not enough evidence to suggest a difference in wound healing using octenidine or polyhexamide. None of the antiseptic agents influenced adverse event occurrence compared to saline.

Role of miRNAs in diabetic neuropathy: mechanisms and possible interventions

Accelerating cases of diabetes worldwide have given rise to higher incidences of diabetic complications. MiRNAs, a much-explored class of non-coding RNAs, play a significant role in the pathogenesis of diabetes mellitus by affecting insulin release, β-cell proliferation, and dysfunction. Besides, disrupted miRNAs contribute to various complications, diabetic retinopathy, nephropathy, and neuropathy as well as severe conditions like diabetic foot. MiRNAs regulate various processes involved in diabetic complications like angiogenesis, vascularization, inflammations, and various signaling pathways like PI3K, MAPK, SMAD, and NF-KB signaling pathways. Diabetic neuropathy is the most common diabetic complication, characterized mainly by pain and numbness, especially in the legs and feet. MiRNAs implicated in diabetic neuropathy include mir-9, mir-106a, mir-146a, mir-182, miR-23a and b, miR-34a, and miR-503. The diabetic foot is the most common diabetic neuropathy, often leading to amputations. Mir-203, miR-23c, miR-145, miR-29b and c, miR-126, miR-23a and b, miR-503, and miR-34a are associated with diabetic foot. This review has been compiled to summarize miRNA involved in initiation, progression, and miRNAs affecting various signaling pathways involved in diabetic neuropathy including the diabetic foot. Besides, potential applications of miRNAs as biomarkers and therapeutic targets in this microvascular complication will also be discussed.

Phenotypic profile and antibiogram of biofilm-producing bacteria isolates from diabetic foot ulcers in Zaria, Nigeria

Background

Diabetic foot ulcers (DFUs) present with high morbidity and reduce patient's quality of life. There is a gross paucity of data on biofilm-producing bacteria in DFU Infection in North-Western Nigeria. The study sought to determine the biofilm-forming ability of bacteria isolates from DFUs and determine their antimicrobial susceptibility pattern in Zaria, North-Western Nigeria.

Materials and Methods

This hospital-based cross-sectional study of patients with DFUs was conducted from June 2018 to February 2020. Consecutive biopsies were aseptically collected. Bacteria were isolated and identified using a Microgen kit. Biofilm forming ability and antibiogram of isolates were determined using microtitre plate and disk diffusion methods, respectively.

Results

Of the 225 participants enrolled, males constituted the majority, 144 (64.0%) with 88 (36.0%) females, the median age of participants was 54 (48-60) years, and the age range was 36-77 years. A total of 172 bacteria were isolated, and 123 (71.5%) were biofilm producers. Staphylococcus aureus (26.7%) was the highest biofilm producer, while Citrobacter freundii and Stenotrophomonas maltophilia were the least biofilm producers, 1 (0.6%) each. A disproportionate resistance pattern was demonstrated among the biofilm and non-biofilm producers against the cephalosporins tested, ceftazidime (68% vs. 18%), ceftriaxone (50% vs. 8.0%) and cefotaxime (21% vs. 0.0%). About 46% and 68% of the biofilm producers were resistant to gentamycin and ciprofloxacin, respectively. While only 2% of the non-biofilm producers were resistant to imipenem, 11% of the biofilm producers were resistant to it.

Conclusion

These findings revealed a high proportion of biofilm-producing bacteria and were more resistant than non-biofilm producers.

Physicochemical and Biological Study of 99mTc and 68Ga Radiolabelled Ciprofloxacin and Evaluation of [99mTc]Tc-CIP as Potential Diagnostic Radiopharmaceutical for Diabetic Foot Syndrome Imaging

This paper presents the application of ciprofloxacin as a biologically active molecule (vector) for delivering diagnostic radiopharmaceuticals to the sites of bacterial infection. Ciprofloxacin-based radioconjugates containing technetium-99m or gallium-68 radionuclides were synthesised, and their physicochemical (stability, lipophilicity) and biological (binding study to Staphylococcus aureus and Pseudomonas aeruginosa) properties were investigated. Both the tested radiopreparations met the requirements for radiopharmaceuticals, and technetium-99m-labelled ciprofloxacin turned out to be a good radiotracer for the tomography of diabetic foot syndrome using SPECT.

The Profile of Microbiological Pathogens in Diabetic Foot Ulcers

Diabetic foot, a main complication of diabetes mellitus, renders the foot susceptible to infection, and may eventually lead to non-traumatic limb amputation due to the deterioration of diabetic foot ulcers (DFUs). Characterizing the pathogen spectrum and antibiotic susceptibility is critical for the effective treatment of DFUs. In the current study, the characteristics and antibiotic susceptibility of the pathogen spectrum were analyzed. Secretions from the DFUs of 102 patients were cultured, and dominant pathogens were identified by using test cards. Antibiotic susceptibility of dominant pathogens was assayed by the Kirby–Bauer assay. We found that the dominant pathogens varied with age, duration of diabetes, blood sugar control, and the initial cause of ulcers. Moreover, the dominant pathogens were susceptible to at least one antibiotic. However, the antibacterial efficacy of several commonly used antibiotics decreased from 2016 to 2019. Our study indicates that the identification of dominant pathogens and antibiotic susceptibility testing is essential for the treatment of DFUs with effective antibiotics, while the abuse of antibiotics should be strictly restrained to reduce the generation of antibiotic-resistant strains.

Role of an acidic environment in the treatment of diabetic foot infections: A review

Management of diabetic foot ulcers is the biggest challenge to the clinician, as conventional antibiotic therapies and local wound care have their own limitations. They are not effective for control of infections and promotion of healing because of cytotoxic effects. In view of cytotoxicity of routinely used topical antiseptic agents, this article focuses on the search of an ideal topical antiseptic agent that is safe and effective in controlling infectious agents and also in promoting the healing process. This review focuses on the use of various acids such as citric, acetic, hyaluronic, and hypochlorous acids as topical agents in diabetic foot infections. This article also focuses on the different roles of acids in the treatment of diabetic foot infections.