New insights in diabetic foot infection

Platelet-rich plasma as a potential antimicrobial agent against multidrug-resistant bacteria in diabetic foot infections

Diabetes mellitus is a global public health concern, with diabetic foot infections (DFIs) being common clinical complications among affected patients. Bacterial isolates resistant to commonly used antimicrobial drugs are becoming more prevalent in DFIs. Some research suggests that platelet-rich plasma (PRP) may inhibit bacterial growth, making it a promising biological therapy. Therefore, an in vitro experimental study was conducted on 53 multidrug-resistant (MDR) bacterial strains isolated from DFIs. The isolates were methicillin-resistant Staphylococcus aureus (MRSA), MDR Klebsiella pneumoniae, and MDR Pseudomonas aeruginosa. The antibacterial activity of PRP was assessed using Kirby-Bauer disk diffusion method, broth microdilution method, checkerboard synergy testing, and time-kill assay. The time-kill assay demonstrated that PRP's antibacterial efficacy peaked during the second hour of incubation for MRSA and Pseudomonas aeruginosa, but peaked at the first hour for Klebsiella pneumoniae. However, the PPR's efficiency against all isolates decreased after the peak point, with no antibacterial activity observed at the 24th h of incubation. Additionally, biofilm inhibition and eradication assays revealed that PRP has no effect on biofilm formation. As a result, PRP has the ability to inhibit bacterial growth, although this effect is transient and depends on the bacterial strain.

Efficient Photolysis of Multidrug-Resistant Polymicrobial Biofilms

Chronic wounds are prone to infections with multidrug-resistant bacteria, forming polymicrobial biofilms that limit treatment options and increase the risk of severe complications. Current cleansing options are insufficient to disrupt and remove tenacious biofilms; antibiotic treatments, on the other hand, often fall short against these biofilm-embedded bacteria. This study explores an non-antibiotic approach that extends beyond conventional porphyrin-based phototherapy by using blue light (BL) in conjunction with ferric ions (Fe(III)) to disrupt and eradicate biofilms. The dual not only degraded biofilm extracellular polymeric substances (EPS) in mono-species and polymicrobial biofilms by specifically targeting carboxyl-containing polysaccharides within the matrix but also exhibited broad-spectrum antimicrobial activity by affecting key components of the outer membrane and cell wall. Bacteria, such as K. pneumoniae, with compromised EPS after photolysis, demonstrated increased susceptibility to macrophage phagocytosis. Disruption of the polymicrobial biofilm structure also enhanced the bacterial susceptibility to bactericidal drugs. Treating wounds infected by mixed-species biofilm in diabetic mice demonstrated a substantial reduction in bacterial colonization and improved tissue repair. The BL-Fe(III) modality offers a safe, efficient alternative for managing chronic wound infections, making it ideal for repeated, non-invasive use at home, especially in resource-limited areas.

Prospective Observational Study of Microbiology of Infected Diabetic Foot Ulcers in a Tertiary-Care Hospital

INTRODUCTION

 Diabetic foot ulcers (DFUs) are a major cause of morbidity and mortality in people with diabetes mellitus. DFUs are the leading cause of hospitalisation for diabetic patients worldwide, especially in developing countries such as India. This study presents the microbiology profile of DFUs in a tertiary care hospital in the eastern part of India.

METHODOLOGY

 We conducted a prospective observational study for 150 DFU patients over a period of two years. We took samples from the DFUs of these patients, cultured them, and tested their antimicrobial susceptibility.

RESULTS

 Most diabetic foot infections (DFIs) in our study patients were caused by Gram-negative bacteria, mainly Escherchia coli (E. coli) (19.3%), Pseudomonas (14%), and Staphylococcus aureus (S. aureus) (12%). The majority of Gram-positive bacteria were susceptible to linezolid, followed by vancomycin and amoxycillin, while the majority of Gram-negative bacteria were susceptible to imipenem and meropenem, followed by ampicillin with sulbactam, amikacin, gentamicin, and ciprofloxacin. Our study revealed that 88.3% of the isolates were monomicrobial.

CONCLUSION

These findings demonstrated the importance of a local antibiogram, a microbiological exam, and antimicrobial susceptibility testing before starting antibiotic treatment for infections caused by DFUs. This protocol is different from the recommended guidelines for using empirical antibiotics.

Guided Conditional Diffusion Classifier (ConDiff) for Enhanced Prediction of Infection in Diabetic Foot Ulcers

Goal: To accurately detect infections in Diabetic Foot Ulcers (DFUs) using photographs taken at the Point of Care (POC). Achieving high performance is critical for preventing complications and amputations, as well as minimizing unnecessary emergency department visits and referrals. Methods: This paper proposes the Guided Conditional Diffusion Classifier (ConDiff). This novel deep-learning framework combines guided image synthesis with a denoising diffusion model and distance-based classification. The process involves (1) generating guided conditional synthetic images by injecting Gaussian noise to a guide (input) image, followed by denoising the noise-perturbed image through a reverse diffusion process, conditioned on infection status and (2) classifying infections based on the minimum Euclidean distance between synthesized images and the original guide image in embedding space. Results: ConDiff demonstrated superior performance with an average accuracy of 81% that outperformed state-of-the-art (SOTA) models by at least 3%. It also achieved the highest sensitivity of 85.4%, which is crucial in clinical domains while significantly improving specificity to 74.4%, surpassing the best SOTA model. Conclusions: ConDiff not only improves the diagnosis of DFU infections but also pioneers the use of generative discriminative models for detailed medical image analysis, offering a promising approach for improving patient outcomes.

Commonly associated aerobic microbial pathogens and their antibiotic susceptibility profile in diabetic foot ulcers in tertiary care centre in Western Maharashtra

PURPOSE

Diabetes mellitus (DM-II) is a metabolic disorder either due to reduced insulin production or reduced insulin sensitivity. Diabetic foot ulcer (DFU) is one of the most devastating complications of DM-II. This study was performed to assess commonly isolated micro-organisms and their anti-microbial sensitivity pattern in diabetic foot ulcers in a tertiary care centre in Western Maharashtra.

METHODS

Adult patients with a known case of DM-II with foot lesions, suspected to be a Diabetic Foot Infections (DFIs) at the tertiary care hospital from Aug 2022 to Sept 2022 were included in the study. After obtaining informed written consent, pus sample was collected with sterile swab from lesion's base and submitted to Microbiology Laboratory for aerobic culture and sensitivity.

RESULTS

Out of 56 enrolled patients, 47 (83.9%) patients tested positive for bacteriological growth and there was 'no growth' in 9 (16.07%) patients at the end of 48 h of aerobic incubation. There was male preponderance and patients were in age group of 35-85 years. The most commonly isolated micro-organisms were P. aeruginosa (17.8%), followed by S. aureus (14.2%), K. pneumonia and P. mirabilis (12.5% each). The resistance markers observed was ESBL producer, AmpC producer, MBL producer, Methicillin resistance and Inducible Clindamycin Resistance (ICR).

CONCLUSION

Due to the injudicious use of antibiotics, antibiotic resistance has been increased in all types of soft tissue infections. The empirical formula for the treatment of DFIs should be decided for given geographical reasons according to antimicrobial susceptibility profile from particular geographical area or health care institute.

Lytic activity of phages against bacterial pathogens infecting diabetic foot ulcers

Complications of diabetes, such as diabetic foot ulcers (DFUs), are common, multifactorial in origin, and costly to treat. DFUs are the cause of nearly 90% of limb amputations among persons with diabetes. In most chronic infections such as DFU, biofilms are involved. Bacteria in biofilms are 100-1000 times more resistant to antibiotics than their planktonic counterparts. Multidrug-resistant (MDR) Staphylococcus aureus and Pseudomonas aeruginosa infections in DFUs may require alternative therapeutic agents such as bacteriophages ("phages"). This study describes the lytic activity of phage cocktails AB-SA01 (3-phage cocktail) and AB-PA01 (4-phage cocktail), which target S. aureus and P. aeruginosa, respectively. The host range and lytic effect of AB-SA01 and AB-PA01 on a planktonic culture, single-species biofilm, and mixed-species biofilm were evaluated. In vitro testing showed that 88.7% of S. aureus and 92.7% of P. aeruginosa isolates were susceptible to AB-SA01 and AB-PA01, respectively, in the planktonic state. The component phages of AB-SA01 and AB-PA01 infected 66% to 94.3% of the bacterial isolates tested. Furthermore, AB-SA01 and AB-PA01 treatment significantly (p < 0.05) reduced the biofilm biomass of their hosts, regardless of the antibiotic-resistant characteristics of the isolates and the presence of a non-susceptible host. In conclusion, the strong lytic activity, broad host range, and significant biofilm biomass reduction of AB-SA01 and AB-PA01 suggest the considerable potential of phages in treating antibiotic-resistant S. aureus and P. aeruginosa infections alone or as coinfections in DFUs.

Effect of a multidisciplinary team approach on the management of diabetic foot ulcers on the Central Coast: A review of the Gosford Hospital High-Risk Foot Clinic

This retrospective cohort study aims to assess whether the implementation of a multidisciplinary approach in the Gosford Hospital High-Risk Foot Clinic improved outcomes of diabetic foot ulcers. Ulceration is a common foot complication of diabetes mellitus and greatly increases patient morbidity and mortality. Patients who attended at least one appointment at the Gosford Hospital High-Risk Foot Clinic in 2017 or 2019 were identified through the Gosford Hospital Podiatry department's records. The 2017 and 2019 cohorts were compared on measures of ulcer healing, incidence of amputation, incidence of vascular intervention and surgical debridement, percentage of patients admitted to hospital due to complications and use of systemic antibiotic therapy. Sixty-one patients in 2017 and 59 patients in 2019 met inclusion criteria, and from them, 207 ulcers were included. Between 2017 and 2019, there was a 6.2-week reduction in time to 100% ulcer healing in 2019 (p = 0.021), and 10.1% more ulcers healed within 52 weeks (p = 0.22, 95% confidence interval [CI] [-5.9%, 25.5%]). Whilst there was no significant difference in incidence of patients receiving amputation, there was an increased absolute number of amputations in 2019. Implementation of a multidisciplinary approach at the Gosford Hospital High-Risk Foot Clinic led to improvements in diabetic foot ulcer healing.

Independent association of history of diabetic foot with all-cause mortality in patients with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

BACKGROUND

Foot ulcers and/or infections are common long-term complications of diabetes and are associated with increased mortality, especially from cardiovascular disease, though only a few studies have investigated the independent contribution of these events to risk of death. This study aimed at assessing the association of history of diabetic foot with all-cause mortality in individuals with type 2 diabetes, independent of cardiovascular risk factors, other complications, and comorbidities.

METHODS

This prospective cohort study enrolled 15,773 Caucasian patients in 19 Italian centers in the years 2006-2008. Prior lower extremity, coronary, and cerebrovascular events and major comorbidities were ascertained by medical records, diabetic retinopathy by fundoscopy, diabetic kidney disease by albuminuria and estimated glomerular filtration rate, cardiovascular risk factors by standard methods. All-cause mortality was retrieved for 15,656 patients on 31 October 2015.

RESULTS

At baseline, 892 patients (5.7%) had a history of diabetic foot, including ulcer/gangrene and/or amputation (n = 565; 3.58%), with (n = 126; 0.80%) or without (n = 439; 2.78%) lower limb revascularization, and revascularization alone (n = 330; 2.09%). History of diabetic foot was associated with all-cause death over a 7.42-year follow-up (adjusted hazard ratio, 1.502 [95% confidence interval, 1.346-1.676], p < 0.0001), independent of confounders, among which age, male sex, smoking, hemoglobin A1c, current treatments, other complications, comorbidities and, inversely, physical activity level and total and HDL cholesterol were correlated independently with mortality. Both ulcer/gangrene and amputation alone were independently associated with death, with a higher strength of association for amputation than for ulcer/gangrene (1.874 [1.144-3.070], p = 0.013 vs. 1.567 [1.353-1.814], p < 0.0001). Both ulcer/gangrene/amputation and lower limb revascularization alone were independently associated with death; mortality risk was much higher for ulcer/gangrene/amputation than for revascularization (1.641 [1.420-1.895], p < 0.0001 vs. 1.229 [1.024-1.475], p = 0.018) and further increased only slightly for combined ulcer/gangrene/amputation and revascularization (1.733 [1.368-2.196], p < 0.0001).

CONCLUSIONS

In patients with type 2 diabetes, an history of diabetic foot event, including ulcer/gangrene, amputation, and lower limb revascularization, was associated with a ~ 50% increased risk of subsequent death, independent of cardiovascular risk factors, other complications and severe comorbidities, which were also significantly associated with mortality. The association with mortality was greatest for amputation, whereas that for revascularization alone was relatively modest.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.

Concomitants of Diabetic Foot Ulcer - A Review

BACKGROUND

Diabetes mellitus leading to foot ulcer is a serious complication, and it is considered a global epidemic. Neuropathyand high blood glucose levels are the primary causes of foot ulcers. Fifteen percent of people with diabetes develop foot ulcers, and these foot disorders are the main cause of lower extremity amputation among such patients.

INTRODUCTION

Complications of diabetic foot, affecting the lower extremities are common and quite complex and life-threatening. This review focuses on the life-threatening factors associated with diabetic foot ulcers and also the diagnosing and preventive measures. Neuropathy assessment and the range of foot ulcers were accurately examined.

CONCLUSION

Novel therapies focusing on the vascularity of the lower limbs, infection control, and ischemic control are being developed to mainly treat nonhealing ulcers.

Efficacy of the Novel Formulation of Topical Liothyronine and Liothyronine-insulin in Mild to Moderate Diabetic Foot Ulcer: A Randomized, Triple-blind Clinical Trial

BACKGROUND

Diabetic foot ulcer (DFU) is one of the challenging complications of chronic diabetes.

OBJECTIVE

The study aimed to investigate whether liothyronine (T3) and liothyronineinsulin (T3/Ins) topical preparations could significantly reduce the healing time of DFU.

METHODS

A prospective, randomized, placebo-controlled, patient-blinded clinical trial was conducted on patients with mild to moderate DFU, over a lesion area of no greater than 100 cm2. The patients were randomized to receive T3, T3/Ins, or honey cream 10% as the routine of care twice a day. Patients were examined for tissue healing weekly for 4 weeks, or until the total lesion clearance was observed, whichever was earlier.

RESULTS

Of 147 patients with DFUs, 78 patients (26 per group) completed the study and were included in the final evaluation. At the time of study termination, all participants in each of the T3 or T3/Ins groups were free of symptoms based on the REEDA score, while about 40% of participants in the control group were detected with each of grades 1, 2, or 3. A significant difference was observed on days 7, 14, and 21 of consumption of topical preparations (p-value < 0.001). The mean time to complete wound closure in the routine care group was about 60.6 days, while it was 15.9 and 16.4 days in T3 and T3/Ins groups, respectively. Within the T3 and T3/Ins groups, significant earlier wound closure was detected at day 28 (p-value < 0.001).

CONCLUSION

T3 or T3/Ins topical preparations are effective for wound healing and acceleration of wound closure in mild to moderate DFUs.

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.

Optimization of Host Cell-Compatible, Antimicrobial Peptides Effective against Biofilms and Clinical Isolates of Drug-Resistant Bacteria

Here, we describe the continued synthetic molecular evolution of a lineage of host-compatible antimicrobial peptides (AMP) intended for the treatment of wounds infected with drug-resistant, biofilm-forming bacteria. The peptides tested are variants of an evolved AMP called d-amino acid CONsensus with Glycine Absent (d-CONGA), which has excellent antimicrobial activities in vitro and in vivo. In this newest generation of rational d-CONGA variants, we tested multiple sequence-structure-function hypotheses that had not been tested in previous generations. Many of the peptide variants have lower antibacterial activity against Gram-positive or Gram-negative pathogens, especially variants that have altered hydrophobicity, secondary structure potential, or spatial distribution of charged and hydrophobic residues. Thus, d-CONGA is generally well tuned for antimicrobial activity. However, we identified a variant, d-CONGA-Q7, with a polar glutamine inserted into the middle of the sequence, that has higher activity against both planktonic and biofilm-forming bacteria as well as lower cytotoxicity against human fibroblasts. Against clinical isolates of Klebsiella pneumoniae, innate resistance to d-CONGA was surprisingly common despite a lack of inducible resistance in Pseudomonas aeruginosa reported previously. Yet, these same isolates were susceptible to d-CONGA-Q7. d-CONGA-Q7 is much less vulnerable to AMP resistance in Gram-negative bacteria than its predecessor. Consistent with the spirit of synthetic molecular evolution, d-CONGA-Q7 achieved a critical gain-of-function and has a significantly better activity profile.

Distribution of Causative Microorganisms in Diabetic Foot Infections: A Ten-Year Retrospective Study in a Tertiary Care Hospital in Central Malaysia

Diabetes mellitus is a global pandemic, especially in Southeast Asia. Diabetic foot infection (DFI) is a common complication of this condition and causes significant morbidity and mortality in those affected. There is a lack of locally published data on the types of microorganisms and empirical antibiotics being prescribed. This paper highlights the importance of local microorganism culture and antibiotic prescription trends among diabetic foot patients in a tertiary care hospital in central Malaysia. This is a retrospective, cross-sectional study of data taken from January 2010 to December 2019 among 434 patients admitted with diabetic foot infections (DFIs) using the Wagner classification. Patients between the ages of 58 and 68 years old had the highest rate of infection. Pseudomonas Aeruginosa, Proteus spp., and Proteus mirabilis appeared to be the most isolated Gram-negative microorganisms, and Staphylococcus aureus, Streptococcus agalactiae, and MRSA appeared to be the most common Gram-positive microorganisms. The most common empirical antibiotics prescribed were ampicillin/sulbactam, followed by ciprofloxacin and ceftazidime, and the most common therapeutic antibiotics prescribed were ampicillin/sulbactam, ciprofloxacin, and cefuroxime. This study could be immensely pertinent in facilitating future empirical therapy guidelines for treating diabetic foot infections.

Improving the Management and Treatment of Diabetic Foot Infection: Challenges and Research Opportunities

Diabetic foot infection (DFI) management requires complex multidisciplinary care pathways with off-loading, debridement and targeted antibiotic treatment central to positive clinical outcomes. Local administration of topical treatments and advanced wound dressings are often used for more superficial infections, and in combination with systemic antibiotics for more advanced infections. In practice, the choice of such topical approaches, whether alone or as adjuncts, is rarely evidence-based, and there does not appear to be a single market leader. There are several reasons for this, including a lack of clear evidence-based guidelines on their efficacy and a paucity of robust clinical trials. Nonetheless, with a growing number of people living with diabetes, preventing the progression of chronic foot infections to amputation is critical. Topical agents may increasingly play a role, especially as they have potential to limit the use of systemic antibiotics in an environment of increasing antibiotic resistance. While a number of advanced dressings are currently marketed for DFI, here we review the literature describing promising future-focused approaches for topical treatment of DFI that may overcome some of the current hurdles. Specifically, we focus on antibiotic-impregnated biomaterials, novel antimicrobial peptides and photodynamic therapy.

Emerging Antimicrobial and Immunomodulatory Fiber-Based Scaffolding Systems for Treating Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are one of the main complications of diabetes and are characterized by their complexity and severity, which are frequently aggravated by overexpressed inflammatory factors and polymicrobial infections. Most dressing systems offer a passive action in the treatment of DFUs, being frequently combined with antibiotic or immunomodulatory therapies. However, in many instances due to these combined therapies' inability to properly fight microbial presence, and provide a suitable, breathable and moist environment that is also capable of protecting the site from secondary microbial invasions or further harm, aggravation of the wound state is unavoidable and lower limb amputations are necessary. Considering these limitations and knowing of the urgent demand for new and more effective therapeutic systems for DFU care that will guarantee the quality of life for patients, research in this field has boomed in the last few years. In this review, the emerging innovations in DFU dressing systems via fiber-based scaffolds modified with bioactive compounds have been compiled; data focused on the innovations introduced in the last five years (2017-2022). A generalized overview of the classifications and constraints associated with DFUs healing and the bioactive agents, both antimicrobial and immunomodulatory, that can contribute actively to surpass such issues, has also been provided.

Inhibition of mecA and blaCTX-M from MRSA and ESBL strains of diabetic foot infection by screening antibiotics compound library: an in silico analysis

A computational approach was exploited towards new molecule designing to target the inhibition of resistant genes mecA and blaCTX-M in MRSA and ESBL strains cultured from diabetic foot infected patients. The bioinformatic analysis involves the prediction of protein structures for mecA and blaCTX-M employing the Prime module of Schrodinger. The interactions were examined with the control antibiotics using the modelled protein structures, which revealed that Cefixime and Amikacin showed the highest binding affinity with mecA and blaCTX-M, respectively. According to the predictions of pharmacophores, the ADHRN hypothesis for mecA protein and the ADHR hypothesis for blaCTX-M protein were obtained. Subsequently, the antibiotic compound library from Selleckchem was retrieved, and molecular interactions studies were carried out to explore the interaction profiling of mecA with Tobramycin and blaCTX-M with Acyclovir. Further, the stability of protein-ligand interactions was validated through molecular dynamics simulations. Overall, this study suggests that the predicted pharmacophore model provides in-depth knowledge for repurposing an antibiotic drug with effective inhibition to enhance its therapeutic activity in the currently used ones.Communicated by Ramaswamy H. Sarma.

Identification and antibiotic susceptibility of microorganisms isolated from diabetic foot ulcers: A pathological aspect

Diabetic foot ulcers infected with microorganisms increase the risk of amputation. The presence of drug-resistant bacteria in diabetic foot ulcers creates a big challenge during the treatment. The objective of the present study was to determine the bacterial prevalence and antibiotic resistance among bacteria isolated from Chinese patients with diabetic foot ulcers. The present study studied the microbial colonization of diabetic foot ulcers of patients from a single center in China. Wound swabs from 89 patients with diabetic foot ulcers were collected and the presence of microorganisms detected. The isolated microorganisms were subjected to antibiotic susceptibility testing by the disk diffusion method. Of 89 patients, 56 (62.9%) were male and 33 (37.1%) were female, the mean age of patients was 53.2±5.4 years, the mean duration of diabetes was 14.8±2.9 years, the mean random blood sugar was 301±87 mg/dl, mean HbA1c was 7.9±1.4%. Patients with Wanger ulcer grade III (36.0%; P=0.034) and patients within the weight range of 51-75 kg (59.6%; P=0.012) were significantly higher. The prevalence rate of diabetic foot ulcers was 11.3%. Among 153 microorganisms, gram-positive bacteria (52.3%) were more prevalent than gram-negative bacteria (44.4%). Most of the patients with polymicrobial infection were classified to have Wanger III ulcer grade diabetic foot ulcers. Staphylococcus aureus (38.2%) was the most predominant bacteria isolated followed by Staphylococcus epidermidis (29.2%) and Escherichia coli (28.1%). Most of the gram-positive and gram-negative bacteria were resistant to dicloxacillin (73.8%, P=0.021) and cefotaxime (50%), respectively and ~53.4% of the isolates were multi-drug resistance isolates, 61.8% of the Staphylococcus aureus were identified as methicillin-resistant Staphylococcus aureus and 61.8% of the gram-negative bacteria were extended-spectrum β-lactamase producers. Staphylococcus aureus and Escherichia coli were the predominant gram-positive and gram-negative bacteria isolated, respectively. Penicillin resistance was significantly higher among the gram-negative bacteria (P=0.019). Staphylococcus aureus and Escherichia coli were the predominant gram-positive and gram-negative bacteria isolated and levofloxacin and nitrofurantoin were the most effective antibiotics among the gram-positive and gram-negative bacterial isolates, respectively.

Diabetic Foot Ulcer Ischemia and Infection Classification Using EfficientNet Deep Learning Models

Motivation: Infection (bacteria in the wound) and ischemia (insufficient blood supply) in Diabetic Foot Ulcers (DFUs) increase the risk of limb amputation. Goal: To develop an image-based DFU infection and ischemia detection system that uses deep learning. Methods: The DFU dataset was augmented using geometric and color image operations, after which binary infection and ischemia classification was done using the EfficientNet deep learning model and a comprehensive set of baselines. Results: The EfficientNets model achieved 99% accuracy in ischemia classification and 98% in infection classification, outperforming ResNet and Inception (87% accuracy) and Ensemble CNN, the prior state of the art (Classification accuracy of 90% for ischemia 73% for infection). EfficientNets also classified test images in a fraction (10% to 50%) of the time taken by baseline models. Conclusions: This work demonstrates that EfficientNets is a viable deep learning model for infection and ischemia classification.

On diabetic foot ulcer knowledge gaps, innovation, evaluation, prediction markers, and clinical needs

Diabetic foot ulcers (DFUs) remain a very prevalent and challenging complication of diabetes worldwide due to high morbidity, high risks of lower extremity amputation and associated mortality. Despite major advances in diabetes treatment in general, there is a paucity of FDA approved technologies and therapies to promote successful healing. Furthermore, accurate biomarkers to identify patients at risk of non-healing and monitor response-to-therapy are significantly lacking. To date, research has been slowed by a lack of coordinated efforts among basic scientists and clinical researchers and confounded by non-standardized heterogenous collection of biospecimen and patient associated data. Novel technologies, especially those in the single and 'multiomics' arena, are being used to advance the study of diabetic foot ulcers but require pragmatic study design to ensure broad adoption following validation. These high throughput analyses offer promise to investigate potential biomarkers across wound trajectories and may support information on wound healing and pathophysiology not previously well understood. Additionally, these biomarkers may be used at the point-of-care. In combination with national scalable research efforts, which seek to address the limitations and better inform clinical practice, coordinated and integrative insights may lead to improved limb salvage rates.

Treatment of diabetic foot ulcers: review of the literature with regard to the TIME clinical decision support tool

OBJECTIVE

The aim of this clinically orientated paper is to offer an overview of diabetic foot ulcer (DFU) dressings generally, and more specifically, their use in the treatment of DFUs.

METHOD

The TIME clinical decision support tool (CDST) has been used as a clinical tool that can help clinicians bring together the different aspects of dressings for DFU treatment into a holistic approach to patient care.

RESULTS

DFUs are often difficult to heal, are painful and impact negatively on the individual's quality of life. Most DFU dressings are designed to support the healing of hard-to-heal wounds and represent one part of the management of DFUs. Apart from providing a moist environment, absorbing increased exudate, enhancing granulation and assisting in autolysis, the dressings need to be cost-effective. Wound dressing selection is based on clinical knowledge that ensures the dressing is most appropriate for the individual and the wound, taking into account the comorbidities that the individual may have.

CONCLUSION

This paper has highlighted how the use of the TIME CDST model can enhance clinical care and is a further tool clinicians should consider when developing and executing DFU treatment plans. Future research needs to focus on large multicentre studies using robust methodologies, given the current gaps in the evidence, to determine the effectiveness of dressing products for DFUs.

Microbiota of diabetic foot infections in a University Hospital in Bogotá, Colombia

The presence of infection in diabetic foot ulcers (DFU) is one of the main causes of lower limb amputation in the world. The presence of polymicrobial infections is usually the standard for isolation in such lesions, with Gram Positive (GP) germs being the main organisms involved, as is described in the global literature. However, some studies indicate a greater number of isolates with Gram Negative (GN) germs, reported mainly in the literature of Middle Eastern countries and in the tropics.

Antibacterial and Antifungal Efficacy of Medium and Low Weight Chitosan-Shelled Nanodroplets for the Treatment of Infected Chronic Wounds

Purpose

Medium versus low weight (MW vs LW) chitosan-shelled oxygen-loaded nanodroplets (cOLNDs) and oxygen-free nanodroplets (cOFNDs) were comparatively challenged for biocompatibility on human keratinocytes, for antimicrobial activity against four common infectious agents of chronic wounds (CWs) – methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Candida albicans and C. glabrata – and for their physical interaction with cell walls/membranes.

Methods

cNDs were characterized for morphology and physico-chemical properties by microscopy and dynamic light scattering. In vitro oxygen release from cOLNDs was measured through an oximeter. ND biocompatibility and ability to promote wound healing in human normoxic/hypoxic skin cells were challenged by LDH and MTT assays using keratinocytes. ND antimicrobial activity was investigated by monitoring upon incubation with/without MW or LW cOLNDs/cOFNDs either bacteria or yeast growth over time. The mechanical interaction between NDs and microorganisms was also assessed by confocal microscopy.

Results

LW cNDs appeared less toxic to keratinocytes than MW cNDs. Based on cell counts, either MW or LW cOLNDs and cOFNDs displayed long-term antimicrobial efficacy against S. pyogenes, C. albicans, and C. glabrata (up to 24 h), whereas a short-term cytostatic effects against MRSA (up to 6 h) was revealed. The internalization of all ND formulations by all four microorganisms, already after 3 h of incubation, was showed, with the only exception to MW cOLNDs/cOFNDs that adhered to MRSA walls without being internalized even after 24 h.

Conclusion

cNDs exerted bacteriostatic and fungistatic effects, due to the presence of chitosan in the outer shell and independently of oxygen addition in the inner core. The duration of such effects strictly depends on the characteristics of each microbial species, and not on the molecular weight of chitosan in ND shells. However, LW chitosan was better tolerated by human keratinocytes than MW. For these reasons, the use of LW NDs should be recommended in future research to assess cOLND efficacy for the treatment of infected CWs.

Optimization of photo-biomodulation therapy for wound healing of diabetic foot ulcers in vitro and in vivo

Unclear optical parameters make photo-biomodulation (PBM) difficult to implement in diabetic foot ulcer (DFU) clinically. Here, 12 wavelengths (400-900 nm) were used to conduct PBM to heal DFU wounds in vitro and in vivo. PBM at 10 mW/cm² and 0.5-4 J/cm² with all 12 wavelengths promoted proliferation of diabetic wound cells. In a mimic DFU (mDFU) rat model, PBM (425, 630, 730, and 850 nm, and a combination light strategy) promoted mDFU healing. The positive cell proliferation, re-epithelialization, angiogenesis, collagen synthesis, and inflammation were possible mechanisms. The combination strategy had the best effect, which can be applied clinically.

Do patients with diabetic foot ulcer need booster dose of tetanus vaccine?

Purpose

Diabetic foot ulcer is a public health concern around the world. These wounds are prone to a variety of infections including Clostridium Tetani that may lead to tetanus. The aim of this study was to evaluate the immunity status as a result of tetanus vaccination and other preventive measures in these patients.

Methods

We conducted a narrative review of previous studies which were related to the risk of tetanus infection in diabetic foot patients by searching electronic databases.

Results

It was found that usually tetanus antibody titers in diabetic patients are below the protective level and they are not appropriately vaccinated. Therefore, diabetes and lack of immunity, put diabetic foot ulcer patients more at risk of tetanus. But this problem is not given serious attention in diabetes care.

Conclusions

Thus, it is recommended to provide specific guidelines for tetanus vaccination and prophylaxis in diabetic patients. These recommendations can play a vital role in the prevention of diabetic foot ulcers complication.

Antimicrobial oxygen-loaded nanobubbles as promising tools to promote wound healing in hypoxic human keratinocytes

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Chitosan-shelled/perfluoropentane-filled OLNBs are innovative oxygen nanocarriers.

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OLNBs are biocompatible with human keratinocytes after cell internalization.

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OLNBs promote normoxia-like migration of hypoxic human keratinocytes.

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Chitosan-shelled OLNBs display antimicrobial activity against MRSA and C. albicans.

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Oxygen-loaded nanobubbles appear promising tools to treat infected chronic wounds.

Chronic wounds (CWs) are typically characterized by persistent hypoxia, exacerbated inflammation, and impaired skin tissue remodeling. Additionally, CWs are often worsened by microbial infections. Oxygen-loaded nanobubbles (OLNBs), displaying a peculiar structure based on oxygen-solving perfluorocarbons such as perfluoropentane in the inner core and polysaccharydes including chitosan in the outer shell, have proven effective in delivering oxygen to hypoxic tissues. Antimicrobial properties have been largely reported for chitosan. In the present work chitosan/perfluoropentane OLNBs were challenged for biocompatibility with human skin cells and ability to promote wound healing processes, as well as for their antimicrobial properties against methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans. After cellular internalization, OLNBs were not toxic to human keratinocytes (HaCaT), whereas oxygen-free NBs (OFNBs) slightly affected their viability. Hypoxia-dependent inhibition of keratinocyte migratory ability after scratch was fully reversed by OLNBs, but not OFNBs. Both OLNBs and OFNBs exerted chitosan-induced short-term bacteriostatic activity against MRSA (up to 6 h) and long-term fungistatic activity against C. albicans (up to 24 h). Short-term antibacterial activity associated with NB prolonged adhesion to MRSA cell wall (up to 24 h) while long-term antifungal activity followed NB early internalization by C. albicans (already after 3 h of incubation). Taken altogether, these data support chitosan-shelled and perfluoropentane-cored OLNB potential as innovative, promising, non-toxic, and cost-effective antimicrobial devices promoting repair processes to be used for treatment of MRSA- and C. albicans-infected CWs.

A, T. L, Lakshmanan A. Bacteriological Profile of Diabetic Foot Ulcers and Detection of Methicillin-Resistant Staphylococcus aureus and Extended-Spectrum β-Lactamase Producers in a Tertiary Care Hospital

Introduction

Diabetic foot infection is the most dreaded complication of diabetes mellitus and the commonest cause of hospitalization and limb amputation. Identification of the causative agent responsible for diabetic foot infection and the earliest initiation of appropriate antimicrobial therapy are vital for the control and prevention of the complication of diabetic foot ulcers. Therefore, we conducted this study to determine the bacteriological profile of diabetic foot ulcers and to detect methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL) producers in our institute.

Methodology

During the study period, samples were collected from the foot ulcers of 100 patients at the Diabetic Outpatient Department. The samples were processed according to the standard laboratory protocol, and bacterial isolates were identified. Antibiotic susceptibility testing was performed using the modified Kirby-Bauer disk diffusion technique, and results were interpreted according to the Clinical and Laboratory Standards Institute guidelines (CLSI 2016). A phenotypic test for MRSA detection was performed using cefoxitin (30 μg) disk. 

Results

The highest incidence of diabetic foot ulcers was observed in patients aged 41-50 years. There were 83 men and 17 women, with a male to female ratio of 4.882. Of the 100 collected samples, 73 were positive for microbial growth, and 27 samples showed no growth. Of the 73 positive cultures, monomicrobial infection was found in 48 patients, and polymicrobial infection was found in 25 patients. Gram-positive pathogens were isolated from 34 patients, and gram-negative microbes were isolated from 64 patients. Among all collected isolates (n=100), Staphylococcus aureus was the most predominant organism and Acinetobacter species was the least common (only two isolates). Among the gram-negative bacteria, Pseudomonas aeruginosa was predominant. All the isolated gram-positive bacteria were susceptible to vancomycin. Gram-negative bacteria were highly susceptible to colistin with the exception of Proteus species which is intrinsically resistant to colistin and it is not reported for Proteus species. ESBL producers were primarily found among Klebsiella species isolates (22.22%). Among 29 S. aureus isolates, 8 (27.5%) were found to be MRSA producers.

Conclusion

Based on the bacteriological profile of diabetic foot ulcers, S. aureus among the gram-positive isolates and P. aeruginosa among the gram-negative isolates were the predominant pathogens. Infections caused by multidrug-resistant bacteria such as MRSA and ESBL producers have been reported with increasing frequency. According to the antibiotic susceptibility pattern, treatment can be initiated, continued, or altered, thereby reducing morbidity in patients with diabetic foot ulcers.

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.

Point-of-care testing for bacterial infection in diabetic foot ulcers: a prospective cohort study

OBJECTIVE

To appraise the performance of a new point-of-care wound infection detection kit in diabetic foot ulcers (DFUs), using clinician opinion as the primary comparator. The proprietary swab-based chromatic Glycologic (Glycologic Ltd., UK) detection kit used in this study is designed to detect host response to pathogenic levels of bacteria in wounds.

METHOD

In high-risk podiatry clinics, patients with DFUs were recruited and infection detection kit test results compared with initial clinician opinion. Chi-squared tests, principal component analysis (PCA) and multiple regression analysis were performed to determine which variables were possibly associated with infection. The variables considered were patients' wound parameters, wider vascular comorbidity and demographics.

RESULTS

A total of 136 patients, providing 383 wound swabs, were included in the study. Total agreement in terms of DFU wound assessment for infection-between podiatrists' clinical opinion and Glycologic kit test result-was observed in 79% of cases (301/383). For 56 of the 349 negative infection detection kit test results (16%), podiatrists identified a 'possible' or 'definite' infection. Conversely, in 14 of the 307 cases (4.6%) where podiatrists deemed the wound 'not infected', the infection detection kit test showed a colour change. Regression analysis and PCA showed that clinical signs of wound infection, namely erythema, purulence and odour, were all significantly associated with both a positive clinical opinion and infection detection kit test result. However, in the case of the infection detection kit, a patient's number of lesions and vascular comorbidities were also significantly correlated with a positive test result.

CONCLUSION

A host response to critical pathological levels of bioburden in a wound-as detected with the infection detection kit-may partly be determined by an individual patient's (vascular) health and therefore be person-specific. Further research is indicated to determine the relationship between an infection detection kit test result and the microbiological status of the wound.

Molecular characterization of methicillin-resistant Staphylococcus aureus among insulin-dependent diabetic individuals in Brazil

BACKGROUND

People with diabetes mellitus, especially insulin-dependent diabetic patients, are a risk group for staphylococcal infections. Asymptomatic infection with Staphylococcus aureus is common and favors dissemination of the microorganism, rendering these individuals a source of infection. This study aimed to characterize the resistance profile, clonal profile and sequence type, as well as to analyze the prevalence and risk factors for nasal and oropharyngeal carriage of methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) isolated from insulin-dependent diabetic individuals in the city of Botucatu, SP, Brazil.

METHODS

Staphylococcus aureus was collected from the nasopharynx and oropharynx of 312 community-dwelling insulin-dependent diabetic individuals over a period of 3 years (October 2015 to December 2018). The isolates were characterized by susceptibility profiling, detection of the mecA gene, SCCmec typing, and molecular typing by PFGE and MLST. The risk factors associated with S. aureus and MRSA carriage were determined by logistic regression analysis.

RESULTS

The overall prevalence of colonization with S. aureus and MRSA was 30.4% and 4.8%, respectively. Fifteen of the 112 S. aureus isolates carried the mecA gene; SCCmec type IV was identified in 10 isolates, SCCmec type I in three, and SCCmec type II in two. Among the 15 resistant isolates (MRSA), four were susceptible to oxacillin/cefoxitin by the disc diffusion method and one MSSA isolate was resistant to sulfamethoxazole/trimethoprim. The analysis of risk factors revealed a protective effect of age and lung disease, while lower-extremity ulcers were a risk factor for S. aureus. For MRSA, only male gender was significantly associated as a risk factor in multivariate analysis. Clonal profile analysis demonstrated the formation of clusters among MRSA isolates from different patients, with the identification of ST5-IV, ST5-I, and ST8-IV. Isolates carrying ST398 were identified among MSSA and MRSA (ST398-IV).

CONCLUSION

Our findings reinforce the importance of epidemiological studies of S. aureus carriage, especially in populations at high risk of infections such as diabetics. The data suggest widespread dissemination of MRSA in the population of insulin-dependent diabetic patients studied, as well as the emergence of important lineages among these individuals.

Predictive ability of LRINEC score in the prediction of limb loss and mortality in diabetic foot infection

It was aimed to analyze the effectiveness of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score in predicting amputation and mortality in diabetic foot infection (DFI). Data of 416 patients who were hospitalized for DFI were recorded retrospectively. LRINEC scores were calculated for each patient from laboratory data. The diagnostic performance of LRINEC score was investigated in amputated/nonamputated and survived/deceased patient groups. Median LRINEC score of patients who underwent amputation was higher than those without amputation (P < 0.001). The area under the curve (AUC) value for LRINEC score was 0.638 with the cut-off point of ≥5 in predicting amputation. Median LRINEC score of deceased patients was higher than those who survived (P= 0.022). AUC value for LRINEC score was 0.663 with the cut-off point of ≥7 in predicting mortality. LRINEC score may be a promising scoring system in predicting both amputation and mortality in DFI.

Spectral and Antibiotic Susceptibility of Pathogens Isolated from Saudi Patients with Diabetic Foot Infections

Diabetic foot infections (DFIs) are a significant health issue and a common complication among patients with diabetes. To develop antibiotic therapy for these high-risk patients, the current study evaluates the scope of DFIs and identifies the causing microbes. It also measures spectrum and antibiotic susceptibility of the pathogens isolated from adults with DFIs in Saudi Arabia. To achieve the study objectives, a cross-sectional study was implemented and the baseline characteristics for 44 patients with DFIs were defined. Optimal aerobic and anaerobic microbiological techniques were utilized to culture specimens isolated from infected foot ulcers. The standard microbiological methods were employed to identify the bacterial isolates and antibiotic susceptibility testing was conducted following the procedures of the Clinical and Laboratory Standards Institute (CLSI). Results showed that 12 microorganisms were isolated from the participants’ diabetic foot ulcers. Staphylococcus Aureus was ranked first because it appeared in 29 (65.9%) cases. Streptococcus Agalactiae was ranked second and multi-microbial infections were also found. Most of the organisms were susceptible to Vancomycin, Ciprofloxacin, and Cefalexin, but they were resistant to Methicillin, Gentamicin, and Ampicillin antibiotics. Staphylococcus Aureus was most sensitive to Ciprofloxacin, while it was resistant to Methicillin. About 10% of the isolates were multidrug-resistant. The study concludes that while Vancomycin should be used empirically for Gram-positive isolates, Ciprofloxacin can be taken into consideration for most of the Gram-negatives aerobes. Based on including various microorganisms and the advent of multidrug-resistant strains, proper culture and sensitivity testing are necessary prior to the empirical therapy.

Diabetic foot infection and osteomyelitis. Are deep-tissue cultures necessary?

Introduction

Diabetic foot infections (DFIs) are common and difficult to treat. The objective of this study was to compare swab and tissue cultures as indicators of appropriate treatment of DFIs.

Methods

This is a prospective study conducted during a 4-year period. All patients with DFIs and/or diabetic foot osteomyelitis (DFO) admitted to the University Hospital of Heraklion, Greece, were included. Clinical data were collected, while cultures taken with swabs and/or tissue biopsies were used as indicators of the microbiological cause and the appropriate treatment.

Results

In total, 83 individuals (62.7% males) with mean age of 72 years, were enrolled. Coexisting osteomyelitis was present in 18.1%. From tissue and pus cultures, 131 and 176 pathogens, respectively, were isolated. Gram-positive aerobes were the most common microorganisms, followed by Gram-negatives. Infection was polymicrobial in 40 (70.2%) out of 57 patients with tissue culture and in 54 (75.0%) out of 72 with pus culture. Microbiological results from tissue cultures were compatible with those from pus at a rate of 80%, while in cases of osteomyelitis concordance reached 100%. Multidrug-resistant organisms (MDROs) were isolated from 32 (24.4%) tissue and 44 (25%) pus cultures (p=0.910). Initial empirical antimicrobial treatment was considered inappropriate in 44.6% of cases.

Conclusions

A high concordance between easily taken swab cultures and those taken by biopsy was noted, especially in DFO. This was helpful for early change to appropriate treatment in cases where MDROs were isolated and empirical treatment was inappropriate. Further research is needed to confirm this observation in clinical practice.

Virulence factors and clonal diversity of Staphylococcus aureus in colonization and wound infection with emphasis on diabetic foot infection

Foot ulcer is a common complication in diabetic subjects and infection of these wounds contributes to increased rates of morbidity and mortality. Diabetic foot infections are caused by a multitude of microbes and Staphylococcus aureus, a major nosocomial and community-associated pathogen, significantly contributes to wound infections as well. Staphylococcus aureus is also the primary pathogen commonly associated with diabetic foot osteomyelitis and can cause chronic and recurrent bone infections. The virulence capability of the pathogen and host immune factors can determine the occurrence and progression of S. aureus infection. Pathogen-related factors include complexity of bacterial structure and functional characteristics that provide metabolic and adhesive properties to overcome host immune response. Even though, virulence markers and toxins of S. aureus are broadly similar in different wound models, certain distinguishing features can be observed in diabetic foot infection. Specific clonal lineages and virulence factors such as TSST-1, leukocidins, enterotoxins, and exfoliatins play a significant role in determining wound outcomes. In this review, we describe the role of specific virulence determinants and clonal lineages of S. aureus that influence wound colonization and infection with special reference to diabetic foot infections.

Efficacy of phage cocktail AB-SA01 therapy in diabetic mouse wound infections caused by multidrug-resistant Staphylococcus aureus

BACKGROUND

Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (phages) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I clinical trials, in treatment of multidrug-resistant (MDR) S. aureus infections.

RESULTS

Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. At the end of the treatment period, there was a significant decrease (p < 0.001) in bacterial load and wound size in infected phage- and vancomycin-treated groups compared with infected saline-treated mice. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No mortality was recorded associated with infections, and post-mortem examinations did not show any evident pathological lesions other than the skin wounds. No adverse effects related to the application of phages were observed.

CONCLUSION

Topical application of phage cocktail AB-SA01 is effective, as shown by bacterial load reduction and wound closure, in the treatment of diabetic wound infections caused by MDR S. aureus. Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.

Microbial spectrum, antibiotic susceptibility profile, and biofilm formation of diabetic foot infections (2014-18): a retrospective multicenter analysis

This study identifies the risk factors, microbiological properties, antimicrobial susceptibility patterns, mortality, and clinical complications associated with organisms causing diabetic foot infections (DFIs) with or without antibiotic treatment using data from a retrospective multicenter surveillance. Specimens collected from different hospitals were cultured and the extended-spectrum β-lactamase (ESBL) excretion was estimated. The antibacterial susceptibility pattern and biofilm formation were completed along with the recommended standard methods. Overall, 792 diabetic foot patients (DFPs) were enrolled and a total of 1803 causative organisms were isolated. Polymicrobial infection was identified in 48.5% of the patients. The isolated Gram-positive pathogens (46.7%) were higher than Gram-negative (38.6%) or anaerobes (7.9%). The predominant pathogens were S. aureus (22.2%), methicillin-resistant S. aureus (7.7%), Enterococcus spp. (12.8%), Pseudomonas aeruginosa (9.4%), E. coli (7.9%), Klebsiella spp. (7.5%), Proteus mirabilis (8.9%), coagulase negative staphylococci (CoNS) (6.6%), anaerobic organisms (5.9%), and fungi (2.3%). Vancomycin and clindamycin exhibited no activity against Gram-positive bacteria. However, meropenem and imipenem displayed high activity against the Gram-negative isolates. Out of the 765 tested strains, 251 showed moderate (15.8%) to high (34%) level biofilm-producing phenotype. DFIs were widespread among the diabetic patients with different microbial etiology and the major organisms were aerobic organisms. Our findings may provide an insight into the development of appropriate therapeutic strategies for the management of DFIs.

In Vitro and In Vivo Antibiotic Capacity of Two Host Defense Peptides

Two nonamidated host defense peptides named Pin2[G] and FA1 were evaluated against three types of pathogenic bacteria: two (Staphylococcus aureus UPD13 and Pseudomonas aeruginosa UPD3) isolated from diabetic foot ulcer patients, and another (Salmonella enterica serovar Typhimurium [ATCC 14028]) from a commercial collection. In vitro experiments showed that the antimicrobial performance of the synthetic peptides Pin2[G] and FA1 was modest, although FA1 was more effective than Pin2[G]. In contrast, Pin2[G] had superior in vivo anti-infective activity to FA1 in rabbit wound infections by the diabetic foot ulcer pathogens S. aureus UPD13 and P. aeruginosa UPD3. Indeed, Pin2[G] reduced bacterial colony counts of both S. aureus UPD13 and P. aeruginosa UPD3 by >100,000-fold after 48 to 72 h on skin wounds of infected rabbits, while in similar infected wounds, FA1 had no major effects at 72 to 96 h of treatment. Ceftriaxone was equally effective versus Pseudomonas but less effective versus S. aureus infections. Additionally, the two peptides were evaluated in mice against intragastrically inoculated S. enterica serovar Typhimurium (ATCC 14028). Only Pin2[G] at 0.56 mg/kg was effective in reducing systemic (liver) infection by >67-fold, equivalent to the effect of treatment with levofloxacin. Pin2[G] showed superior immunomodulatory activity in increasing chemokine production by a human bronchial cell line and suppressing polyinosinic-polycytidylic acid (poly[I:C])-induced proinflammatory IL-6 production. These data showed that the in vitro antimicrobial activity of these peptides was not correlated with their in vivo anti-infective activity and suggest that other factors such as immunomodulatory activity were more important.

Exosome laden oxygen releasing antioxidant and antibacterial cryogel wound dressing OxOBand alleviate diabetic and infectious wound healing

Lack of oxygen, reduced vascularization, elevated oxidative stress, and infection are critical clinical hallmarks of non-healing chronic diabetic wounds. Therefore, delivering oxygen, inducing angiogenesis, and management of oxidative stress and infection may provide newer and improved therapeutic avenues for better clinical outcomes in diabetic wound healing. Here, we report the development and evaluation of an exosome laden oxygen releasing antioxidant wound dressing OxOBand to promote wound closure and skin regeneration in diabetic wounds. OxOBand is composed of antioxidant polyurethane (PUAO), as highly porous cryogels with sustained oxygen releasing properties and supplemented with adipose-derived stem cells (ADSCs) exosomes. Exosomes engulfed by the cells enhanced the migration of human keratinocytes and fibroblasts and increased the survival of human neuroblastoma cells under hyperglycemic conditions. OxOBand facilitated faster wound closure, enhanced collagen deposition, faster re-epithelialization, increased neo-vascularization, and decreased oxidative stress within two weeks as compared to untreated diabetic control wounds. The dressing promoted the development of mature epithelial structures with hair follicles and epidermal morphology similar to that of healthy skin. In clinically challenging infected diabetic wounds, these dressings prevented infection and ulceration, improved wound healing with increased collagen deposition, and re-epithelialization. Altogether, OxOBand is a remarkably newer treatment strategy for enhanced diabetic wound healing and may lead to novel therapeutic interventions for the treatment of diabetic ulcers.

Prediction of stump healing in lower limb amputation: a narrative review

Both types of diabetes, as well as different forms of acquired diabetes, are associated with diabetic peripheral neuropathy. Diabetic foot ulcers (DFU) is the condition most commonly related to somatic peripheral neuropathy, often leading to gangrene and limb amputation. Independent from large-vessel disease, sensory loss may result in DFU development and even amputation. The crucial part of any lower limb amputation is the stump healing process, which represents the central goal of postoperative management. Despite the importance attributed to this process, a standard set of guidelines regarding efficient healing methods is yet to be formulated. Health professionals are faced with the challenge of assessing the different risk factors and deciding which has a greater influence on the stump healing rate. There is currently an insufficient number of studies regarding factors effecting lower limb amputation. The main purpose of this review is to discuss the markers that can be helpful in the prediction of stump healing in patients who have undergone lower limb amputation.

Molecular Interactions between Pathogens and the Circadian Clock

The daily periodicity of the Earth's rotation around the Sun, referred to as circadian (Latin "circa" = about, and "diem" = day), is also mirrored in the behavior and metabolism of living beings. The discovery that dedicated cellular genes control various aspects of this periodicity has led to studies of the molecular mechanism of the circadian response at the cellular level. It is now established that the circadian genes impact on a large network of hormonal, metabolic, and immunological pathways, affecting multiple aspects of biology. Recent studies have extended the role of the circadian system to the regulation of infection, host-pathogen interaction, and the resultant disease outcome. This critical review summarizes our current knowledge of circadian-pathogen interaction at both systemic and cellular levels, but with emphasis on the molecular aspects of the regulation. Wherever applicable, the potential of a direct interaction between circadian factors and pathogenic macromolecules is also explored. Finally, this review offers new directions and guidelines for future research in this area, which should facilitate progress.

The role of soluble urokinase plasminogen activator receptor (suPAR) in the diagnostics of diabetic foot infection

Background: To investigate the role of soluble urokinase plasminogen activator receptor (suPAR) in the diagnosis of diabetic foot infection and to determine whether it is superior to other infection markers like leukocyte, neutrophil, erythrocyte sedimentation rate, c-reactive protein and procalcitonin.Methods: The present prospective study consisted of four groups: Group 1, healthy volunteers (n = 38); Group 2, patients without diabetic foot ulcers (n = 40); Group 3, diabetic patients with uninfected foot ulcers (n = 33); and Group 4, patients who had diabetic foot infection (n = 48). In each group, the leukocyte, neutrophil, erythrocyte sedimentation rate, c-reactive protein and procalcitonin and suPAR levels were examined. The results were then statistically compared. In addition, the patients in Group 4 were further divided according to the presence of mild, moderate, and severe infection. Also osteomyelitis were evaluated in Group 4 and statistically compared.Results: All infection markers were significantly higher in group 4 patients than those in the other three groups (p < .05). Similarly, all infection markers in the severe diabetic foot infection group were statistically higher than mild diabetic foot infection group (p < .05); however, only suPAR and erythrocyte sedimentation rate were significantly high in cases with osteomyelitis (p < .05). In the receiver operating characteristic analysis, the optimal cut-off value for suPAR was determined to be 2.8 ng/ml, and the sensitivity and specificity above this value were 95.8% and 82.8%, respectively.Conclusions: The current study demonstrated that suPAR might be used as a supportive diagnostic method for the diagnosis of diabetic foot infections.

Impact of Photobiomodulation and Condition Medium on Mast Cell Counts, Degranulation, and Wound Strength in Infected Skin Wound Healing of Diabetic Rats

Background: Numerous people suffer from diabetes mellitus (DM) and resultant diabetic foot ulcers (DFU), which lack effective treatment. Photobiomodulation (PBM) has accelerated wound healing in diabetic animals and patients in some studies. However, there is scant information on the number and activation state of skin mast cells (MCs) in PBM-treated diabetic wounds. Objective: We intend to assess the influence of the number of MCs and degranulation in the remodeling step of an infected wound model on wound strength and its microbial flora in a type 1 DM (T1DM) rat model by administration of PBM, condition medium (CM) derived from human bone marrow mesenchymal stem cells (hBMMSCs), and the combination of PBM+CM. Methods: We prepared CM by culturing hBMMSCs. T1DM was induced in 72 rats and, after 1 month, we created one excisional wound in each rat. All wounds were infected with methicillin-resistant Staphylococcus aureus (MRSA). We divided the rats into four groups: (n = 18): (i) control; (ii) PBM; (iii) CM, and (iv) PBM+CM. On days 4, 7, and 15, we conducted microbiological, tensiometrical, and stereological analyses. The type of MCs (T1MCs, T2MCs, or T3MCs) and total number of MCs (TOMCs) were counted by light microscopy. Results: On day 15, the PBM+CM, PBM, and CM groups had significantly increased wound strength compared with the control group. There was a significant decrease in colony-forming units (CFU) at all time points in the PBM+CM and PBM groups. The PBM+CM and PBM groups had more stable MCs (T1MCs), less significant degranulated MCs (T2MCs), less significant disintegrated MCs (T3MCs), and less significant TOMCs compared with the control group at all time points. Conclusions: PBM+CM and PBM treatments significantly increased the healing process in an ischemic and MRSA-infected wound model of T1DM rats. PBM+CM and PBM significantly decreased both TOMCs and their degranulation, and significantly decreased CFU.

Bacterial-binding dressings in the management of wound healing and infection prevention: a narrative review

The aim of this review was to present the clinical data on the use of the family of bacterial-binding dressings (Sorbact; dialkylcarbamoyl chloride-coated) in the treatment of a variety of acute and chronic wounds. The findings are discussed in terms of the effectiveness of the bacterial-binding dressings on bacterial bioburden reduction, infection prevention, initiation/progression of wound healing and cost-effectiveness. The evidence in support of the bacterial-binding dressings is strongest in the area of infection prevention in surgical wounds, with several controlled trials showing the prophylactic benefit of the dressing in these wounds. Wound bioburden management in chronic wounds is supported by a number of clinical studies. In total, 29 published clinical studies (with a total of 4044 patients) were included in this review.

A study to identify bacteriological profile and other risk factors among diabetic and non-diabetic foot ulcer patients in a Guyanese hospital setting

Diabetic foot infection is a global epidemic and a major public health concern. Development of microbial resistance to many antimicrobial agents in foot ulcer leads to serious complications. Therefore, the study aims to identify the microbiological profile and the potential risk factors among diabetic and non-diabetic foot ulcer patients. A prospective cross sectional study was carried out among 183 ulcer patients from diabetic foot clinic and wound dressing clinic at the public health hospital, Guyana. A total of 254 bacteria were isolated from the study with an average of 1.4 organism per lesion. Gram negative bacteria (63.0%) were prevalent than gram positive bacteria (37.0%) in this study. Among DF patients, Pseudomonas aeruginosa (18.8%) was the most common isolate followed by Escherichia coli (13.9%) among gram negative group. Were as MRSA (12.1%) followed by MSSA (7.9%) dominated among gram positive group in diabetic foot patients. Almost 42.1% (95% CI 34.8-49.6) of the infections were caused by poly-microbial. Interestingly, a stepwise logistic regression model determined increasing age and lack of health education as independent risk factor identified for acquiring an MDR wound infection (OR = 1.1; p ≥ 0.05; 95% CI 1.0-1.1). Mild, moderate and severe infection among MDR and NMDR patients were recorded as 45.3% (95% CI 32.8-58.3), 26.5% (95% CI 16.3-39.1), 28.1% (95% CI 17.6-40.8) and 51.3% (95% CI 41.9-60.5), 32.8% (95% CI 24.4-42.0), 16.0% (95% CI 9.9-23.8). Therefore, it is concluded that there's an urgent need for surveillance of resistant bacteria in diabetic foot infections to reduce the risk of major complications.

Antimicrobial susceptibility pattern of aerobes in diabetic foot ulcers in a South-Indian tertiary care hospital

PURPOSE

Diabetic foot infections (DFIs) are major public health concerns. In the view of the ever increasing burden of multidrug-resistant (MDR) organisms, improving the use of antimicrobial agents (AMAs) is a national priority. Objective of the study was to determine antimicrobial susceptibility (AMS) pattern of aerobes in DFIs.

METHODS

A cross-sectional study was conducted for a period of 3 years at Department of Surgery, Kasturba hospital, Manipal, India during which, 260 diabetic foot ulcer (DFU) patients admitted in the general surgery wards were enrolled for the study. These patients' culture specimens were observed as Gram-stained smears and cultured aerobically on blood agar and MacConkey agar plates. AMS test was performed by disc diffusion technique according to Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

A total of 354 microbes were isolated from the ulcer wounds of 213 diabetic foot patients, with an average of 1.7 organisms per lesion. Monomicrobial infections were less common (n=81; 31.2%) than polymicrobial infections (n=132; 50.7%). Gram-negative bacteria were the most common among the isolates (n=192; 54.2%). Aerobic Gram-positive Cocci accounted for 162 (45.8%) of all isolates. On the other hand, Staphylococcus aureus was the most frequently isolated aerobe (n=106; 29.9%) followed by Pseudomonas aeruginosa (n=91; 25.7%).

CONCLUSION

AMS data from our study recommends that doxycycline would be the appropriate choice as single drug for empirical coverage for Gram-positive organisms. The most appropriate antibiotic for Gram-negative organisms is meropenem. One of the critical observations is the presence of Acinetobacter, an MDR isolated from DFIs, which is either relatively or totally resistant to all the AMAs tested.

Bacteriophage ZCKP1: A Potential Treatment for Klebsiella pneumoniae Isolated From Diabetic Foot Patients

The recorded growth in infection by multidrug resistant bacteria necessitates prompt efforts toward developing alternatives to antibiotics, such as bacteriophage therapy. Immuno-compromised patients with diabetes mellitus are particularly prone to foot infections by multidrug resistant Klebsiella pneumoniae, which may be compounded by chronic osteomyelitis. Bacteriophage ZCKP1, isolated from freshwater in Giza, Egypt, was tested in vitro to evaluate its lytic activity against a multidrug resistant K. pneumoniae KP/01, isolated from foot wound of a diabetic patient in Egypt. Characterization of ZCKP1 phage indicated that it belonged to the Myoviridae family of bacteriophages with a ds-DNA genome size of 150.9 kb. Bacteriophage ZCKP1 lysed a range of osteomyelitis pathogenic agents including Klebsiella spp., Proteus spp. and E. coli isolates. The bacteriophage reduced the bacterial counts of host bacteria by ≥2 log₁₀ CFU/ml at 25°C, and demonstrated the ability to reduce bacterial counts and biofilm biomass (>50%) when applied at high multiplicity of infection (50 PFU/CFU). These characteristics make ZCKP1 phage of potential therapeutic value to treat K. pneumoniae and associated bacteria present in diabetic foot patients.