Systemic antibiotics for treating diabetic foot infections

A systematic review and meta-analysis of randomized controlled trials of systemic antibiotics for diabetes-related foot infections

OBJECTIVE

Diabetes-related foot infections (DFIs) are prevalent in patients with diabetes mellitus, often leading to severe complications, including amputations. This study aims to assess the efficacy and safety of systemic antibiotics in DFI treatment.

RESEARCH DESIGN AND METHODS

A systematic review was conducted by searching PubMed, Cochrane databases, and Embase for randomized controlled trials up to August 4, 2024, evaluating the clinical efficacy of systemic antibiotics for DFIs. Primary outcomes were clinical efficacy and safety, comparing different antibiotic classes to penicillins. Subgroup analysis was based on DFI severity.

RESULTS

Of 24 studies, 16 were included in the meta-analysis. Linezolid showed a potential efficacy advantage over penicillins for DFIs but had more adverse effects. Clinical efficacy and safety were comparable across carbapenems and quinolones versus penicillins. Ertapenem showed no significant difference from piperacillin/tazobactam in treating moderate or severe DFIs.

CONCLUSION

In conclusion, while linezolid may offer a potential efficacy advantage over penicillins in treating DFIs, it is associated with a higher risk of drug-related adverse effects. Penicillins demonstrate comparable clinical efficacy and safety to carbapenems and fluoroquinolones for DFI management. For moderate to severe DFIs, piperacillin/tazobactam and ertapenem are viable options, though treatment should be guided by local antimicrobial resistance patterns.

Deciphering Diabetic Foot Wounds: A Comprehensive Review on Classification, Multidrug Resistance, Microbial Insights, Management & Treatment Strategies, and Advanced Diagnostic Tools

Diabetic foot wounds and infections pose a significant and evolving challenge in diabetes care. Diabetic wound healing has become a major global concern for a very long time. Continuous research has been conducted to increase the healing process in diabetic ulcers to the rate of amputation. Wound healing is prolonged in diabetic patients due to various conditions, such as high glucose levels, neuropathy, poor blood circulation, and prolonged inflammation around the limbs, which causes the healing to be delayed compared to normal patients. Understanding the complexity of chronic foot wounds and the management and proper treatment would lead to a decrease in the risk of amputation. The medical team all over the world is constantly researching to lower the risk. This review paper offers a compelling journey through the multifaceted world of diabetic foot wounds and infections. It underscores the urgency of understanding classification, tackling multidrug resistance, and harnessing microbial insights to revolutionize the treatment and management of diabetic foot complications. Furthermore, it unveils state-of-the-art diagnostics, heralding a brighter future in the battle against this debilitating complication of diabetes.

Preoperative Antibiotic Administration Does Not Improve the Outcomes of Operated Diabetic Foot Infections

Many patients with community-acquired diabetic foot infections (DFI) receive systemic (empirical) antibiotic treatments before surgical interventions, often by the general practitioner. Sometimes, hospital clinicians prescribe them before surgery to reduce the infection inoculum and preserve soft tissue for immediate wound closure in case of residual infection after surgery. In contrast, the international guidelines (IWGDF) advocate against presurgical antibiotic use in routine situations without severe progredient soft tissue infections and/or sepsis. We run several retrospective and prospective cohorts of DFI and retrospectively analyze the influence of presurgical antibiotic therapy (as binary (yes/no) or continuous (in days) variables) on failures after a combined surgical and medical treatment. In our large database, the presence, choice, administration routes, or duration of preoperative antibiotic therapy did not improve the postoperative outcomes of operated diabetic foot infections or prevent their failures. In turn, this lack of influence leaves space for enhanced antibiotic stewardship in the management of DFI.

Risk factors related to amputation in diabetic foot patients: single center outcomes

AIM

This study aimed at identifying factors that worsen the prognosis of diabetic foot, one of the most common complications seen in patients with diabetes.

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.

Does PAD and microcirculation status impact the tissue availability of intravenously administered antibiotics in patients with infected diabetic foot? Results of the DFIATIM substudy

Aims/hypothesis

The aim of this substudy (Eudra CT No:2019-001997-27)was to assess ATB availability in patients with infected diabetic foot ulcers(IDFUs)in the context of microcirculation and macrocirculation status.

Methods

For this substudy, we enrolled 23 patients with IDFU. Patients were treated with boluses of amoxicillin/clavulanic acid(AMC)(12patients) or ceftazidime(CTZ)(11patients). After induction of a steady ATB state, microdialysis was performed near the IDFU. Tissue fluid samples from the foot and blood samples from peripheral blood were taken within 6 hours. ATB potential efficacy was assessed by evaluating the maximum serum and tissue ATB concentrations(Cmax and Cmax-tissue)and the percentage of time the unbound drug tissue concentration exceeds the minimum inhibitory concentration (MIC)(≥100% tissue and ≥50%/60% tissue fT>MIC). Vascular status was assessed by triplex ultrasound, ankle-brachial and toe-brachial index tests, occlusive plethysmography comprising two arterial flow phases, and transcutaneous oxygen pressure(TcPO2).

Results

Following bolus administration, the Cmax of AMC was 91.8 ± 52.5 μgmL-1 and the Cmax-tissue of AMC was 7.25 ± 4.5 μgmL-1(P<0.001). The Cmax for CTZ was 186.8 ± 44.1 μgmL-1 and the Cmax-tissue of CTZ was 18.6 ± 7.4 μgmL-1(P<0.0001). Additionally, 67% of patients treated with AMC and 55% of those treated with CTZ achieved tissue fT>MIC levels exceeding 50% and 60%, respectively. We observed positive correlations between both Cmax-tissue and AUCtissue and arterial flow. Specifically, the correlation coefficient for the first phase was r=0.42; (P=0.045), and for the second phase, it was r=0.55(P=0.01)and r=0.5(P=0.021).

Conclusions

Bactericidal activity proved satisfactory in only half to two-thirds of patients with IDFUs, an outcome that appears to correlate primarily with arterial flow.

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.

Evaluation of the Use of Antimicrobial Therapy for Treating Diabetic Foot Infections in an Indonesia Referral Hospital: A Retrospective Cohort Study

BACKGROUND

Diabetic foot infection (DFI) is a common complication of hyperglycemia and is related to prolongation of hospitalization, mortality, high hospitalization costs and decreased quality of life. Antibiotic therapy is one of the most critical factors in the eradication of infection. This study aims to determine the appropriateness of antibiotic use based on the local and international clinical guidelines and its short-term effect on patients' clinical improvement.

MATERIALS AND METHODS

This retrospective cohort study was conducted using secondary data from DFI inpatients from 1 January 2018 to 31 May 2020, from Dr. Cipto Mangunkusumo Hospital (RSCM), the National Referral Hospital of Indonesia. The Gyssens algorithm was used to help assess the appropriateness of antibiotics. All subjects were type 2 Diabetes Mellitus (T2DM) adult patients diagnosed with DFI. The primary outcome was a clinical improvement of infection after 7 - 14 days of antibiotic use. The clinical improvement of infection was defined by a minimum of three of these criteria: reduced or no purulent secretions, no fever, the area around the wound did not feel warm, no or reduced local oedema, no local pain, reduced redness or erythema, and decreased leukocytes count.

RESULTS

A total of 113 (63.5%) eligible subjects from a total of 178 were recruited. Among the patients, 51.4% had a duration of T2DM for ≥10 years, 60.2% had uncontrolled hyperglycemia, 94.7% had a history of complications, 22.1% had a history of amputation, and 72.6% had ulcer grade ≥3. Based on the Gyssens algorithm, 54.0% of the subjects were given antibiotics appropriately, while the other 46.0% were not. The proportion of improved patients in the appropriate antibiotics group was higher but not statistically significant than those in the inappropriate group (60.7% vs. 42.3%, P = 0.079). However, the results of the multivariate analysis demonstrated that the appropriate use of antibiotics would increase clinical improvement by 2.6 times, compared to inappropriate use after controlling for the covariates (adjusted odds ratio: 2.616, 95% confidence interval: 1.117 - 6.126, P = 0.027).

CONCLUSION

Only half of the patients with DFI received appropriate antibiotics, although an appropriate antibiotics usage was independently associated with better short-term clinical improvement in DFI. This suggests that we should effort to improve appropriateness in antibiotics usage in DFI.

2-Octylcyclopentanone Inhibits Beta Lactam Resistant Diabetic Wound Pathogens

Microbial infection is a frequent complication of diabetic foot ulcers, with up to 82% of ulcers being infected at the initial stage of diabetes. Furthermore, the emergence of beta lactam resistant pathogens managed to eliminate the use of beta lactam antibiotics as a chemotherapeutic alternative. This further increases the amputation and mortality rate. Hence, the aim of this study is to evaluate antimicrobial efficacy of a ketone derivative 2-octylcyclopentanone against diabetic wound pathogens. The inhibitory activity of the compound was determined using disc diffusion and broth microdilution assay. Generally, 2-octylcyclopentanone showed broad-spectrum antimicrobial activity, particularly against beta lactam resistant pathogens. The compound showed comparably better antimicrobial activity than all reference antibiotics, including chloramphenicol, streptomycin, ampicillin and penicillin. In addition, the same compound also inhibits a clinically isolated Pseudonomas aeruginosa that was resistant to all reference antibiotics. The activity was microbicidal based on the low minimal lethality concentration recorded, particularly on MRSA, P. aeruginosa and Candida utilis. The killing efficiency of the compound was concentration dependent. During kill curve analysis, the inhibitory activity of 2-octylcyclopentanone was concentration and time-dependent. 99.9% of reduction of bacterial growth was observed. MRSA and P. aeruginosa, two significant diabetic wound infections, are totally inhibited by the molecule at a concentration of minimum lethality concentration. In short, 2-octylcyclopentanone exhibited significant inhibitory towards wide range of diabetic wound pathogens. Which is considered crucial since it will provide a safe and effective alternative treatment for diabetic ulcer infection.

The Role of Novel Antibiotics in the Management of Diabetic Foot Infection

Diabetic foot infection is a frequent and potentially life-threatening complication of diabetes mellitus. Antibiotic treatment is the cornerstone of management of diabetic foot infection but the rising prevalence of antibiotic resistance has resulted in increasing rates of treatment failure. In this context, the development of several novel antibiotics might represent a useful tool in severe diabetic foot infections caused by multidrug-resistant bacteria. In the present review, we summarize the safety and efficacy of novel antibiotics in patients with diabetic foot infection. Relevant data are limited, and randomized controlled studies that evaluated the role of these agents in this field are lacking. Until more robust data are available, cefiderocol and dalbavancin, which have been studied more extensively in patients with bone infections, might be attractive options in carefully selected patients with severe diabetic foot infection.

Short and oral antimicrobial therapy for diabetic foot infection: a narrative review of current knowledge

Diabetic foot infection is a frequent complication in long-standing diabetes mellitus. For antimicrobial therapy of this infection, both the optimal duration and the route of administration are often based more on expert opinion than on published evidence. We reviewed the scientific literature, specifically seeking prospective trials, and aimed at addressing two clinical issues: (1) shortening the currently recommended antibiotic duration and (2) using oral (rather than parenteral) therapy, especially after the patient has undergone debridement and revascularization. We also reviewed some older key articles that are critical to our understanding of the treatment of these infections, particularly with respect to diabetic foot osteomyelitis. Our conclusion is that the maximum duration of antibiotic therapy for osteomyelitis should be no more than to 4-6 weeks and might even be shorter in selected cases. In the future, in addition to conducting randomized trials and propagating national and international guidance, we should also explore innovative strategies, such as intraosseous antibiotic agents and bacteriophages.

Opinions about the most appropriate surgical management of diabetes-related foot infection: a cross-sectional survey

Background

There is a lack of high quality evidence to guide the optimal management of diabetes-related foot infection, particularly in cases of severe diabetes-related foot infection and diabetes-related foot osteomyelitis. This study examined the opinions of surgeons about the preferred management of severe diabetes-related foot infection.

Methods

Vascular and orthopaedic surgeons in Australia and New Zealand were invited to complete an online survey via email. The survey included multi-choice and open-ended questions on clinical management of diabetes-related foot infection. Responses of vascular surgeons and orthopaedic surgeons were compared using non-parametric statistical tests. Open-text responses were examined using inductive content analysis.

Results

29 vascular and 20 orthopaedic surgeons completed the survey. One-third (28.6%) used best-practice guidelines to assist in decisions about foot infection management. Areas for guideline improvement identified included more specific advice regarding the indications for available treatments, more recommendations about non-surgical patient management and advice on how management can be varied in regions with limited health service resource. The probe-to-bone test and magnetic resonance imaging were the preferred methods of diagnosing osteomyelitis. Approximately half (51.2%) of respondents indicated piperacillin combined with tazobactam as the preferred antibiotic choice for empirical treatment of severe diabetes-related foot infection. Negative pressure wound therapy was the most common way of managing a wound following debridement. All vascular surgeons (100%) made revascularisation decisions based on the severity of ischemia while most orthopaedic surgeons (66.7%) were likely to refer to vascular surgeons to make revascularisation decisions. Vascular surgeons preferred using wound swabs while orthopaedic surgeons favoured tissue or bone biopsies to determine the choice of antibiotic. Respondents perceived a moderate variation in management decisions between specialists and supported the need for randomised controlled trials to test different management pathways.

Conclusions

Most vascular and orthopaedic surgeons do not use best-practice guidelines to assist in decisions about management of diabetes-related foot infection. Vascular and orthopaedic surgeons appear to have different preferences for wound sampling to determine choice of antibiotic. There is a need for higher quality evidence to clarify best practice for managing diabetes-related foot infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00523-w.

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.

The Effects of Antimicrobial Resistance and the Compatibility of Initial Antibiotic Treatment on Clinical Outcomes in Patients With Diabetic Foot Infection

We aimed to determine pathogen microorganisms, their antimicrobial resistance patterns, and the effect of initial treatment on clinical outcomes in patients with diabetic foot infection (DFI). Patients with DFI from 5 centers were included in this multicenter observational prospective study between June 2018 and June 2019. Multivariate analysis was performed for the predictors of reinfection/death and major amputation. A total of 284 patients were recorded. Of whom, 193 (68%) were male and the median age was 59.9 ± 11.3 years. One hundred nineteen (41.9%) patients had amputations, as the minor (n = 83, 29.2%) or major (n = 36, 12.7%). The mortality rate was 1.7% with 4 deaths. A total of 247 microorganisms were isolated from 200 patients. The most common microorganisms were Staphylococcus aureus (n = 36, 14.6%) and Escherichia coli (n = 32, 13.0%). Methicillin resistance rates were 19.4% and 69.6% in S aureus and coagulase-negative Staphylococcus spp., respectively. Multidrug-resistant Pseudomonas aeruginosa was detected in 4 of 22 (18.2%) isolates. Extended-spectrum beta-lactamase-producing Gram-negative bacteria were detected in 20 (38.5%) isolates of E coli (14 of 32) and Klebsiella spp. (6 of 20). When the initial treatment was inappropriate, Klebsiella spp. related reinfection within 1 to 3 months was observed more frequently. Polymicrobial infection (p = .043) and vancomycin treatment (p = .007) were independent predictors of reinfection/death. Multivariate analysis revealed vascular insufficiency (p = .004), hospital readmission (p = .009), C-reactive protein > 130 mg/dL (p = .007), and receiving carbapenems (p = .005) as independent predictors of major amputation. Our results justify the importance of using appropriate narrow-spectrum empirical antimicrobials because higher rates of reinfection and major amputation were found even in the use of broad-spectrum antimicrobials.

Physician Responsiveness to Positive Blood Culture Results at the Minneapolis Veterans Affairs Hospital-Is Anyone Paying Attention?

Background

Patients presenting with suspected infections are typically placed on empiric broad-spectrum antibiotics. With mounting evidence supporting the efficacy of using the narrowest spectrum of antimicrobial therapy to cover the suspected pathogen, current guidelines recommend decreasing the breadth of coverage in response to culture results both in relation to microbe identification and antibiotic sensitivity.

Methods

A retrospective chart review of electronic health records at the Minneapolis Veterans Affairs Medical Center (VAMC) in Minnesota was performed for 208 positive blood cultures with antibiotic spectrum analysis from July 1, 2015 to June 30, 2016. The time of reporting for pathogen identification and subsequent pathogen susceptibilities were compared to the time at which any alterations to antibiotic coverage were made. The breadth of antibiotic coverage was recorded using a nonlinear spectrum score. The use of this score allowed for the reliable classification of antibiotic adjustments as either deescalation, escalation, or no change.

Results

The percentage of cases deescalated was higher in response to physician (house staff or attending physician) notification of pathogen susceptibility information when compared with a response to pathogen identification alone (33.2% vs 22.6%). Empiric antibiotics were not altered within 24 hours in response to pathogen identification in 70.7% of cases and were not altered within 24 hours in response to pathogen sensitivity determination in 58.6% of cases. However, when considering the time frame from when empiric antibiotics were started to 24 hours after notification of susceptibility information, 49.5% of cases were deescalated and 41.5% of cases had no net change in the antibiotic spectrum score. The magnitude of deescalations were notably larger than escalations. The mean (SD) time to deescalation of antibiotic coverage was shorter (P =.049) in response to pathogen identification at 8 (7.4) hours compared with sensitivity information at 10.4 (7) hours, but may not be clinically relevant.

Conclusion

Health care providers at the Minneapolis VAMC appear to be using positive blood culture results in a timely fashion consistent with best practices. Because empirically initiated antibiotics typically are broad in spectrum, the magnitude of deescalations were notably larger than escalations. Adherence to these standards may be a reflection of the infectious disease staff oversight of antibiotic administration. Furthermore, the systems outlined in this quality improvement study may be replicated at other VAMCs across the country by either in-house infectious disease staff or through remote monitoring of the electronic health record by other infectious disease experts at a more centralized VAMC. Widespread adoption throughout the Veterans Health Administration may result in improved antibiotic resistance profiles and better clinical outcomes for our nation's veterans.

Multidrug-resistant bacteria in diabetic foot infections: Experience from a portuguese tertiary centre

In recent years, the emergence of antibiotic resistant pathogens made increasingly difficult to establish appropriate empiric antimicrobial therapy protocols for acute diabetic foot infection (DFI) treatment. Early recognition of the population at-risk for multidrug-resistant (MDR) bacterial infection is of paramount importance in order to decrease large-spectrum antibiotic overuse. This study used retrospective cohort study in a multidisciplinary tertiary diabetic foot unit. Patients with severe DFI were included and divided according to their infection resistance profile (susceptible vs MDR bacteria). Data regarding their comorbidities and length of hospital stay were collected. The primary endpoint was to determine the risk factors for MDR infections and to evaluate if these were associated with an increased length of stay (LOS). A total of 112 microbial isolates were included. Predominance of Gram-positive bacteria was observed and 22.3% of isolated bacteria were MDR. Previous hospitalisation was associated with a higher likelihood of MDR infection. MDR bacterial infection was also associated with an increased LOS (P = .0296). Our study showed a high incidence of MDR bacteria in patients with a DFI, especially in those who had a recent hospitalisation. MDR infections were associated with a prolonged LOS and represent a global public health issue for which emergent measures are needed.

Determination of antimicrobial effect of protamine by transmission electron microscopy and SDS PAGE on Pseudomonas aeruginosa isolates from diabetic foot infection

Objective(s):

Diabetic foot infection is one of the major complications of diabetes leading to lower limb amputations. Isolation and identification of bacteria causing diabetic foot infection, determination of antibiotic resistance, antimicrobial potential of protamine by electron microscopy and SDS-PAGE analysis, arethe aims of this study.

Materials and Methods:

285 pus samples from diabetic foot infection patients were collected from different hospitals of Karachi and Capital Health Hospital, Halifax, Canada. Clinical history of each patient was recorded. Bacterial isolates were cultured on appropriate media; identification was done by morphology, cultural and biochemical tests. Effect of protamine against multi drug resistant strains of Pseudomona aeruginosa was checked by minimum inhibitory concentration in 96 well micro-titer plates. The isolates were grown in bactericidal concentration of protamine on plates to isolate mutants. Effect of protamine on protein expression was checked by SDS- PAGE and ultra-structural morphological changes by transmission electron microscopy.

Results:

Results indicated prevalence of foot infection as 92% in diabetic patients. Major bacterial isolates were Staphylococcus aureus 65 (23%), P. aeruginosa 80 (28.1%), Klebsiella spp. 37 (13%), Proteus mirabilis 79 (27.7%), and Escherichia coli 24 (12%). These isolates were highly resistant to different antibiotics. MIC value of protamine was 500 µg/ml against P. aeruginosa. SDS-PAGE analysis revealed that protamine can suppress expression of various virulence proteins and electron micrographs indicated condensation of cytoplasm and accumulation of protamine in cytoplasm without damaging the cell membrane.

Conclusion:

P. aeruginosa and S. aureus were the major isolates expressing multi-drug resistance and protamine sulfate represented good antimicrobial potential.

Evaluation of mortality risk factors in diabetic foot infections

Identifying risk factors for mortality is crucial in the management of diabetic foot syndrome. We aimed to evaluate risk factors for mortality in patients with diabetic foot infection (DFI). A retrospective chart review was conducted on 401 patients from 2010 through 2019. Our primary endpoint was in-hospital mortality. Patients were divided into two groups according to the outcome (survival or death). Clinical data were compared between the two groups statistically. A total of 401 patients were enrolled in the study, 280 (69.8%) of them were male and the mean age was 59.6 ± 11.1 years. The mean follow-up period was 23.7 ± 22.9 months. In-hospital mortality rate was 3%. Univariate analysis indicated that ischaemic wound (P = .023), hindfoot infection (P = .038), whole foot infection (P = .010), peripheral arterial disease (P = .024), high leucocyte levels (>12 040 K/μL) (P = .001), high thrombocyte levels (>378 000 K/μL) (P < 0.001), high C-reactive protein levels (>8.81 mg/dL) (P = .022), and polymicrobial growth in deep tissue culture (P = .041) were significant parameters in predicting mortality. In multivariate analysis, peripheral arterial disease (odds ratio [OR]: 13.430, 95% confidence interval [Cl]: 1.129-59.692; P = .040), high thrombocyte levels (OR: 1.000, 95% Cl: 1.000-1.000; P = .022), and polymicrobial growth in deep tissue culture (OR: 7.790, 95% Cl: 1.592-38.118; P = .011) were independent risk factors for mortality. In conclusion, peripheral arterial disease, high thrombocyte levels, and polymicrobial growth in deep tissue culture were independent risk factors for mortality in DFI.

Susceptibility of monomicrobial or polymicrobial biofilms derived from infected diabetic foot ulcers to topical or systemic antibiotics in vitro

Diabetic foot ulcers can become chronic and non-healing despite systemic antibiotic treatment. The penetration of systematically-administered antibiotics to the site of infection is uncertain, as is the effectiveness of such levels against polymicrobial biofilms. We have developed an in vitro model to study the effectiveness of different treatments for infected diabetic foot ulcers in a wound-like environment and compared the activity of systemic levels of antibiotics with that for topically applied antibiotics released from calcium sulfate beads. This is the first study that has harvested bacteria from diabetic foot infections and recreated similar polymicrobial biofilms to those present in vivo for individual subjects. After treatment with levels of gentamicin attained in serum after systemic administration (higher than corresponding tissues concentrations) we measured a 0-2 log reduction in bacterial viability of P. aeruginosa, S. aureus or a polymicrobial biofilm. Conversely, addition of gentamicin loaded calcium sulfate beads resulted in 5-9 log reductions in P. aeruginosa, S aureus and polymicrobial biofilms derived from three subjects. We conclude that systemically administered antibiotics are likely to be inadequate for successfully treating these infections, especially given the vastly increased concentrations required to inhibit cells in a biofilm, and that topical antibiotics provide a more effective alternative.

Diabetic Foot Infection: Causative Pathogens and Empiric Antibiotherapy Considerations—The Experience of a Tertiary Center

Most moderate-to-severe diabetic foot infections (DFIs) require hospitalization with urgent surgical approach and administration of empiric antibiotherapy. To ensure optimal antibiotic coverage, regular microbiological background updates are imperative. The purpose is to characterize the microbiological profile and the antibiotic sensitivity pattern of the DFI causative pathogens isolated within a specialized DFI unit of a tertiary hospital, in order to establish evidence-based policies regarding empirical antibiotic use. A cross-sectional study was conducted. Microbiological cultures and corresponding antibiotic sensitivity tests collected from moderate-to-severe DFIs as a first approach to the hospitalized patient were retrieved and analyzed during a 12-month period. Two groups were analyzed: inpatients that had been previously followed at the diabetic foot clinic of the hospital and inpatients without a previous contact with the hospital services. A total of 125 isolates obtained from 87 patients were deemed for analysis. Globally, a predominance of Gram-positive bacteria was observed (60%). Staphylococcus aureus was the most common pathogen. The global ratio of methicillin-sensitive S aureus to methicillin-resistant S aureus (MRSA) was 1.3:1, with similar findings in both groups. According to the antibiotic sensitivity test results, and within the recommended empiric antibiotic regimens for DFI, piperacillin/tazobactam seems to be the most suitable option. Gram-positive bacteria prevail as the main isolates in DFIs. Screening for MRSA-specific risk factors is mandatory. When going for a first empiric therapy, piperacillin/tazobactam is recommended in this institution, and an anti-MRSA agent should be added early, if necessary. We encourage continuous monitoring for the bacterial prevalence in Portuguese diabetic foot centers as it is paramount for the decision making regarding DFI protocols.

Diabetic Foot Infections: Update on Management

PURPOSE OF REVIEW

Diabetic foot infections (DFIs) are common in patients with diabetes mellitus complicated by foot ulcers and can be classified in different categories based on their severity. In this report, we present the diagnosis and management of DFIs according to their classification.

RECENT FINDINGS

While appropriate antibiotic regiments and surgical techniques for the treatment of DFIs are well established, new technologies and techniques for example in medical imaging, wound care modalities, and supplementary therapy approaches show potentially promising results in preventing DFIs. As with every complex disease, fine tuning DFI management can be challenging as it requires careful evaluation of different parameters. It demands timely action, close collaboration of different specialties, and patient cooperation.

Models Used in Clinical Decision Support Systems Supporting Healthcare Professionals Treating Chronic Wounds: Systematic Literature Review

Background

Chronic wounds such as diabetic foot ulcers, venous leg ulcers, and pressure ulcers are a massive burden to health care facilities. Many randomized controlled trials on different wound care elements have been conducted and published in the Cochrane Library, all of which have only a low evidential basis. Thus, health care professionals are forced to rely on their own experience when making decisions regarding wound care. To progress from experience-based practice to evidence-based wound care practice, clinical decision support systems (CDSS) that help health care providers with decision-making in a clinical workflow have been developed. These systems have proven useful in many areas of the health care sector, partly because they have increased the quality of care, and partially because they have generated a solid basis for evidence-based practice. However, no systematic reviews focus on CDSS within the field of wound care to chronic wounds.

Objective

The aims of this systematic literature review are (1) to identify models used in CDSS that support health care professionals treating chronic wounds, and (2) to classify each clinical decision support model according to selected variables and to create an overview.

Methods

A systematic review was conducted using 6 databases. This systematic literature review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement for systematic reviews. The search strategy consisted of three facets, respectively: Facet 1 (Algorithm), Facet 2 (Wound care) and Facet 3 (Clinical decision support system). Studies based on acute wounds or trauma were excluded. Similarly, studies that presented guidelines, protocols and instructions were excluded, since they do not require progression along an active chain of reasoning from the clinicians, just their focus. Finally, studies were excluded if they had not undergone a peer review process. The following aspects were extracted from each article: authors, year, country, the sample size of data and variables describing the type of clinical decision support models. The decision support models were classified in 2 ways: quantitative decision support models, and qualitative decision support models.

Results

The final number of studies included in the systematic literature review was 10. These clinical decision support models included 4/10 (40%) quantitative decision support models and 6/10 (60%) qualitative decision support models. The earliest article was published in 2007, and the most recent was from 2015.

Conclusions

The clinical decision support models were targeted at a variety of different types of chronic wounds. The degree of accessibility of the inference engines varied. Quantitative models served as the engine and were invisible to the health care professionals, while qualitative models required interaction with the user.

Microbiology and Antimicrobial Therapy for Diabetic Foot Infections

In addition to being the prime factor associated with amputation, diabetic foot infections (DFIs) are associated with major morbidity, increasing mortality, and reduced quality of life. The choice of appropriate antibiotics is very important in order to reduce treatment failure, antimicrobial resistance, adverse events, and costs. We reviewed articles on microbiology and antimicrobial therapy and discuss antibiotic selection in Korean patients with DFIs. Similar to Western countries, Staphylococcus aureus is the most common pathogen, with Streptococcus, Enterococcus, Enterobacteriaceae and Pseudomonas also prevalent in Korea. It is recommended that antibiotics are not prescribed for clinically uninfected wounds and that empirical antibiotics be selected based on the clinical features, disease severity, and local antimicrobial resistance patterns. Narrow-spectrum oral antibiotics can be administered for mild infections and broad-spectrum parenteral antibiotics should be administered for some moderate and severe infections. In cases with risk factors for methicillin-resistant S. aureus or Pseudomonas, empirical antibiotics to cover each pathogen should be considered. The Health Insurance Review and Assessment Service standards should also be considered when choosing empirical antibiotics. In Korea, nationwide studies need to be conducted and DFI guidelines should be developed.

Diabetes-related amputations create considerable public health burden in the UK

AIMS

The main aim of this study was to assess the cost of diabetic amputation (both direct and indirect) to the National Health Service from the point of amputation onwards.

METHODS

This systematic review involved searches of published literature between January 2007 and March 2017 mainly using the bibliographic databases, the Cochrane Library, EMBASE via Ovid®, MEDLINE via Ovid®, as well as grey literature, both in print and in electronic formats published through non-commercial publications, which reported the cost of amputation due to diabetic foot ulcers.

RESULTS

The studies included in this review varied considerably in estimating the cost including cost elements and how those costs were categorised. The cost estimates for inpatient care associated with amputation involving admissions or procedures on amputation stumps in people with diabetes was £43.8 million. The annual expenditure for post-amputation care involving prosthetic care, physiotherapy, transport and wheelchair use was £20.8 million.

CONCLUSIONS

There is a considerable public health and economic burden caused by diabetes-related amputations in England. More focussed research is needed with improved methods of estimating costs that would account for direct and indirect costs associated with diabetic amputation.

Topical antimicrobial agents for treating foot ulcers in people with diabetes

BACKGROUND

People with diabetes are at high risk for developing foot ulcers, which often become infected. These wounds, especially when infected, cause substantial morbidity. Wound treatments should aim to alleviate symptoms, promote healing, and avoid adverse outcomes, especially lower extremity amputation. Topical antimicrobial therapy has been used on diabetic foot ulcers, either as a treatment for clinically infected wounds, or to prevent infection in clinically uninfected wounds.

OBJECTIVES

To evaluate the effects of treatment with topical antimicrobial agents on: the resolution of signs and symptoms of infection; the healing of infected diabetic foot ulcers; and preventing infection and improving healing in clinically uninfected diabetic foot ulcers.

SEARCH METHODS

We searched the Cochrane Wounds Specialised Register, CENTRAL, Ovid MEDLINE, Ovid MEDLINE (In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus in August 2016. We also searched clinical trials registries for ongoing and unpublished studies, and checked reference lists to identify additional studies. We used no restrictions with respect to language, date of publication, or study setting.

SELECTION CRITERIA

We included randomised controlled trials conducted in any setting (inpatient or outpatient) that evaluated topical treatment with any type of solid or liquid (e.g., cream, gel, ointment) antimicrobial agent, including antiseptics, antibiotics, and antimicrobial dressings, in people with diabetes mellitus who were diagnosed with an ulcer or open wound of the foot, whether clinically infected or uninfected.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment, and data extraction. Initial disagreements were resolved by discussion, or by including a third review author when necessary.

MAIN RESULTS

We found 22 trials that met our inclusion criteria with a total of over 2310 participants (one study did not report number of participants). The included studies mostly had small numbers of participants (from 4 to 317) and relatively short follow-up periods (4 to 24 weeks). At baseline, six trials included only people with ulcers that were clinically infected; one trial included people with both infected and uninfected ulcers; two trials included people with non-infected ulcers; and the remaining 13 studies did not report infection status.Included studies employed various topical antimicrobial treatments, including antimicrobial dressings (e.g. silver, iodides), super-oxidised aqueous solutions, zinc hyaluronate, silver sulphadiazine, tretinoin, pexiganan cream, and chloramine. We performed the following five comparisons based on the included studies: Antimicrobial dressings compared with non-antimicrobial dressings: Pooled data from five trials with a total of 945 participants suggest (based on the average treatment effect from a random-effects model) that more wounds may heal when treated with an antimicrobial dressing than with a non-antimicrobial dressing: risk ratio (RR) 1.28, 95% confidence interval (CI) 1.12 to 1.45. These results correspond to an additional 119 healing events in the antimicrobial-dressing arm per 1000 participants (95% CI 51 to 191 more). We consider this low-certainty evidence (downgraded twice due to risk of bias). The evidence on adverse events or other outcomes was uncertain (very low-certainty evidence, frequently downgraded due to risk of bias and imprecision). Antimicrobial topical treatments (non dressings) compared with non-antimicrobial topical treatments (non dressings): There were four trials with a total of 132 participants in this comparison that contributed variously to the estimates of outcome data. Evidence was generally of low or very low certainty, and the 95% CIs spanned benefit and harm: proportion of wounds healed RR 2.82 (95% CI 0.56 to 14.23; 112 participants; 3 trials; very low-certainty evidence); achieving resolution of infection RR 1.16 (95% CI 0.54 to 2.51; 40 participants; 1 trial; low-certainty evidence); undergoing surgical resection RR 1.67 (95% CI 0.47 to 5.90; 40 participants; 1 trial; low-certainty evidence); and sustaining an adverse event (no events in either arm; 81 participants; 2 trials; very low-certainty evidence). Comparison of different topical antimicrobial treatments: We included eight studies with a total of 250 participants, but all of the comparisons were different and no data could be appropriately pooled. Reported outcome data were limited and we are uncertain about the relative effects of antimicrobial topical agents for each of our review outcomes for this comparison, that is wound healing, resolution of infection, surgical resection, and adverse events (all very low-certainty evidence). Topical antimicrobials compared with systemic antibiotics : We included four studies with a total of 937 participants. These studies reported no wound-healing data, and the evidence was uncertain for the relative effects on resolution of infection in infected ulcers and surgical resection (very low certainty). On average, there is probably little difference in the risk of adverse events between the compared topical antimicrobial and systemic antibiotics treatments: RR 0.91 (95% CI 0.78 to 1.06; moderate-certainty evidence - downgraded once for inconsistency). Topical antimicrobial agents compared with growth factor: We included one study with 40 participants. The only review-relevant outcome reported was number of ulcers healed, and these data were uncertain (very low-certainty evidence).

AUTHORS' CONCLUSIONS

The randomised controlled trial data on the effectiveness and safety of topical antimicrobial treatments for diabetic foot ulcers is limited by the availability of relatively few, mostly small, and often poorly designed trials. Based on our systematic review and analysis of the literature, we suggest that: 1) use of an antimicrobial dressing instead of a non-antimicrobial dressing may increase the number of diabetic foot ulcers healed over a medium-term follow-up period (low-certainty evidence); and 2) there is probably little difference in the risk of adverse events related to treatment between systemic antibiotics and topical antimicrobial treatments based on the available studies (moderate-certainty evidence). For each of the other outcomes we examined there were either no reported data or the available data left us uncertain as to whether or not there were any differences between the compared treatments. Given the high, and increasing, frequency of diabetic foot wounds, we encourage investigators to undertake properly designed randomised controlled trials in this area to evaluate the effects of topical antimicrobial treatments for both the prevention and the treatment of infection in these wounds and ultimately the effects on wound healing.

Diabetic foot infections: Current treatment and delaying the 'post-antibiotic era'

BACKGROUND

Treatment for diabetic foot infections requires properly diagnosing infection, obtaining an appropriate specimen for culture, assessing for any needed surgical procedures and selecting an empiric antibiotic regimen. Therapy will often need to be modified based on results of culture and sensitivity testing. Because of excessive and inappropriate use of antibiotics for treating diabetic foot infections, resistance to the usually employed bacteria has been increasing to alarming levels.

REVIEW

This article reviews recommendations from evidence-based guidelines, informed by results of systematic reviews, on treating diabetic foot infections. Data from the pre-antibiotic era reported rates of mortality of about 9% and of high-level leg amputations of about 70%. Outcomes have greatly improved with appropriate antibiotic therapy. While there are now many oral and parenteral antibiotic agents that have demonstrated efficacy in treating diabetic foot infections, the rate of infection with multidrug-resistant pathogens is growing. This problem requires a multi-focal approach, including providing education to both clinicians and patients, developing robust antimicrobial stewardship programmes and using new diagnostic and therapeutic technologies. Recently, new methods have been developed to find novel antibiotic agents and to resurrect old treatments, like bacteriophages, for treating these difficult infections.

CONCLUSION

Medical and political leaders have recognized the serious global threat posed by the growing problem of antibiotic resistance. By a multipronged approach that includes exerting administrative pressure on clinicians to do the right thing, investing in new technologies and encouraging the profitable development of new antimicrobials, we may be able to stave off the coming 'post-antibiotic era'.