Oral antimicrobial therapy for diabetic foot osteomyelitis

Diabetic Foot Osteomyelitis in Patients with and without Peripheral Arterial Disease: Two Different Diseases?

The aim of the current study was to evaluate the outcomes of patients with diabetic foot osteomyelitis (DFO), comparing subjects with and without peripheral arterial disease (PAD). The study is a prospective study including a population of patients affected by a DFO located in the forefoot. All patients were managed by a surgical conservative approach defined by the removal of the infected bone, in association with the antibiotic therapy. Patients were divided into two groups: those with PAD (neuro-ischaemic DFO) and those without (neuropathic DFO). After 1 year of follow-up, the following outcome were evaluated and compared between groups: healing, healing time, minor amputation, major amputation, hospitalization, need for surgical re-intervention. Overall, 166 patients were included, 87(52.4%) of them had neuro-ischaemic DFO and 79 (47.6%) neuropathic DFO. Patients with neuro-ischaemic DFO in comparison to neuropathic DFO were older (72.5 ± 9 vs 64.1 ± 15.5 years, P < .0001), had longer diabetes duration (21.8 ± 5.6 vs 16.4 ± 7.6 years, P < .0001), higher rate of dialysis (13.8 vs 1.3%, P = .001) and ischaemic heart disease (79.3 vs 12.7%, P < .0001). Outcomes for neuro-ischaemic DFO and neuropathic DFO were: healing (96.5 vs 97.5%, P = .7), healing time (7.8 ± 6.2 vs 5.7 ± 3.7 weeks, P = .01), minor amputation (16.1 vs 3.8%, P = .006), major amputation (0 vs 0%, ns), hospitalization (90.8 vs 51.9%, P < .0001), surgical re-intervention (14.9 vs 8.8%, P = .004) respectively. In addition, PAD resulted in an independent predictor of minor amputation, hospitalization, and surgical re-intervention. DFO in patients with PAD was characterized by longer healing time, more cases of minor amputation, hospitalization, and surgical re-intervention. PAD independently predicted the risk of minor amputation, hospitalization, and surgical re-intervention, while it was not associated with the healing rate.

MRSA infection, re-infection and clinical outcomes in diabetic foot infections

The aim was to investigate methicillin-resistant Staphylococcus aureus (MRSA) incidence, conversion and outcomes in diabetic foot infections (DFIs). This is a pooled patient-level analysis of combined data sets from two randomised clinical trials including 219 patients admitted to the hospital with moderate or severe DFIs. Intraoperative bone and tissue cultures identified bacterial pathogens. We identified pathogens at index infections and subsequent re-infections. We identified MRSA conversion (MSSA to MRSA) in re-infections. MRSA incidence in index infections was 10.5%, with no difference between soft tissue infections (STIs) and osteomyelitis (OM). MRSA conversion occurred in 7.7% of the re-infections in patients who initially had MSSA in their cultures. Patients with re-infection were 2.2 times more likely to have MRSA compared to the first infection (10.5% vs. 25.8%, relative risk [RR] = 2.2, p = 0.001). Patients with MRSA had longer antibiotic treatment during the 1-year follow-up, compared to other pathogens (other 49.8 ± 34.7 days, MRSA 65.3 ± 41.5 days, p = 0.04). Furthermore, there were no differences in healing, time to heal, length of stay, re-infection, amputation, re-ulceration, re-admission, surgery after discharge and amputation after discharge compared to other pathogens. The incidence of MRSA at the index was 10.5% with no difference in STI and OM. MRSA incidence was 25.8% in re-infections. The RR of having MRSA was 2.2 times higher in re-infections. Patients with MRSA used more antibiotics during the 1-year follow-up. Furthermore, there were no differences in clinical outcomes compared to other bacterial pathogens.

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

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

A Review of the Clinical Utilization of Oral Antibacterial Therapy in the Treatment of Bone Infections in Adults

Chronic osteomyelitis in adults is managed with prolonged courses of intravenous antibiotics in conjunction with surgical debridement of necrotic bone. Over the past 40 years, there has been no paradigm shift in this approach, as randomized controlled trials of this standard of care compared to alternatives such as prolonged oral antibiotics are scarce. However, there have been many small trials, case reports, and review papers evaluating the effectiveness of oral treatment for chronic osteomyelitis. The oral route for infections requiring prolonged treatment is intuitively and practically more favorable due to several advantages, the most important of which is the avoidance of long-term IV antimicrobial therapy with its complications, inconvenience, and cost. In this paper, we review the literature evaluating oral antibiotic therapy in the management of chronic bone infections since 1975. The majority of osteomyelitis infections are caused by Staphylococcus aureus, hence we focus on its treatment using oral antibiotics; however, we also emphasize subpopulations of patients with diabetes, implanted hardware, and with less common bacterial organisms. The primary objective of this review is to promulgate clinical recommendations on the use of oral antibiotics in bone infections in the context of initial therapy, transition from intravenous therapy, and the role of chronic suppression. The secondary objective is to summarize current knowledge of the specific oral antimicrobial agents that are commonly utilized, together with a synopsis of the available literature pertaining to their pharmacokinetic/pharmacodynamic properties and duration of therapy in bone infection.

Do Anti-Biofilm Antibiotics Have a Place in the Treatment of Diabetic Foot Osteomyelitis?

The choice of antibiotic regimens for use in patients presenting with diabetic foot osteomyelitis and their duration differs according to the situation. Antibiotics play a more important role in the medical option where no infected bone has been resected, while their role is reduced but not negligible in the case of surgical options. Some studies have reported the presence of biofilm structures in bone samples taken from patients with diabetic foot osteomyelitis, which raises the question of the place of anti-biofilm antibiotic regimens in this setting. During the last two decades, clinical studies have suggested a potential benefit for anti-biofilm antibiotics, mainly rifampicin against staphylococci and fluoroquinolones against gram-negative bacilli. However, no data from randomized controlled studies have been reported so far. The present work provides a summary of the available data on the question of the place of anti-biofilm antibiotics for the treatment of diabetic foot osteomyelitis, but also the potential limitations of such treatments.

More Specialties, Fewer Problems: Using Collaborative Competency Between Infectious Diseases, Podiatry, and Pathology to Improve the Care of Patients with Diabetic Foot Osteomyelitis

BACKGROUND

Diabetic foot osteomyelitis is a common infection where treatment involves multiple services, including infectious diseases, podiatry, and pathology. Despite its ubiquity in the hospital, consensus on much of its management is lacking.

METHODS

Representatives from infectious diseases, podiatry, and pathology interested in quality improvement developed multidisciplinary institutional recommendations culminating in an educational intervention describing optimal diagnostic and therapeutic approaches to diabetic foot osteomyelitis (DFO). Knowledge acquisition was assessed by preintervention and postintervention surveys. Inpatients with forefoot DFO were retrospectively reviewed before and after intervention to assess frequency of recommended diagnostic and therapeutic maneuvers, including appropriate definition of surgical bone margins, definitive histopathology reports, and unnecessary intravenous antibiotics or prolonged antibiotic courses.

RESULTS

A postintervention survey revealed significant improvements in knowledge of antibiotic treatment duration and the role of oral antibiotics in managing DFO. There were 104 consecutive patients in the preintervention cohort (April 1, 2018, to April 1, 2019) and 32 patients in the postintervention cohort (November 5, 2019, to March 1, 2020), the latter truncated by changes in hospital practice during the coronavirus disease 2019 pandemic. Noncategorizable or equivocal disease reports decreased from before intervention to after intervention (27.0% versus 3.3%, respectively; P = .006). We observed nonsignificant improvement in correct bone margin definition (74.0% versus 87.5%; P = .11), unnecessary peripherally inserted central catheter line placement (18.3% versus 9.4%; P = .23), and unnecessary prolonged antibiotics (21.9% versus 5.0%; P = .10). In addition, by working as an interdisciplinary group, many solvable misunderstandings were identified, and processes were adjusted to improve the quality of care provided to these patients.

CONCLUSIONS

This quality improvement initiative regarding management of DFO led to improved provider knowledge and collaborative competency between these three departments, improvements in definitive pathology reports, and nonsignificant improvement in several other clinical endpoints. Creating collaborative competency may be an effective local strategy to improve knowledge of diabetic foot infection and may generalize to other common multidisciplinary conditions.

Meta-Analysis: Outcomes of Surgical and Medical Management of Diabetic Foot Osteomyelitis

BACKGROUND

The aim of this study was to evaluate clinical outcomes in the published literature on medical and surgical management of diabetic foot osteomyelitis (DFO).

METHODS

A PubMed and Google Scholar search of articles relating to DFO was performed over the dates of January 1931 to January 2020. Articles that involved Charcot arthropathy, case reports, small case series, review articles, commentaries, nonhuman studies, and non-English articles were excluded. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to rate the bias of each study. A meta-analysis was performed using random-effects and inverse variance methods. The search yielded 1192 articles. After review and the removal of articles that did not meet inclusion criteria, 28 articles remained. Eighteen articles were related to the medical management of DFO and 13 articles were related to surgical management. Three articles looked at a combination of medical and surgical management and were included in both groups. Heterogeneity was evaluated using Cochran Q, I 2, τ2, and τ.

RESULTS

The average success rate was 68.2% (range, 17.0%-97.3%) for medical treatment and 85.7% (range, 65.0%-98.8%) for surgical and medical treatment. There were significant inconsistencies in accounting for peripheral arterial disease and peripheral neuropathy. There was significant heterogeneity in outcomes between studies. However, there was a high rate of successful treatment and a wide range between patients with medical treatment and combined surgical and medical treatment.

CONCLUSIONS

Additional properly designed prospective studies with gold-standard references for diagnosing osteomyelitis are needed to help determine whether medical management of DFO can be successful without surgical intervention.

Oral Versus Intravenous Antibiotics for Residual Osteomyelitis After Amputation in the Diabetic Foot

The standard management for residual osteomyelitis following amputation in a diabetic foot infection includes a prolonged course of intravenous antibiotic agents. The purpose of this analysis was to investigate whether oral antibiotic therapy led to treatment failure more than intravenous antibiotic therapy for this indication. The primary endpoint was treatment failure within one year of the initial amputation, defined by re-operation for residual osteomyelitic infection or a remaining nonhealing wound at the surgical site. All patients received at least 4 weeks of antibiotics and were chosen for oral or intravenous route of administration by infectious disease specialists. Characteristics including age, sex, hemoglobin A1c, BMI, tobacco use, PVD, homelessness and IDSA classification were also assessed for influence on antibiotic success and failure. Of the 65 patients meeting inclusion criteria, treatment failure occurred in 32 and treatment success occurred in 33. Of the treatment failures, 17 (53%) were in the intravenous group, and 15 (47%) were in the oral group. The differences between the modalities of antibiotic administration and their failure rates were not found to be statistically significant (p = .28 (proportional difference: -14%, 95% confidence interval [CI]:-36% to 10%)).

The effectiveness of systemic antibiotics for osteomyelitis of the foot in adults with diabetes mellitus: a systematic review protocol

Background

Osteomyelitis of the foot is a major complication of diabetes that can be limb and life threatening. Systemic antibiotic pharmacotherapy is often used first line to eradicate infection and allow restoration of devitalised bone.

The aim is to conduct a systematic review of the effectiveness of systemic antibiotics on osteomyelitis of the foot in adults with diabetes mellitus.

Methods

A systematic review of all interventional studies treating osteomyelitis with systemic antibiotics in participants with diabetes mellitus and an ulcer of the foot below the malleoli will be conducted. Studies not available in English and in people below the age of 18 will be excluded. Study selection will follow the Patient Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA-P guidelines). The quality of the studies will be assessed using the Cochrane risk-of-bias tool (RoB 2) for all randomised controlled trials and the Newcastle–Ottawa Scale (NOS) will be used for non-randomised controlled trials. Electronic databases will be searched with no timeline restrictions.

Data Extraction

All identified references will be imported to the Rayyan Application. Studies for eligibility will be screened by two reviewers. One reviewer will perform the data extraction and quality appraisal will be conducted by two authors. If sufficient data is available, the quality will be analysed and a meta-analysis will be performed. Data synthesis will be conducted, and meta-analysis undertaken using RevMan 5.4.1 Meta-analysis software. Non-parametric data may be compared between selective intervention and outcomes.

Discussion

The results of this systematic review will identify the effectiveness of systemic antibiotic therapy on osteomyelitis of the foot in people with diabetes based on the set outcome measure criteria. The findings will establish if there are existing consistent standards or variation in practice when treating diabetic foot osteomyelitis (DFO). The study may establish if guidelines are required to standardise practice when treating DFO with systemic antibiotic therapy. This systematic review protocol will synthesise the existing evidence on the effectiveness of systemic antibiotic therapy for treating DFO.

Trial registration

International Prospective Register for Systematic Reviews (PROSPERO) number CRD42021245424.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00554-3.

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.

Early oral switch to combined cefixime therapy for management of osteoarticular infections in pediatric sickle cell disease patients: A descriptive analysis

BACKGROUND

The treatment of osteoarticular infections in pediatric patients with sickle cell disease (SCD) is a challenging task for the practitioner. The aim of this study is to evaluate cefixime for the treatment of osteoarticular infections in pediatric SCD patients by retrospective design.

METHODS

This study was done in the pediatric hospital of King Saud Medical City, Riyadh, Saudi Arabia. The data was obtained from medical records of patients aged 1-16 years admitted between January 2019 to December 2020, diagnosed with SCD and received cefixime for the treatment of OI. A descriptive study for pediatric patients admitted between January 2019 to December 2020 diagnosed with sickle cell disease and diagnosed with osteoarticular infection. All patients were treated with cefixime. Medians and interquartile ranges (IQRs) were used for the descriptive analysis.

RESULTS

A total of 260 patients were screened, and 51 cases [osteomyelitis (OM), n = 43, and septic arthritis (SA), n = 8] met the inclusion criteria. The median age of OM patients was 7 years, with males making up 67.4% of the cohort. The median length of IV antibiotics and hospital stays were 10 days and 11 days, respectively. The median total duration of antibiotic use was 37 and 25 days for OM and SA, respectively. The treatment success rate was 88% in OM cases and 100% in SA patients. Readmission was noted in 39.5% of the OM patients, while only 25% of the SA patients were recorded for reinfection.

CONCLUSION

The study's findings revealed that Cefixime is a viable oral alternative for treating osteoarticular infection in pediatric SCD patients. Nonetheless, a prospective investigation is required to corroborate the findings of this study.

Are Surrogate Markers for Diabetic Foot Osteomyelitis Remission Reliable?

BACKGROUND

We aimed to evaluate surrogate markers commonly used in the literature for diabetic foot osteomyelitis remission after initial treatment for diabetic foot infections (DFIs).

METHODS

Thirty-five patients with DFIs were prospectively enrolled and followed for 12 months. Osteomyelitis was determined from bone culture and histologic analysis initially and for recurrence. Fisher exact and χ2 tests were used for dichotomous variables and Student t and Mann-Whitney U tests for continuous variables (α = .05).

RESULTS

Twenty-four patients were diagnosed as having osteomyelitis and 11 as having soft-tissue infections. Four patients (16.7%) with osteomyelitis had reinfection based on bone biopsy. The success of osteomyelitis treatment varied based on the surrogate marker used to define remission: osteomyelitis infection (16.7%), failed wound healing (8.3%), reulceration (20.8%), readmission (16.7%), amputation (12.5%). There was no difference in outcomes among patients who were initially diagnosed as having osteomyelitis versus soft-tissue infections. There were no differences in osteomyelitis reinfection (16.7% versus 45.5%; P = .07), wounds that failed to heal (8.3% versus 9.1%; P = .94), reulceration (20.8% versus 27.3%; P = .67), readmission for DFIs at the same site (16.7% versus 36.4%; P = .20), amputation at the same site after discharge (12.5% versus 36.4%; P = .10). Osteomyelitis at the index site based on bone biopsy indicated that failed therapy was 16.7%. Indirect markers demonstrated a failure rate of 8.3% to 20.8%.

CONCLUSIONS

Most osteomyelitis markers were similar to markers in soft-tissue infection. Commonly reported surrogate markers were not shown to be specific to identify patients who failed osteomyelitis treatment compared with patients with soft-tissue infections. Given this, these surrogate markers are not reliable for use in practice to identify osteomyelitis treatment failure.

A Meta-Analysis of the Outcomes of Resection Arthroplasty for Resistant Hallucal Diabetic Ulcers

The standard medical care (SC) of non-infected diabetic foot ulcers (DFUs) has been reported to yield varying rates of wound healing with high recurrence rate in non-infected wounds. Conservative surgery has been advanced as an alternative to SC in treating resistant non-complicated and complicated DFUs. Studies reporting resection arthroplasty (RA) of the first metatarsal head stated high healing rates with less recurrence. The aim of this meta-analysis is to quantitatively assess the efficacy of the RA procedure. Based on 9 included studies (3 case-control and 6 case-series) with 225 patients (244 feet, 244 hallucal plantar ulcers) and a mean follow-up period was of 22.8 ±13.3 months, the weighted estimates of comparative studies (RA vs. SC) were as follows: healing rate (100% vs. 79.9%, p = .0001), time to heal (3.3 ±0.28 vs. 8.4 ±1.5 weeks, p = .002), recurrence rate (5.7% vs. 25.4%, p = .001) and transfer rate (4.5% vs. 1.4%, p = .1). Similar values were found when analyzing case-series of non-infected and infected wounds treated with RA. Based on the available evidence, resection arthroplasty of the first ray is to be considered an effective conservative surgery in treating resistant or complicated hallucal neuropathic ulcers. Further prospective controlled trials are warranted to validate the review findings.

Long-Term Complications after Surgical or Medical Treatment of Predominantly Forefoot Diabetic Foot Osteomyelitis: 1 Year Follow Up

AIM

To compare long-term complications according to the treatment received for management of diabetic foot osteomyelitis (surgical or medical) at 1 year follow up.

DESIGN AND PARTICIPANTS

A prospective observational study was conducted involving 116 patients with diabetic foot osteomyelitis. The patients received surgical or medical treatment based on the principles described in the literature. To register the development of a complication, both groups of treatments were followed-up 1 year after the ulcer had healed.

RESULTS

Ninety-six (82.8%) patients received surgical treatment and 20 (17.2%) medical treatment. No differences were found in the time to healing between both groups of treatment, 15.7 ± 9.2 weeks in the surgical group versus 16.4 ± 12.1 weeks in the medical group; p = 0.103. During follow up, 85 (73.3%) patients developed complications without differences between both groups, 68 (70.8%) in the surgical group versus 17 (85%) in the medical group (p = 0.193). The most common complication in both groups was re-ulceration. We did not observe significant differences comparing complication-free time survival between both treatments (p = 0.665).

CONCLUSION

The onset of complications after healing in patients who suffered from diabetic foot osteomyelitis was not associated with the treatment received. Surgical and medical approaches to the management of diabetic foot osteomyelitis produced similar results in long-term follow up.

Medical Versus Surgical Treatment for the Management of Diabetic Foot Osteomyelitis: A Systematic Review

A systematic review and quality assessment was performed to assess the management of diabetic foot osteomyelitis by medical or surgical treatment. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist was used. All selected studies were evaluated using the Cochrane Risk of Bias Tool to assess the risk of bias for randomized controlled trials. The literature was revised using PubMed (Medline) and Embase (Elsevier) up to September 2020 to identify clinical trials assessing medical or surgical treatment to manage diabetic foot osteomyelitis. A total of six clinical trials that met our inclusion criteria, with a total of 308 participants. Healing rate, complete closure of the wound, and type of complications were the outcomes evaluated. Risk of bias assessment showed that only two of the six clinical trials included in the systematic review had a low risk of bias. Based on our findings, we believe that the management of diabetic foot osteomyelitis remains challenging. There are few high-quality clinical trials that both stratify clinical presentations and compare these treatments. We conclude that the available evidence is insufficient to identify the best option to cure diabetic foot osteomyelitis.

The Infected Diabetic Foot: Re-evaluating the Infectious Diseases Society of America Diabetic Foot Infection Classification

BACKGROUND

We provide evidence to revise the Infectious Diseases Society of America (IDSA) diabetic foot infection classification by adding a separate tier for osteomyelitis and evaluating if moderate and severe infection criteria improve the classification's ability to direct therapy and determine outcomes.

METHODS

We retrospectively evaluated 294 patients with moderate and severe infections. Osteomyelitis was confirmed by bone culture or histopathology. Soft tissue infection (STI) was based on negative bone culture, magnetic resonance imaging, or single-photon emission computed tomography. We stratified STI and osteomyelitis using IDSA criteria for moderate and severe infections and compared outcomes and complications.

RESULTS

Osteomyelitis patients had greater antibiotic duration (32.5 ± 46.8 vs 63.8 ± 55.1 days; P < .01), surgery frequency (55.5% vs 99.4%; P < .01), number of surgeries (2.1 ± 1.3 vs 3.3 ± 2.3; P < .01), amputations (26.3% vs 83.4%; P < .01), reinfection (38.0% vs 56.7%; P < .01), and length of stay (14.5 ± 14.9 vs 22.6 ± 19.0 days; P < .01). There were no differences in moderate and severe STI outcomes except for infection readmissions (46.2% vs 25.0%; P = .02), and acute kidney injury (31.2% vs 50.0%; P = .03). There were no differences in moderate and severe osteomyelitis except the number of surgeries (2.8 ± 2.1 vs 4.1 ± 2.5; P < .01) and length of stay (18.6 ± 17.5 vs 28.2 ± 17.7; P < .01).

CONCLUSIONS

The IDSA classification better reflects outcomes if risk categories are stratified by STI or osteomyelitis and moderate and severe infections are not categorized separately.

Three versus six weeks of antibiotic therapy for diabetic foot osteomyelitis: A prospective, randomized, non-inferiority pilot trial

BACKGROUND

In patients with diabetic foot osteomyelitis (DFO) who underwent surgical debridement, we investigated whether a short (3 weeks), compared with a long (6 weeks) duration of systemic antibiotic treatment is associated with non-inferior results for clinical remission and adverse events (AE).

METHODS

In this prospective, randomized, non-inferiority, pilot trial, we randomized (allocation 1:1), patients with DFO after surgical debridement to either a 3-week or a 6-week course of antibiotic therapy. The minimal duration of follow-up after end of therapy was two months. We compared outcomes using Cox regression and non-inferiority analyses (25% margin, power 80%).

RESULTS

Among 93 enrolled patients (18% females; median age 65 years), 44 were randomized to the 3-week arm and 49 to the 6-week arm. The median number of surgical debridement was 1 (range, 0-2 interventions). In the intention-to-treat (ITT) population, remission occurred in 37 (84%) of the patients in the 3-week arm compared to 36 (73%) in the 6-week arm (p=0.21). The number of AE was similar in the two study arms (17/44 vs. 16/49; p=0.51), as were the remission incidences in the per-protocol (PP) population (33/39 vs. 32/43; p=0.26). In multivariate analysis, treatment with the shorter antibiotic course was not significantly associated with remission (for the ITT population, hazard ratio 1.1, 95%CI 0.6-1.7; for the PP population hazard ratio 0.8, 95%CI 0.5-1.4).

CONCLUSIONS

In this randomized, controlled pilot trial, a post-debridement systemic antibiotic therapy course for DFO of 3-weeks gave similar (and statistically non-inferior) incidences of remission and AE to a course of 6 weeks.

Role of inflammatory markers in the healing time of diabetic foot osteomyelitis treated by surgery or antibiotics

OBJECTIVE

To analyse the predictive role of inflammatory markers in the healing time of diabetic foot osteomyelitis treated by surgery or antibiotics.

METHODS

An observational study of patients with diabetic foot ulcers (DFU) and clinically suspected osteomyelitis. The patients underwent surgical or antibiotic treatment for bone infection in a specialised diabetic foot unit. Blood samples were taken from each patient to analyse biomarkers. The main outcome was the number of weeks until healing occurred.

RESULTS

A total of 116 patients took part in the study. The number of weeks until healing was similar for both groups (surgical n=96 and antiobiotic n=20, treatments). No association was observed among biomarkers as predictors of time-to-healing.

CONCLUSION

There is not enough evidence to define the prognostic role of inflammatory markers in the healing time of DFUs complicated with diabetic foot osteomyelitis, regardless of the treatment administered.

Principles and practice of antibiotic stewardship in the management of diabetic foot infections

PURPOSE OF REVIEW

Systemic antibiotic therapy in persons with a diabetic foot infection (DFI) is frequent, increasing the risk of promoting resistance to common pathogens. Applying principles of antibiotic stewardship may help avoid this problem.

RECENT FINDINGS

We performed a systematic review of the literature, especially seeking recently published studies, for data on the role and value of antibiotic stewardship (especially reducing the spectrum and duration of antibiotic therapy) in community and hospital populations of persons with a DFI.

SUMMARY

We found very few publications specifically concerning antibiotic stewardship in persons with a DFI. The case-mix of these patients is substantial and infection plays only one part among several chronic problems. As with other types of infections, attempting to prevent infections and avoiding or reducing the spectrum and duration of antibiotic therapy are perhaps the best ways to reduce antibiotic prescribing in the DFI population. The field is complex and necessitates knowledge over the current scientific literature and clinical experience. On a larger scale, clinical pathways, guidelines, and recommendations are additionally supportive.

Correlation between Empirical Antibiotic Therapy and Bone Culture Results in Patients with Osteomyelitis

OBJECTIVE

To analyze the correlation between empirical antibiotic therapies prescribed in primary care centers by general practitioners and the microbiology results of bone culture in patients with diabetic foot-related osteomyelitis.

METHODS

This observational study involved 80 patients with diabetic foot ulcers and clinically suspected osteomyelitis. The patients were taking antibiotics prescribed by general practitioners to treat diabetic foot infections. Bone samples were taken from every patient for microbiology analysis in a specialized diabetic foot unit.

MAIN OUTCOME MEASURE

The sensitivity of the bone cultures to antibiotics was compared with the patient's previous antibiotic therapy, and antibiotic and bacterial resistance were analyzed.

MAIN RESULTS

The bone cultures from only 16 patients (22.3%) showed sensitivity to the antibiotics that the patient had been prescribed. Fifty-six patients (77.8%) displayed bacterial resistance to the antibiotic that they were taking.

CONCLUSIONS

Awareness and implementation of international antibiotic stewardship guidelines are poor in primary care centers. It is important to establish strategies that foster a better understanding of treatment management standards and ensure the proper implementation of guidelines.

Oral amoxicillin-clavulanate for treating diabetic foot infections

AIM

To assess amoxicillin-clavulanate (AMC) for the oral therapy of diabetic foot infections (DFIs), especially for diabetic foot osteomyelitis (DFO).

METHODS

We performed a retrospective cohort analysis among 794 DFI episodes, including 339 DFO cases.

RESULTS

The median duration of antibiotic therapy after surgical debridement (including partial amputation) was 30 days (DFO, 30 days). Oral AMC was prescribed for a median of 20 days (interquartile range, 12-30 days). The median ratio of oral AMC among the entire antibiotic treatment was 0.9 (interquartile range, 0.7-1.0). After a median follow-up of 3.3 years, 178 DFIs (22%) overall recurred (DFO, 75; 22%). Overall, oral AMC led to 74% remission compared with 79% with other regimens (χ² -test; P = 0.15). In multivariate analyses and stratified subgroup analyses, oral AMC resulted in similar clinical outcomes to other antimicrobial regimens, when used orally from the start, after an initial parenteral therapy, or when prescribed for DFO.

CONCLUSIONS

Oral AMC is a reasonable option when treating patients with DFIs and DFOs.

Infected bone resection plus adjuvant antibiotic-impregnated calcium sulfate versus infected bone resection alone in the treatment of diabetic forefoot osteomyelitis

Background

Managing with diabetic foot osteomyelitis (DFO) is challenging. Even after infective bone resection and thorough debridement, DFO is still difficult to cure and has a high recurrence rate. This retrospective study aims to compare the outcomes of two treatment methods, infected bone resection combined with adjuvant antibiotic-impregnated calcium sulfate and infected bone resection alone, for the treatment of diabetic foot osteomyelitis.

Methods

Between 2015 to 2017, 48 limbs (46 patients) with DFO met the criteria were included for assessment. 20 limbs (18 patients) were included in the calcium sulfate group (the CS group) in which vancomycin and/or gentamicin-impregnated calcium sulfate was used as an adjuvant after infected bone resection while 28 limbs (28 patients) as the control group were undergone infected bone resection only. Systemic antibiotics, postoperative wound care and offloading were continued to be applied following surgery in both groups. The time to healing, healing rate, recurrence rate and amputation rate were compared between the two groups.

Results

In total, 90% (18/20) limbs in the CS group as compared to 78.6% (22/28) infected limbs in the control group went to heal (P = 0.513). The Mean time to healing was 13.3 weeks in the CS group and 11.2 weeks in control group (P = 0.132). Osteomyelitis recurrence rate was 0% (0/18) in the CS group and 36.4% (8/22) in the control group (P = 0.014). Postoperative leakage in calcium sulfate group was 30.0% (6/20) with a mean duration of 8.5 weeks. Amputation rate in the control group was 7.1% (2/28) compared to 0% (0/20) in the CS group (P = 0.153).

Conclusions

Antibiotic-impregnated calcium sulfate as an adjuvant prevents the recurrence of DFO but cannot improve the healing rate, reduce the postoperative amputation rate or shorten the time to healing. Prolonged postoperative leakage as the most common complication can be managed with regular dressing.

Level of Evidence

III, Retrospective Comparative Study.

Evaluation of the Surgical and Pharmacological Treatment of Diabetic Foot Infection: A Retrospective Study

BACKGROUND

Diabetic foot infection is a major cause of patient disabilities and lowers limb amputations, with high treatment costs and hospitalisation requirements.

AIM

Aim of this study was to evaluate surgical wound care plus antibiotic effects in the treatment of mild and moderate diabetic foot infections.

METHODS

This retrospective study involved 60 patients with diabetic foot infections with or without osteomyelitis. The patients were categorised as group 1 mild and group 2 moderate. Both groups were treated using local wound debridement and the systemic administration of antibiotics. Group 1 (16) patients were treated with two regimens of oral antibiotics in two regimens, A (amoxicillin/clavulanate + metronidazole) and B (clindamycin + metronidazole), for 10-14 days. Group 2 (42) patients were treated with oral plus intravenous antibiotics in two regimens, A (ampicillin + cloxacillin + metronidazole) and B (lincomycin + metronidazole), for 6 weeks. The patients followed-up with local wound care specialists for 3 months to evaluate the treatment outcomes (cure, improvement, or failure).

RESULTS

Group 1 had an 80% cure rate under regimen A and a 100% cure rate under regimen B. Group 2 regimen A patients had a 61.5% cure rate and 11.53% improved, while regimen B patients had a 68.75% cure rate and 12.5% improved. Failure in both regimens was 23.8% in 20 patients with osteomyelitis, while 35% were cured and 20% improved during the study period.

CONCLUSION

Local surgical wound care for 3 months with antibiotic regimens for 6 weeks resulted in good response and cure rates, with lower costs and fewer instances of hospitalisation. Intravenous lincomycin and oral metronidazole achieved higher cure responses for moderate diabetic foot infections.

Systematic review of randomized controlled trials on antibiotic treatment for osteomyelitis in diabetes

AIM

To evaluate the efficacy of antibiotic therapy in osteomyelitis treatment among people with diabetes.

METHODS

A systematic search of PubMed, EMBASE, AMED, Web of Science, the WHO trial registry, Cochrane library databases, and ClinicalTrials.gov, in addition to hand-searching, was undertaken in July 2018. Two reviewers independently extracted data. The studies' methodological quality was assessed using the modified Jadad scale. Descriptive analysis was performed.

RESULTS

Seven randomized controlled trials, with 393 participants in total, were included. The antibiotic regimens, treatments and follow-up durations varied among the trials. The total scores showed that the overall methodological quality of the seven studies was high, despite two studies showing some flaws in double-blinding and withdrawals/drop-outs. Of four studies comparing different antibiotic regimens, three implied a similar remission effect, while one implied that ertapenem ± vancomycin treatment showed a higher remission rate than tigecycline treatment; this conclusion was not robust because of low power and small sample size. In the other three studies, which included two different doses of ciprofloxacin, an antibiotics group and a conservative surgical group, and two durations of the same antibiotic strategy, no significant differences in remission were reported between the groups. No difference was observed in the analyses of microbiological outcomes, superinfections and relapse, except adverse events.

CONCLUSIONS

There is no definitive evidence supporting the superiority of any particular antibiotic agent, dose, or administration duration in the treatment of osteomyelitis in diabetes. As the included studies had some flaws and limitations, further research is necessary.

The History of Antibiotic Treatment of Osteomyelitis

Antibiotic treatment of osteomyelitis has evolved substantially over the past 80 years. Traditional teachings (eg, that antimicrobials must be given parenterally, selected based upon ratios of achieved bone vs serum drug levels, and continued for 4–6 weeks) are supported by limited data. New studies are challenging this dogma, however. In this review, we seek to contextualize the discussion by providing a narrative, chronologic review of osteomyelitis treatment spanning the pre-antibiotic era through the present day and by describing the quality of evidence supporting each component of traditional osteomyelitis therapy.

Discordant isolates in bone specimens from patients with recurrent foot osteomyelitis

We compared paired operative bone cultures (initial operation and reoperation) for 35 patients who experienced foot osteomyelitis treatment failure at a single hospital. Concordance was poor (kappa = 0.180). Staphylococcus aureus, gram negatives, and anaerobes were the most common discordant bacteria seen at reoperation, while Enterococcus was the most persistent.

Current health and economic burden of chronic diabetic osteomyelitis

INTRODUCTION

Diabetic foot ulcer (DFU) prevalence is as high as 25% and 40-80% of DFUs become infected (DFI). About 20% of infected ulcers will spread to bone causing diabetic foot osteomyelitis (DFO). DFU costs Medicare $9-13 billion/year. The most expensive costs associated with DFU are inpatient costs and hospital admissions. DFO costs are driven mostly by surgical procedures. DFU patients have a 3-year cumulative mortality rate of 28% and rates approaching 50% in amputated patients.

AREAS COVERED

This review will summarize the current health and economic burden of DFO covering management, epidemiology, and copious costs associated with DFO. The review began by searching PubMed and Cochrane databases for various terms including, 'diabetic osteomyelitis costs,' 'diabetic foot infection,' and 'diabetes and antibiotics.' Additionally, references from retrieved publications were reviewed. The global burden of DFU calls for investigating new therapeutic options.

EXPERT OPINION

For DFI, anti-biofilm agents have had success because they directly deliver antimicrobials to the infection site. For DFO, intraosseous (I/O) antibiotic therapy similarly bypasses the issue of vascular disease, will likely have improved therapeutic efficacy, and reduced costs for DFO patients. I/O antibiotic therapy has had clinical success in one case report already, and may significantly improve the lives of those afflicted with DFO.

Optimal management of diabetic foot osteomyelitis: challenges and solutions

Purpose: Diabetic foot osteomyelitis (DFO) is the most frequent infection associated with diabetic foot ulcers, occurs in >20% of moderate infections and 50%-60% of severe infections, and is associated with high rates of amputation. DFO represents a challenge in both diagnosis and therapy, and many consequences of its condition are related to late diagnosis, delayed referral, or ill-indicated treatment. This review aimed to analyze the current evidence on DFO management and to discuss advantages and disadvantages of different treatment options. Methods: A narrative review of the evidence was begun by searching Medline and PubMed databases for studies using the keywords "management", "diabetic foot", "osteomyelitis", and "diabetic foot osteomyelitis" from 2008 to 2018. Results: We found a great variety of studies focusing on both medical and surgical therapies showing a similar rate of effectiveness and outcomes; however, the main factors in choosing one over the other seem to be associated with the presence of soft-tissue infection or ischemia and the clinical presentation of DFO. Conclusion: Further randomized controlled trials with large samples and long-term follow-up are necessary to demonstrate secondary outcomes, such as recurrence, recurrent ulceration, and reinfection associated with both medical and surgical options.

Modern management of diabetic foot osteomyelitis. The when, how and why of conservative approaches

INTRODUCTION

Diabetic foot osteomyelitis (DFO) has long been considered a complex infection that is both difficult to diagnose and treat, and is associated with a high rate of relapse and limb loss. Areas covered: DFO can usually be diagnosed by a combination of clinical evaluation, serum inflammatory markers and plain X-ray. When the results of these procedures are negative or contradictory, advanced imaging tests or bone biopsy may be necessary. Staphylococcus aureus remains the most frequent microorganism isolated from bone specimens, but infection is often polymicrobial. Antibiotic therapy, preferably with oral agents guided by results of bone culture, for a duration of no more than six weeks, appears to be as safe and effective as surgery in cases of uncomplicated forefoot DFO. Surgery (which should be limb-sparing when possible) is always required for DFO accompanied by necrotizing fasciitis, deep abscess, gangrene or in cases not responding (either clinically or radiographically) to apparently appropriate antibiotic treatment. Expert commentary: Research in the past decade has improved diagnosis and treatment of DFO, and most cases can now be managed with a 'conservative' approach, defined as treatment either exclusively with antibiotics or with surgery removing as little bone and soft tissue as necessary.

Application of white blood cell SPECT/CT to predict remission after a 6 or 12 week course of antibiotic treatment for diabetic foot osteomyelitis

AIMS/HYPOTHESIS

Diabetic foot osteomyelitis is a major risk factor for amputation. Medical treatment allows remission in 53-82% of cases. However, the optimal duration of antibiotic therapy remains controversial as a validated marker of osteomyelitis remission is lacking. The aim of this cohort study was to assess prospectively the remission rate of diabetic foot osteomyelitis medically treated using white blood cell (WBC)-single-photon emission computed tomography (SPECT)/computed tomography (CT) as a predictive marker of remission.

METHODS

Individuals with diabetic foot osteomyelitis that was non-surgically treated between April 2014 and December 2015 were included. All participants were treated with antibiotics alone. WBC-SPECT/CT was performed at 6 weeks and antibiotic treatment discontinued if the clinical signs of soft-tissue infection had resolved and there was no abnormal uptake of labelled WBCs. Treatment was otherwise continued for a total of 12 weeks and then discontinued. For these individuals, another WBC-SPECT/CT was performed at 12 weeks. Remission was defined as the absence of recurrence of osteomyelitis at the same location at 1 year.

RESULTS

Forty-five individuals were included; overall remission rate was 84% at 1 year. A 6 week course of antibiotics was used in 23 participants, 22 of whom were in remission at 1 year (96%); a 12 week course was used for 22 participants, 16 of whom were in remission at 1 year (73%). Sensitivity of WBC-SPECT/CT at 12 weeks was 100%, specificity 56%, positive predictive value 46% and negative predictive value 100%.

CONCLUSIONS/INTERPRETATION

The study suggests that WBC-SPECT/CT could predict remission at the end of antibiotic treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02927678.

Diagnostic and therapeutic update on diabetic foot osteomyelitis

Diabetic foot osteomyelitis (DFO) is the most common infection associated to diabetic foot ulcers (DFU). This review is designed to provide an update on the diagnosis and treatment of DFO based on an analysis of MEDLINE through PubMed using as search criterion "Diabetic Foot Osteomyelitis". Authors have included in this review the most relevant manuscripts regarding diagnosis and treatment of DFO. After review and critical analysis of publications, it may be concluded that diagnosis of DFO is not simple because of its heterogeneous presentation. Clinical inflammatory signs, probe-to-bone test, and plain X-rays are postulated as the basic tests for clinical diagnosis when DFO is suspected. Diagnosis should be supported by laboratory tests, of which ESR (>70mm/h) has been shown to be most precise. MRI is the most accurate imaging test, especially for differential diagnosis with Charcot foot. Pathogen isolation by bone culture is essential when the patient is treated with ATB only. Medical or surgical treatment should be based on the clinical characteristics of the patient and the lesion. Surgery should always be an option if medical treatment fails.

Efficacy of magnetic resonance imaging in diagnosing osteomyelitis in diabetic foot ulcers

BACKGROUND

The clinical diagnosis of osteomyelitis is difficult because of neuropathy, vascular disease, and immunodeficiency; also, with no established consensus on the diagnosis of foot osteomyelitis, the reported efficacy of magnetic resonance imaging (MRI) in detecting osteomyelitis and distinguishing it from reactive bone marrow edema is unclear. Herein, we describe a retrospective study on the efficacy of MRI for decision-making accuracy in diagnosing osteomyelitis in diabetic foot ulcers.

METHODS

Twelve diabetic patients with infected foot ulcers underwent preoperative MRI between January 1, 2008, and December 31, 2011. The findings were compared with the histopathologic features of 67 parts of 45 resected bones, the cut ends of which were also histopathologically evaluated.

RESULTS

Osteomyelitis was disclosed by MRI and histopathologically confirmed in 30 parts. In contrast, bone marrow edema diagnosed by MRI in 29 parts was confirmed in 23; the other six parts displayed osteomyelitis. Among 17 resected bones, 13 cut ends displayed bone marrow edema and four were normal. All of the wounds healed uneventfully.

CONCLUSIONS

In the diagnosis of diabetic foot ulcers, osteomyelitis is often reliably distinguished from reactive bone marrow edema, except in special cases.

Happy@feet application for the management of diabetic foot osteomyelitis

OBJECTIVE

We aimed to develop and implement an application that could improve the management of patients presenting with diabetic foot osteomyelitis.

PATIENTS AND METHODS

Physicians from the multidisciplinary diabetic foot infection team and a software engineer first assessed the needs required for the infection management and application. An experimental version was then designed and progressively improved. A final version was implemented in clinical practice in 2013 by the multidisciplinary diabetic foot infection team of our university hospital.

RESULTS

The application, known as Happy@feet, helps gather and allows access to all required data for patient management, dispenses prescriptions (antibiotics, nursing care, blood tests), and helps follow the evolution of the wound. At the end of the consultation, a customizable letter is generated and may be directly sent to the persons concerned. This application also facilitates clinical and economic research. In 2014, Happy@feet was used to follow 83 patients during 271 consultations, 88 of which were day care hospitalizations.

CONCLUSION

The Happy@feet application is useful to manage these complex patients. Once the learning period is over, the time required for data collection is compensated by the rapid dispense of prescriptions and letters. Happy@feet can be used for research projects and will be used in a remote patient management project.

Treatment Failure and Leg Amputation Among Patients With Foot Osteomyelitis

We sought to identify factors associated with treatment failure and leg amputations among those patients who presented with foot osteomyelitis. Characteristics, treatments, and outcomes for all patients treated for probable or definite foot osteomyelitis (per consensus definition) between January 2011 and March 2015 were reviewed. Multivariate Cox regression models were used to identify risk factors for treatment failure (unanticipated resection of additional bone or leg amputation) and of leg amputation alone. A total of 184 episodes of foot osteomyelitis met inclusion criteria. Treatment failure occurred in 53 (28.8%) and leg amputation in 21 (11.4%). Risk factors for treatment failure included severe/unaddressed peripheral artery disease, homelessness, Pseudomonas aeruginosa or Escherichia coli bone isolates, serum albumin <2.8 mg/dL, hallux involvement, insulin therapy, 60 or more pack-years smoking, and <7 days of directed antibiotic therapy for a positive bone margin. Delayed primary wound closure (ie, staged operations) had significantly lower treatment failure risk. Unanticipated resection of bone was not associated with leg amputation. Foot osteomyelitis treatment failure is common. Various factors can help identify those at risk for treatment failure and/or leg amputation, and further studies should focused whether initial management or follow-up should change when these factors are present.

Consensus on surgical aspects of managing osteomyelitis in the diabetic foot

BACKGROUND

The aim of this study was to develop consensus statements that may help share or even establish 'best practices' in the surgical aspects of managing diabetic foot osteomyelitis (DFO) that can be applied in appropriate clinical situations pending the publication of more high-quality data.

METHODS

We asked 14 panelists with expertise in DFO management to participate. Delphi methodology was used to develop consensus statements. First, a questionnaire elicited practices and beliefs concerning various aspects of the surgical management of DFO. Thereafter, we constructed 63 statements for analysis and, using a nine-point Likert scale, asked the panelists to indicate the extent to which they agreed or disagreed with the statements. We defined consensus as a mean score of greater than 7.0.

RESULTS

The panelists reached consensus on 38 items after three rounds. Among these, seven provide guidance on initial diagnosis of DFO and selection of patients for surgical management. Another 15 statements provide guidance on specific aspects of operative management, including the timing of operations and the type of specimens to be obtained. Ten statements provide guidance on postoperative management, including wound closure and offloading, and six statements summarize the panelists' agreement on general principles for surgical management of DFO.

CONCLUSIONS

Consensus statement on the perioperative management of DFO were formed with an expert panel comprised of a variety of surgical specialties. We believe these statements may serve as 'best practice' guidelines until properly performed studies provide more robust evidence to support or refute specific surgical management steps in DFO.

Neuropathic osteoarthropathy with and without superimposed osteomyelitis in patients with a diabetic foot

Soft tissue and bone infection involving the foot is one of the most common long-term complications of diabetes mellitus, implying a serious impairment in quality of life for patients in the advanced stages of the disease. Neuropathic osteoarthropathy often coexists and differentiating between these two entities is commonly challenging, but crucial, as the management may differ substantially. The importance of correct diagnosis cannot be understated and effective management requires a multidisciplinary approach owing to the complicated nature of therapy in such patients. A missed diagnosis has a high likelihood of major morbidity for the patient, including limb amputation, and over-diagnosis results in a great socioeconomic challenge for healthcare systems, the over-utilization of healthcare resources, and the unwise use of antibiotics. Diagnosis is largely based on clinical signs supplemented by various imaging modalities such as radiography, MR imaging, and hybrid imaging techniques such as F-18 fluorodeoxyglucose-positron emission tomography. In the interests of the management of diabetic foot complications, this review article is aimed on the one hand at providing radiologists with important clinical knowledge, and on the other hand to equip clinicians with relevant radiological semiotics.

Toe-Sparing Surgery for Neuropathic Toe Ulcers With Exposed Bone or Joint in an Outpatient Setting

The purpose of this study was to review the results of aggressive surgical debridement of neuropathic toe ulcers with exposed bone or joint. We identified patients with a single toe ulcer with exposed bone or joint that had been operated on in an outpatient setting. The surgery had included aggressive debridement and was performed using a small curette and rongeur, followed by oral antibiotic treatment at home. Success was defined as complete healing with no recurrence 6 months after full wound closure and epitheliazation was achieved. Twenty-five patients with neuropathic toe ulcers (72% male) had a total of 26 primary operations. Their mean age was 60 ± 12 years. In 22 patients, the neuropathy resulted from diabetes mellitus of 17 ± 9 years’ duration. The mean ulcer duration was 6 weeks (range 1-24). The mean number of visits per patient was 6.5 (range 3-20). The ulcers closed in a median of 5 weeks (8 ± 6 weeks, range 3-24 weeks, Q1-Q3 4-10 weeks). At 6 months, 3 (11.5%) patients had needed a toe amputation for infection or necrosis that could not be controlled. None needed a major amputation or hospitalization related to the ulcer. Toe-sparing surgery is feasible and in a select population can have a high success rate (88%), even though it does dictate more dedicated patient care.

The microbiome of diabetic foot osteomyelitis

The purpose of this investigation was to evaluate the diversity of bacteria in diabetic foot osteomyelitis using a 16S rRNA sequencing approach and to compare the results with conventional culture techniques. In this prospective observational study, we obtained 34 bone samples from patients admitted to our hospital with a moderate–severe diabetic foot infection. We analysed the distribution of the 16S rRNA gene sequences in the bone samples, using an Illumina MiSeq Personal Sequencer. We compared the genera that were detected with the cultured pathogens in the bone samples with conventional techniques. In the 23 samples that had positive results with both techniques, Staphylococcus, Corynebacterium, Streptococcus and Propionibacterium spp. were detected in 20, 18, 13 and 11 samples, respectively. Significantly more anaerobes were detected with 16S rRNA sequencing compared to conventional techniques (86.9 % vs. 23.1 %, p = 0.001) and more Gram-positive bacilli were present (78.3 % vs. 3.8 %, p < 0.001). Staphylococcus spp. were identified in all of the sequenced bone samples that were negative with conventional techniques. Mixed genera were present in 83.3 % (5 of 6) of the negative samples. Anaerobic and fastidious organisms may play a more significant role in osteomyelitis than previously reported. Further studies with larger populations are needed in order to fully understand the clinical importance of the microbial diversity of diabetic foot osteomyelitis.

Outcomes and cost minimisation associated with outpatient parenteral antimicrobial therapy (OPAT) for foot infections in people with diabetes

OBJECTIVE

To determine clinical outcomes in patients with diabetic foot infections receiving outpatient parenteral antimicrobial therapy (OPAT), to evaluate cost savings from the use of OPAT and to analyse demographic, clinical and laboratory data that may predict OPAT failure.

RESEARCH DESIGN AND METHODOLOGY

A retrospective cohort analysis was conducted between 1 January 2007 and 7 July 2012 at a tertiary referral hospital in metropolitan Sydney. Patients with diabetic foot infection were identified from the outpatient parenteral antimicrobial therapy database. Demographic, clinical, laboratory and operative report data were obtained from patient charts and electronic medical records. Potential cost savings were calculated on the estimated cost of expenditure versus the expected savings. Linear regression was used to explore outcomes associated with outpatient parenteral antimicrobial therapy failure.

RESULTS

Fifty-nine patients were identified over the 5-year study period. The outpatient parenteral antimicrobial therapy success rate for diabetic foot infections was 88%. Following the resolution of the primary episode of infection, new infective episodes within the study period were high (n = 26, 44%). Regression analysis of variables for OPAT failure failed to indicate any factors reaching statistical significance. A total of 1569 days were saved by using outpatient parenteral antimicrobial therapy for an estimated total cost saving of $983,645 or $16,672 per patient.

CONCLUSION

Outpatient intravenous therapy for diabetic foot infections is an effective mode of treatment that can contribute to significant healthcare savings. High re-infection rates associated with diabetes foot ulceration in this population underline the need for close monitoring and management of these patients in multidisciplinary high-risk foot setting.

Predictors of Outcomes in Diabetic Foot Osteomyelitis Treated Initially With Conservative (Nonsurgical) Medical Management

The optimal way to manage diabetic foot osteomyelitis remains uncertain, with debate in the literature as to whether it should be managed conservatively (ie, nonsurgically) or surgically. We aimed to identify clinical variables that influence outcomes of nonsurgical management in diabetic foot osteomyelitis. We conducted a retrospective study of consecutive patients with diabetes presenting to a tertiary center between 2007 and 2011 with foot osteomyelitis initially treated with nonsurgical management. Remission was defined as wound healing with no clinical or radiological signs of osteomyelitis at the initial or contiguous sites 12 months after clinical and/or radiological resolution. Nine demographic and clinical variables including osteomyelitis site and presence of foot pulses were analyzed. We identified 100 cases, of which 85 fulfilled the criteria for analysis. After a 12-month follow-up period, 54 (63.5%) had achieved remission with nonsurgical management alone with a median (interquartile range) duration of antibiotic treatment of 10.8 (10.1) weeks. Of these, 14 (26%) were admitted for intravenous antibiotics. The absence of pedal pulses in the affected foot (n = 34) was associated with a significantly longer duration of antibiotic therapy to achieve remission, 8.7 (7.1) versus 15.9 (13.3) weeks ( P = .003). Osteomyelitis affecting the metatarsal was more likely to be amputated than other sites of the foot ( P = .016). In line with previous data, we have shown that almost two thirds of patients presenting with osteomyelitis healed without undergoing surgical bone resection.

What's new in the literature: an update of new research since the original WHS diabetic foot ulcer guidelines in 2006

The objective of the paper was to update the diabetic foot ulcer guidelines that were previously published in 2006. We performed a key word search using MEDLINE and Cochrane reviews for publication between January 2006 and January 2012. Articles that fit the inclusion criteria were reviewed and the previous guidelines were updated.

Hybrid imaging with 99mTc-WBC SPECT/CT to monitor the effect of therapy in diabetic foot osteomyelitis

This study sought to assess the utility of monitoring response to treatment of diabetic foot osteomyelitis (DFO) with Tc-99m WBC-labelled single photon emission computed tomography (SPECT/CT) imaging. This is a retrospective cohort study of 20 patients with DFO with sequential Tc-99m WBC-labelled SPECT/CT imaging. Radiologic findings of osteomyelitis were evaluated and imaging results were correlated with clinical outcomes subtracted from chart review. Successful treatment of osteomyelitis was defined by wound healing and/or lack of re-admission for bone infection of the same site within 1 year. The sensitivity, specificity, positive predictive value and negative predictive value of SPECT/CT to determine osteomyelitis treatment remission were 90%, 56%, 69% and 83%, respectively. Tc-99m WBC-labelled SPECT/CT imaging may be useful to help determine treatment outcomes for DFO.

In diabetic foot infections antibiotics are to treat infection, not to heal wounds

INTRODUCTION

Diabetic foot ulcers, especially when they become infected, are a leading cause of morbidity and may lead to severe consequences, such as amputation. Optimal treatment of these diabetic foot problems usually requires a multidisciplinary approach, typically including wound debridement, pressure off-loading, glycemic control, surgical interventions and occasionally other adjunctive measures.

AREAS COVERED

Antibiotic therapy is required for most clinically infected wounds, but not for uninfected ulcers. Unfortunately, clinicians often prescribe antibiotics when they are not indicated, and even when indicated the regimen is frequently broader spectrum than needed and given for longer than necessary. Many agents are available for intravenous, oral or topical therapy, but no single antibiotic or combination is optimal. Overuse of antibiotics has negative effects for the patient, the health care system and society. Unnecessary antibiotic therapy further promotes the problem of antibiotic resistance.

EXPERT OPINION

The rationale for prescribing topical, oral or parenteral antibiotics for patients with a diabetic foot wound is to treat clinically evident infection. Available published evidence suggests that there is no reason to prescribe antibiotic therapy for an uninfected foot wound as either prophylaxis against infection or in the hope that it will hasten healing of the wound.

Six-week versus twelve-week antibiotic therapy for nonsurgically treated diabetic foot osteomyelitis: a multicenter open-label controlled randomized study

OBJECTIVE

Little is known about the optimal duration of antibiotic therapy for diabetic foot osteomyelitis (DFO). This study sought to compare the effectiveness of 6 versus 12 weeks of antibiotic therapy in patients with DFO treated nonsurgically (i.e., antibiotics alone).

RESEARCH DESIGN AND METHODS

This was a prospective randomized trial comparing 6- versus 12-week duration of antibiotic treatment. Remission of osteomyelitis during the monitoring period was defined as complete and persistent (>4 weeks) healing of the wound (if present initially), absence of recurrent infection at the initial site or that of adjacent rays, and no need for surgical bone resection or amputation at the end of a follow-up period of at least 12 months after completion of antibiotic treatment.

RESULTS

Forty patients followed at five French general hospitals were randomized between January 2007 and January 2009, with 20 treated for 6 weeks and 20 treated for 12 weeks with antibiotics. The two groups were comparable for all variables recorded at inclusion in the study. Remission was obtained in 26 (65%) patients, with no significant differences between patients treated for 6 versus 12 weeks (12/20 vs. 14/20, respectively; P = 0.50). We did not identify any significant parameters associated with patient outcome. Fewer patients treated for 6 weeks experienced gastrointestinal adverse events related to antimicrobial therapy compared with patients treated for 12 weeks (respectively, 15 vs. 45%; P = 0.04).

CONCLUSIONS

The present multicenter prospective randomized study provides data suggesting that 6-week duration of antibiotic therapy may be sufficient in patients with DFO for whom nonsurgical treatment is considered.

Management of hospitalized patients with diabetic foot infections

Diabetic foot infections (DFIs), which present with a variety of clinical manifestations, are commonly encountered by clinicians. They are associated with a high morbidity, a high amputation rate, a high mortality, and increased health care costs. An effective management of DFIs requires a multidisciplinary approach with a strong collaboration among all involved health care providers as well as patient involvement. Diagnosing DFIs appropriately requires consideration of the clinical symptoms and signs of infection in addition to supplementary laboratory testing such as inflammatory markers and imaging studies. The comprehensive patient assessment should include the predisposing risk factors for infection; the type, severity, and extent of the infection; and the assessment of neurologic and vascular status, comorbid conditions, and psychosocial factors. The comprehensive management of DFIs include not only effective antibiotic therapy but also surgical debridement, pressure offloading, wound care and moisture, maintaining good vascular perfusion, control of edema and pain, correction of metabolic abnormalities such as hyperglycemia, and addressing psychosocial and nutritional issues. Discharge planning that addresses full medical and social needs along with suitable follow-up, patient education and counseling, and clear communication with outpatient providers are critical for ensuring a safe and successful transition to outpatient management of hospitalized patients with DFIs.

Staphylococcus aureus–Related Diabetic Osteomyelitis

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

Do Diabetic Foot Infections With Methicillin-Resistant Staphylococcus aureus Differ From Those With Other Pathogens?

There is controversy as to whether or not diabetic foot infections (DFIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with worse outcomes than DFIs caused by other pathogens. To address this issue we performed a nonsystematic literature search of published articles in English language journals seeking studies reporting on the outcomes of DFIs related to their microbiology. We retrieved 48 articles published from 1999 to 2013 that described a total of 7771 cases of DFI. The overall proportion of DFIs with an isolate of S aureus was about 30%; just over one third of these (11% of all cases) were MRSA strains. Among the DFI cases caused by MRSA 1543 were episodes of soft tissue infections and 113 of osteomyelitis, while non-MRSA organisms caused 5761 soft tissue infections and 354 cases of osteomyelitis. Only 5 of the included articles attempted a comparison between DFI caused by MRSA and those caused by other pathogens, with no clear differences noted. The median total duration of antibiotic therapy for DFI caused by MRSA was 26 days, of which a median of 10 days was given intravenously. Only a few articles reported the proportion of patients with a recurrence, but they often did not differentiate between MRSA and non-MRSA cases. Four publications reported a worse functional or microbiological outcome in MRSA, compared to non-MRSA, cases, but the findings were variable and differences did not seem to be significant. Many trials failed to adjust for case-mix or to definitively demonstrate a relationship between microbiology and outcomes. Few of the articles specifically commented on whether the MRSA isolates were health care- or community-acquired strains. Notwithstanding the substantial limitations of the available literature, there does not appear to be a need for any special treatment for DFI caused by MRSA. The current guidelines for treating according to established international recommendations seem appropriate.