Comparison of microbiological results obtained from per-wound bone biopsies versus transcutaneous bone biopsies in diabetic foot osteomyelitis: a prospective cohort study

BedBiopsy: Diagnostic performance of bedside ultrasound-guided bone biopsies for the management of diabetic foot infection

OBJECTIVE

We aimed to assess the feasibility and diagnostic performance of ultrasound-guided bone biopsies at the bedside of diabetic patients admitted for suspected foot osteitis not requiring surgery.

RESEARCH DESIGN AND METHODS

In this retrospective monocentric study, we compared the performance of ultrasound-guided (n = 29 consecutive patients, Dec.2020-Oct.2022) versus surgical (n = 24 consecutive patients, Jan.2018-Nov.2020) bone biopsies at confirming or ruling out diabetic foot osteitis (primary outcome).

RESULTS

Patient characteristics were similar in the two intervention groups, including arteritis prevalence (62.3 %), SINBAD score, and wound location (phalanges 36 %, metatarsus 43 %, and calcaneus 21 %). However, the ultrasound-guided group was older (67 ± 11 versus 60 ± 13 years respectively, P = 0.047) and had more type 2 diabetes (97 % versus 75 %, P = 0.038). Diagnostic performance (i.e., capacity to confirm or rule out suspected osteitis) was similar for ultrasound-guided (28/29 cases: 25 confirmations, 3 invalidations) and surgical (24 confirmations/24) biopsies, P = 0.358. No biopsy-related side effect or complication was observed for either intervention, even for patients on antiaggregation and/or anticoagulation therapy. The mean (± standard deviation) time necessary to perform the biopsy was shorter in the ultrasound-guided group (2.6 ± 3.0 versus 7.2 ± 5.8 days, respectively, P < 0.001) and wound evolution at three months was more favorable (83.3 versus 41.2 %, P = 0.005) (94.4 % versus 66.7 %, respectively, patients with new surgical procedure within six months excluded; P = 0.055). Even though not statistically significant, healing rates in terms of wound and osteitis at six months were also better in the ultrasound-guided group (wound: 40.9 % versus 36.8 %; P = 0.790, and osteitis: 81.8 vs 55.6 % P = 0.071).

CONCLUSION

In diabetic patients with suspected foot osteitis not requiring surgery, bedside ultrasound-guided bone biopsies may constitute a promising alternative to surgical biopsies. This intervention provided excellent tolerance and microbiological documentation, short lead-times, and more favorable wound prognosis.

Chronic Nonspinal Osteomyelitis in Adults: Consensus Recommendations on Percutaneous Bone Biopsies from the Society of Academic Bone Radiologists

The diagnosis and management of chronic nonspinal osteomyelitis can be challenging, and guidelines regarding the appropriateness of performing percutaneous image-guided biopsies to acquire bone samples for microbiological analysis remain limited. An expert panel convened by the Society of Academic Bone Radiologists developed and endorsed consensus statements on the various indications for percutaneous image-guided biopsies to standardize care and eliminate inconsistencies across institutions. The issued statements pertain to several commonly encountered clinical presentations of chronic osteomyelitis and were supported by a literature review. For most patients, MRI can help guide management and effectively rule out osteomyelitis when performed soon after presentation. Additionally, in the appropriate clinical setting, open wounds such as sinus tracts and ulcers, as well as joint fluid aspirates, can be used for microbiological culture to determine the causative microorganism. If MRI findings are positive, surgery is not needed, and alternative sites for microbiological culture are not available, then percutaneous image-guided biopsies can be performed. The expert panel recommends that antibiotics be avoided or discontinued for an optimal period of 2 weeks prior to a biopsy whenever possible. Patients with extensive necrotic decubitus ulcers or other surgical emergencies should not undergo percutaneous image-guided biopsies but rather should be admitted for surgical debridement and intraoperative cultures. Multidisciplinary discussion and approach are crucial to ensure optimal diagnosis and care of patients diagnosed with chronic osteomyelitis.

Calcaneal Bone Biopsy Inconsistency between Specimens Obtained From Trephine and Fine Needle Biopsy Techniques

Standardized methods for osteomyelitis (OM) diagnosis of the lower extremity have proven to be difficult. Preoperative probability of foot osteomyelitis necessitates a combination of clinical, laboratory, imaging evidence (i.e., X-ray, CT, MRI), and bone biopsy to guide diagnosis and treatment. In the recent past, the relative weight that clinicians give to these collections of data to advise potential surgical intervention has been challenged, particularly with histologic evaluation of bone biopsy-traditionally considered "gold standard" in OM diagnosis. This study seeks to further expand this dialogue by retrospectively comparing calcaneal bone biopsies performed by direct visualization trephine approach (performed by Surgeons) vs fine needle biopsy with fluoroscopy guidance (performed by Interventional Radiologists). Results obtained from 57 patients with suspected calcaneal osteomyelitis demonstrate that Trephine obtained samples are significantly more likely to produce histopathologic evidence of OM (p-value: .013), microbiologic evidence of OM (p-value: <.001) and have better histopathologic and microbiologic concordance (p-value: <.001) than calcaneal bone biopsies obtained from Fine Needle Biopsy with fluoroscopy guidance.

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.

State-of-the-art update for diagnosing diabetic foot osteomyelitis: a narrative review

Recently, the International Working Group on the Diabetic Foot and the Infectious Diseases Society of America divided diabetic foot disease into diabetic foot infection (DFI) and diabetic foot osteomyelitis (DFO). DFI is usually diagnosed clinically, while numerous methods exist to diagnose DFO. In this narrative review, the authors aim to summarize the updated data on the diagnosis of DFO. An extensive literature search using "diabetic foot [MeSH]" and "osteomyelitis [MeSH]" or "diagnosis" was performed using PubMed and Google Scholar in July 2023. The possibility of DFO is based on inflammatory clinical signs, including the probe-to-bone (PTB) test. Elevated inflammatory biochemical markers, especially erythrocyte sedimentation rate, are beneficial. Distinguishing abnormal findings of plain radiographs is also a first-line approach. Moreover, sophisticated modalities, including magnetic resonance imaging and nuclear medicine imaging, are helpful if doubt remains after a first-line diagnosis. Transcutaneous bone biopsy, which does not pass through the wound, is necessary to avoid contaminating the sample. This review focuses on the current diagnostic techniques for DFOs with an emphasis on the updates. To obtain the correct therapeutic results, selecting a proper option is necessary. Based on these numerous diagnosis modalities and indications, the proper choice of diagnostic tool can have favorable treatment outcomes.

Is fluoroscopy-guided percutaneous bone biopsy of diabetic foot with suspected osteomyelitis worthwhile? A retrospective study

BACKGROUND

Diabetic foot infection, particularly osteomyelitis, is a major risk factor of amputation in persons with diabetes. Bone biopsy with microbial examination is considered the gold standard of diagnosis of osteomyelitis, providing information about the offending pathogens as well as their antibiotics susceptibility. This allows targeting of these pathogens with narrow spectrum antibiotics, potentially reducing emergence of antimicrobial resistance. Percutaneous fluoroscopy guided bone biopsy allows accurate and safe targeting of the affected bone.

METHODS

In a single tertiary medical institution and over 9 year period, we performed 170 percutaneous bone biopsies. We retrosepctively reviewed the medical record of these patients including patients' demographics, imaging and biopsy microbiology and pathollogic results.

RESULTS

Microbiological cultures of 80 samples (47.1%) were positive with 53.8% of the positive culture showed monomicrobial growth and the remaining were polymicrobial. Of the positive bone samples 71.3% grew Gram-positive bacteria. Staphylococcus aureus was the most frequently isolated pathogen from positive bone cultures with almost one third showing methicillin resistence. Enterococcus species were the most frequently isolated pathogens from polymicrobial samples. Enterobacteriaceae species were the most common Gram-negative pathogens and were more common in polymicrobial samples.

CONCLUSIONS

Percutaneous image-guided bone biopsy is a low-risk, minimally invasive procedure that can provide valuable information about microbial pathogens and therefore enable targeting these pathogens with narrow spectrum antibiotics.

The association between bacteria and outcome and the influence of sampling method, in people with a diabetic foot infection

Purpose

Different bacteria lead to divers diabetic foot infections (DFIs), and some bacteria probably lead to higher amputation and mortality risks. We assessed mortality and amputation risk in relation to bacterial profiles in people DFI and investigated the role of sampling method.

Methods

We included people (> 18 years) with DFI in this retrospective study (2011–2020) at a Dutch tertiary care hospital. We retrieved cultures according to best sampling method: (1) bone biopsy; (2) ulcer bed biopsy; and (3) swab. We aggregated data into a composite determinant, consisting of unrepeated bacteria of one episode of infection, clustered into 5 profiles: (1) Streptococcus and Staphylococcus aureus; (2) coagulase-negative Staphylococcus, Cutibacterium, Corynebacterium and Enterococcus; (3) gram-negative; (4) Anaerobic; and (5) less common gram-positive bacteria. We calculated Hazard Ratio’s (HR’s) using time-dependent-Cox regression for the analyses and investigated effect modification by sampling method.

Results

We included 139 people, with 447 person-years follow-up and 459 episodes of infection. Sampling method modified the association between bacterial profiles and amputation for profile 2. HR’s (95% CI’s) for amputation for bacterial profiles 1–5: 0.7 (0.39–1.1); stratified analysis for profile 2: bone biopsy 0.84 (0.26–2.7), ulcer bed biopsy 0.89 (0.34–2.3), swab 5.9*(2.9–11.8); 1.3 (0.78–2.1); 1.6 (0.91–2.6); 1.6 (0.58–4.5). HR’s (95% CI’s) for mortality for bacterial profiles 1–5: 0.89 (0.49–1.6); 0.73 (0.38–1.4); 2.6*(1.4–4.8); 1.1(0.58–2.2); 0.80(0.19–3.3).

Conclusions

In people with DFI, there was no association between bacterial profiles in ulcer bed and bone biopsies and amputation. Only in swab cultures, low-pathogenic bacteria (profile 2), were associated with a higher amputation risk. Infection with gram-negative bacteria was associated with a higher mortality risk. This study underlined the possible negative outcome of DFI treatment based on swabs cultures.

Reliability and Safety of Bedside Blind Bone Biopsy Performed by a Diabetologist for the Diagnosis and Treatment of Diabetic Foot Osteomyelitis

OBJECTIVE

Bone biopsy (BB) performed by a surgeon or an interventional radiologist is recommended for suspicion of osteomyelitis underlying diabetic foot ulcer (DFU). To facilitate its practice, we developed a procedure allowing bedside blind bone biopsy (B4) by a diabetologist.

RESEARCH DESIGN AND METHODS

We conducted a three-step observational study consisting of a feasibility and safety phase (phase 1) to assess the success and side effects of B4, a validity phase (phase 2) to compare DFU outcomes between positive (B4+) and negative (B4-) bone cultures, and a performance phase (phase 3) to compare B4 with the conventional surgical or radiological procedure basic bone biopsy (B3). Primary end points were the presence of bone tissue (phase 1) and complete DFU healing with exclusive medical treatment at 12 months (phases 2 and 3).

RESULTS

In phase 1, 37 consecutive patients with clinical and/or radiological suspicion of DFU osteomyelitis underwent B4. Bone tissue was collected in all patients with few side effects. In phase 2, a B4+ bone culture was found in 40 of 79 (50.6%) participants. Among B4+ patients, complete wound healing after treatment was 57.5%. No statistical difference was observed with patients with B4- bone culture not treated with antibiotics (71.8%, P = 0.18). In phase 3, the proportion of patients with positive BB was lower in B4 (40 of 79, 50.6%) than in B3 (34 of 44, 77.3%, P < 0.01). However, complete healing was similar (64.6% vs. 54.6%, P = 0.28). No difference in rate of culture contamination was observed.

CONCLUSIONS

B4 is a simple, safe, and efficient procedure for the diagnosis of DFU osteomyelitis with a similar proportion of healing to conventional BB.

Novel strategies to diagnose prosthetic or native bone and joint infections

INTRODUCTION

Bone and Joint Infections (BJI) are medically important, costly and occur in native and prosthetic joints. Arthroplasties will increase significantly in absolute numbers over time as well as the incidence of Prosthetic Joint Infections (PJI). Diagnosis of BJI and PJI is sub-optimal. The available diagnostic tests have variable effectiveness, are often below standard in sensitivity and/or specificity, and carry significant contamination risks during the collection of clinical samples. Improvement of diagnostics is urgently needed.

AREAS COVERED

We provide a narrative review on current and future diagnostic microbiology technologies. Pathogen identification, antibiotic resistance detection, and assessment of the epidemiology of infections via bacterial typing are considered useful for improved patient management. We confirm the continuing importance of culture methods and successful introduction of molecular, mass spectrometry-mediated and next-generation genome sequencing technologies. The diagnostic algorithms for BJI must be better defined, especially in the context of diversity of both disease phenotypes and clinical specimens rendered available.

EXPERT OPINION

Whether interventions in BJI or PJI are surgical or chemo-therapeutic (antibiotics and bacteriophages included), prior sensitive and specific pathogen detection remains a therapy-substantiating necessity. Innovative tests for earlier and more sensitive and specific detection of bacterial pathogens in BJI are urgently needed.

Using a BonE BiOPsy (BeBoP) to determine the causative agent in persons with diabetes and foot osteomyelitis: study protocol for a multicentre, randomised controlled trial

BACKGROUND

Diabetic foot osteomyelitis (DFO) poses a major disease burden. It can generally be treated with long-term antibacterial therapy. International guidelines recommend to base antibacterial therapy choices on percutaneous bone biopsy culture, while in practice, therapy is frequently based on (less invasive) ulcer bed cultures. It is currently unknown if treatment outcomes of DFO differ depending on the chosen diagnostic strategy.

METHODS

The BeBoP trial is a multicentre; randomised controlled; physician-, researcher- and subject-blinded; clinical trial comparing two diagnostic strategies in persons with DFO. Culture-directed antibacterial therapy will be based on either percutaneous bone biopsy culture results (intervention group) or ulcer bed biopsy culture results (comparison group). We will enrol 80 subjects with diabetes mellitus (≥ 18 years) and DFO, and we will use block randomisation stratified per centre to randomise them in a 1:1 allocation. The primary outcome is remission of DFO 12 months after enrolment. The secondary outcomes are the time to remission, signs of inflammation or ulceration at the primary location of infection at 6 and 12 months, microbiological and molecular profiles of culture outcomes, surgical interventions including amputation, total antibacterial therapy duration, infection-free survival days, adverse events, quality of life and survival. We will compare the outcomes by intention-to-treat and per-protocol analysis.

DISCUSSION

We aim to compare clinical remission in persons with DFO treated with antibacterial therapy based on either percutaneous bone biopsy culture results or ulcer bed biopsy culture results.

TRIAL REGISTRATION

Netherlands Trial Register NL 7582 . Registered on 05 March 2019.

Advances in pharmacotherapy for diabetic foot osteomyelitis

Introduction: The diagnosis of diabetic foot osteomyelitis (DFO) is usually clinical. Its severity is related to the location and depth of the lesion, and the presence of necrosis or gangrene. The aetiology of diabetic foot osteomyelitis (DFO) is usually polymicrobial, and DFO is often associated with chronic or recurring ulceration.Areas covered: We built on the  International Working Group on the Diabetic Foot (IWGDF) guidelines on the management of diabetic foot infection, providing an outline of the current and new concepts in pharmacotherapy in DFO. We assess future strategies in both medical, surgical and combination management of DFO.Expert opinion: Surgical removal of infected bone is considered as the standard treatment, but a medical approach of certain selected situations has now proven efficacy in selected patients. The combination of new modalities in local antibiotic delivery may provide better long-term solutions and more lasting remission and avoid the disadvantages of prolonged systemic antibiotics.

Culture Concordance in Different Sections of the Metatarsal Head: Interpretations of Microbiological Results

Microbiological cultures of per-wound bone biopsies have shown a lack of correlation and a high rate of false-negative results when compared with bone biopsy cultures in diabetic foot osteomyelitis. The selection of samples from the area of active osteomyelitis, which contains a complete census of the microorganisms responsible for the infection, is essential to properly guide antimicrobial treatment. We aimed to comparatively evaluate the quantitative and qualitative cultures taken from different areas, in metatarsal heads resected for osteomyelitis. For this purpose, we consecutively selected 13 metatarsal heads from 12 outpatients with plantar ulcers admitted to our diabetic foot unit. Metatarsal heads were divided transversally into 3 portions: plantar (A), central (B), and dorsal (C), and the 39 resulting samples were cultured. Qualitative and quantitative microbiological analysis was performed, and the isolated species and bacterial load, total and species specific, were compared between the 3 metatarsal bone segments. The primary outcome of the study was the bacterial diversity detected in the different bone sections. Cultures were positive in 12 of the 13 included metatarsal heads (92%). A total of 34 organisms were isolated from all specimens. Ten of the 12 cultures (83%) were polymicrobial. Ten of the 13 metatarsal heads (77%) had identical microbiological results in each of the 3 bone sections. The largest number of microorganisms was found in the central section. The overall concordance between sections was 91%. The predominant microorganisms were coagulase-negative staphylococci (41%). Statistical differences were not found in the bioburden between sections (range 3.25-3.41 log₁₀ colony-forming unit/g for all sections; P = .511). The results of our study suggest that microorganisms exhibit a high tendency to spread along the metatarsal bone and that the degree of progression along the bone is species dependent. The central portions of metatarsal bones tend to accumulate a higher diversity of species. Thus, we recommend this area of bone for targeted biopsy in patients with suspected osteomyelitis.

Diagnostic Accuracy of Bone Culture Versus Biopsy in Diabetic Foot Osteomyelitis

OBJECTIVE

To compare the diagnostic accuracy of bone culture (microbiology) and biopsy (histology) in patients with acute or chronic diabetic foot osteomyelitis (DFO).

METHODS

This cross-sectional study involved patients for whom providers had a clinical suspicion of DFO. Two bone samples were taken: one for microbiologic testing and another for histologic testing. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio were calculated for bone culture results in relation to the probability of DFO diagnosis.

RESULTS

Fifty-two patients were included; 69% had positive bone culture results, and 90.4% had positive histology results (P = .013), and of those 90.4%, 25.5% had acute and 74.5% had chronic DFO. The sensitivity of the microbiologic bone culture result was 0.70, the specificity was 0.40, the positive predictive value was 0.92, and the negative predictive value was 0.13.

CONCLUSIONS

Histology provides more accurate diagnosis of DFO than microbiology, especially for patients with chronic DFO. These patients could be underdiagnosed because of false-negative results provided by bone culture. Providers should perform both tests to confirm the presence of DFO.

Treating Diabetic Foot Osteomyelitis: A Practical State-of-the-Art Update

Background and Objectives: Diabetic foot osteomyelitis (DFO) can be difficult to treat and securing optimal clinical outcomes requires a multidisciplinary approach involving a wide variety of medical, surgical and other health care professionals, as well as the patient. Results of studies conducted in the past few years have allowed experts to formulate guidelines that can improve clinical outcomes. Material and Methods: We conducted a narrative review of the literature on treat- ment of DFO, with an emphasis on studies published in the last two years, especially regarding antimicrobial therapies and surgical approached to treatment of DFO, supplemented by our own extensive clinical and research experience in this field. Results: Major amputations were once com- mon for DFO but, with improved diagnostic and surgical techniques, "conservative" surgery (foot- sparing, resecting only the infected and necrotic bone) is becoming commonplace, especially for forefoot infections. Traditional antibiotic therapy, which has been administered predominantly in- travenously and frequently for several months, can often be replaced by appropriately selected oral antibiotic regimens following only a brief (or even no) parenteral therapy, and given for no more than 6 weeks. Based on ongoing studies, the recommended duration of treatment may soon be even shorter, especially for cases in which a substantial portion of the infected bone has been resected. Using the results of cultures (preferably of bone specimens) and antimicrobial stewardship princi- ples allows clinicians to select evidence-based antibiotic regimens, often of a limited pathogen spec- trum. Intra-osseous antimicrobial and surgical approaches to treatment are also evolving in light of ongoing research. Conclusions: In this narrative, evidenced-based review, taking consideration of principles of antimicrobial stewardship and good surgical practice, we have highlighted the recent literature and offered practical, state-of-the-art advice on the antibiotic and surgical management of DFO.

Microbiological Concordance in the Management of Diabetic Foot Ulcer Infections with Osteomyelitis, on the Basis of Cultures of Different Specimens at a Diabetic Foot Center in China

OBJECTIVE

This study aimed to assess the microbiological concordance between swab and soft tissue cultures, and corresponding bone specimen cultures from patients with diabetic foot osteomyelitis (DFO). We aimed to analyze the bone specimens' antimicrobial susceptibilities, and to improve clinical management of diabetic foot ulcer infections by using proper antibiotics.

METHODS

The microbial culture results of ulcer swabs, and soft tissue and bone tissue specimens, and the antimicrobial susceptibility tests of bone specimens from patients with DFO were analyzed in a single diabetic foot center.

RESULTS

A total of 60 patients with results from three specimens were included. Staphylococcus aureus was the most common bacterium isolated from the three specimens. The microbiological results for the three specimens were identical in 12 cases, the culture results from swabs and bone tissue specimens were identical in 14 cases, and the results from soft tissue and bone tissue were identical in 46 cases. The concordance of the results of pathogens isolated between soft tissue and bone specimen cultures was higher than that between the swab and bone cultures. Gram-positive bacteria were more sensitive to moxifloxacin, linezolid, and vancomycin, while Gram-negative bacteria were more sensitive to piperacillin/tazobactam, cefoperazone/sulbactam, and carbapenems.

CONCLUSION

Soft tissue culture results have more reliable microbiological concordance to identify DFO bacteria than swab culture results and targeted antibiotic therapy for DFO should be based on antimicrobial susceptibility testing in bone tissue specimen cultures.

Diabetic Foot Infections: Bacterial Isolates From the Centers and Hospitals of Latin American Countries

Diabetic foot infections (DFIs) are one of the most important reasons for lower limb amputations. An adequate approach to the management of DFI implies control of infection using strategies of tissue debridement and empirical antibiotic treatment based on local microbiology. The aim of this study was to determine the bacterial isolates profile and antibiotic susceptibility patterns in samples from DFI from Latin American centers, on the premise that microbiology of this region differs from that of other continents and influences antimicrobial election. Three hundred and eighty-two samples from soft tissue and bone were studied from 17 centers of 4 countries. Three hundred and seven (80.4%; 95% confidence interval = 75.9-84.2) were positive. Gram negatives (GN) were isolated in 43.8% of all samples, not only in severe but also in mild infections, 51% in bone samples, more frequently in presence of ischemia (47% vs 38%; P = .07) and in wounds with longer duration of the lesion (30-20 days; P < .01). Staphylococcus aureus was the most frequent single germ (19.9%). Gram positives were isolated more frequently in patients without ischemia (53% vs 40%; P = .01). Enterococcus faecalis was the most frequent germ in bone samples (16.8%). Ciprofloxacin and trimethoprim-sulfamethoxazole were the oral antimicrobials most effective against GN. Trimethoprim-sulfamethoxazole and rifampicin were the oral antimicrobials most effective against Staphylococcus. Because of GN high antibiotic resistance patterns, patients treated in an ambulatory setting have to be controlled early after starting empiric treatment to assess response to therapy and hospitalize for parenteral antibiotics if oral treatment fails.

Percutaneous Bone Biopsy for Diabetic Foot Osteomyelitis: A Systematic Review and Meta-Analysis

Background

Diabetes is the leading cause of lower extremity nontraumatic amputation globally, and diabetic foot osteomyelitis (DFO) is usually the terminal event before limb loss. Although guidelines recommend percutaneous bone biopsy (PBB) for microbiological diagnosis of DFO in several common scenarios, it is unclear how frequently PBBs yield positive cultures and whether they cause harm or improve outcomes.

Methods

We searched the PubMed, EMBASE, and Cochrane Trials databases for articles in any language published up to December 31, 2019, reporting the frequency of culture-positive PBBs. We calculated the pooled proportion of culture-positive PBBs using a random-effects meta-analysis model and reported on PBB-related adverse events, DFO outcomes, and antibiotic adjustment based on PBB culture results where available.

Results

Among 861 articles, 11 studies met inclusion criteria and included 780 patients with 837 PBBs. Mean age ranged between 56.6 and 71.0 years old. The proportion of males ranged from 62% to 86%. All studies were longitudinal observational cohorts, and 10 were from Europe. The range of culture-positive PBBs was 56%-99%, and the pooled proportion of PBBs with a positive culture was 84% (95% confidence interval, 73%-91%). There was heterogeneity between studies and no consistency in definitions used to define adverse events. Impact of PBB on DFO outcomes or antibiotic management were seldom reported.

Conclusions

This meta-analysis suggests PBBs have a high yield of culture-positive results. However, this is an understudied topic, especially in low- and middle-income countries, and the current literature provides very limited data regarding procedure safety and impact on clinical outcomes or antibiotic management.

Diagnosing diabetic foot osteomyelitis

Bone involvement during an infection of the diabetic foot represents a serious complication associated with a high risk of amputation, prolonged antibiotic treatment and hospitalization. Diabetic foot osteomyelitis (DFOs) require a multidisciplinary approach given the usual complexity of these situations. DFO should be suspected in most cases especially in the most severe forms of soft tissue diabetic foot infections (DFIs) where the prevalence of bone infection may be up to 60%. Suspicion is based on clinical signs in particular a positive probe-to-bone (PTB) test, elevated inflammatory biomarkers especially erythrocyte sedimentation rate and abnormal imaging assessment using plain X-ray as a first-line choice. The combination of PTB test with plain X-ray has proven effective in the diagnosis of DFO. The confirmation (definite) diagnosis of DFO is based on the results of a bone sample examination obtained by either surgical or percutaneous biopsy. Sophisticated imaging examinations such as Magnetic Resonance Imaging (MRI) and nuclear imaging techniques are useful where doubt persists after first-line imaging assessment. These techniques may also help localize the bone infection site and increase the diagnostic performance of percutaneous bone biopsy. The quality of the microbiological documentation of DFO is likely to improve the adequacy of the antimicrobial therapy especially when medical (ie, no surgical resection of the infected bone tissues) is considered. The use of new (molecular) techniques for the identification of the bone pathogens have not yet proven superiority on classic cultural techniques for the management of such patients.

Diagnosis of infection in the foot in diabetes: a systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potentially mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2018, we searched the literature using PuEbMed and EMBASE for published studies on the diagnosis of diabetic foot infection. On the basis of predetermined criteria, we reviewed prospective controlled, as well as noncontrolled, studies in any language, seeking translations for those not in English. We then developed evidence statements on the basis of the included papers.

RESULTS

From the 4242 records screened, we selected 35 papers that met our inclusion criteria. The quality of all but one of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot scheme correlates with the patient's likelihood of ulcer healing, of lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers are supportive, but not diagnostic, of soft tissue or bone infection. In patients with suspected diabetic foot osteomyelitis, both a positive probe-to-bone test and an elevated erythrocyte sedimentation rate are strongly associated with its presence. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis, but advanced imaging methods help in cases when either the diagnosis or the localization of infection is uncertain.

CONCLUSION

The results of this first reported systematic review on the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is a need for more prospective controlled studies of high quality.

Guidelines on the diagnosis and treatment of foot infection in persons with diabetes (IWGDF 2019 update)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the prevention and management of diabetic foot disease since 1999. This guideline is on the diagnosis and treatment of foot infection in persons with diabetes and updates the 2015 IWGDF infection guideline. On the basis of patient, intervention, comparison, outcomes (PICOs) developed by the infection committee, in conjunction with internal and external reviewers and consultants, and on systematic reviews the committee conducted on the diagnosis of infection (new) and treatment of infection (updated from 2015), we offer 27 recommendations. These cover various aspects of diagnosing soft tissue and bone infection, including the classification scheme for diagnosing infection and its severity. Of note, we have updated this scheme for the first time since we developed it 15 years ago. We also review the microbiology of diabetic foot infections, including how to collect samples and to process them to identify causative pathogens. Finally, we discuss the approach to treating diabetic foot infections, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and for bone infections, when and how to approach surgical treatment, and which adjunctive treatments we think are or are not useful for the infectious aspects of diabetic foot problems. For this version of the guideline, we also updated four tables and one figure from the 2016 guideline. We think that following the principles of diagnosing and treating diabetic foot infections outlined in this guideline can help clinicians to provide better care for these patients.

Feasibility of Percutaneous Bone Biopsy as Part of the Management of Diabetic Foot Osteomyelitis in a 100% Neuropathic, Grade 3 IDSA/IWGDF Population on an Outpatient Basis

The present study aimed to evaluate the feasibility of percutaneous bone biopsy in an ambulatory setting as part of the management of diabetic foot osteomyelitis (DFO) on an outpatient basis. DFO may complicate some cases of apparently nonsevere foot infections in patients with diabetes and greatly increase the risk of a lower extremity amputation. It has been suggested that bone culture-based antibiotic therapy is a predictive factor of success in patients with diabetes treated nonsurgically for osteomyelitis of the foot. It is recommended to identify the causative microorganism(s) by the means of either a surgical or percutaneous bone biopsy taken appropriately to select the proper antibiotic therapy. Percutaneous bone biopsy in patients not requiring surgery is, however, not performed in everyday practice as it should be according to the current recommendations. In the present retrospective study, we report a series of 23 consecutive patients with a suspicion of DFO in whom 28 bone samples were collected by percutaneous biopsy at the bedside in an outpatient setting. The percentage of positive cultures was in accordance with that reported in the literature. The mean number of isolates per specimen was 1.04. After a mean 12-month follow-up, the remission was almost of 78%. No adverse event related to the bone biopsy was noted. After a 1-year follow-up, no recurrence was recorded among the patients in remission. The results of the present study suggest that bedside percutaneous bone biopsy performed in the ambulatory setting is a valuable and safe tool in the management of DFO on an outpatient basis.