The infected diabetic foot: Analysis of diabetic and non-diabetic foot infections.

The aim of this study was to compare outcomes of moderate and severe foot infections in people with and without diabetes mellitus (DM). We retrospectively evaluated 382 patients (77% with DM and 23% non-DM). We collected demographic data, co-morbidities and one-year outcomes including healing, surgical interventions, number of surgeries, length of stay, re-infection and re-hospitalisation. DM patients required more surgeries (2.3 ± 2.2 vs. 1.7 ± 1.3, p = 0.01), but did not have a longer hospital length of stay during the index hospitalisation (DM 10.9 days ±9.2 vs. non-DM = 8.8 days ±5.8, p = 0.43). After the index hospitalisation, DM patients had increased rates of re-hospitalisation for any reason (63.3% vs. 35.2%, CI 1.9-5.2, OR 3.2, p < 0.01), re-infection at the index wound infection site (48% vs. 30.7%, CI 1.3-3.5, OR 2.1, p < 0.01), re-hospitalisation for a foot pathology (47.3% vs. 29.5%, CI 1.3-3.6, OR 2.1, p < 0.01), and longer times to ulcer healing (151.8 days ±108.8 vs. 108.8 ± 90.6 days, p = 0.04). Patients with DM admitted to hospital with foot infections have worse clinical outcomes during the index hospitalisation and are more likely to have re-infection and re-admission to hospital in the next year.

Update of biomarkers to diagnose diabetic foot osteomyelitis: A meta-analysis and systematic review.

The aim of this study was to evaluate the diagnostic characteristics of biomarker for diabetic foot osteomyelitis (DFO). We searched PubMed, Scopus, Embase and Medline for studies who report serological markers and DFO before December 2022. Studies must include at least one of the following diagnostic parameters for biomarkers: area under the curve, sensitivities, specificities, positive predictive value, negative predictive value. Two authors evaluated quality using the Quality Assessment of Diagnostic Accuracy Studies tool. We included 19 papers. In this systematic review, there were 2854 subjects with 2134 (74.8%) of those patients being included in the meta-analysis. The most common biomarkers were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and procalcitonin (PCT). A meta-analysis was then performed where data were evaluated with Forrest plots and receiver operating characteristic curves. The pooled sensitivity and specificity were 0.72 and 0.75 for PCT, 0.72 and 0.76 for CRP and 0.70 and 0.77 for ESR. Pooled area under the curves for ESR, CRP and PCT were 0.83, 0.77 and 0.71, respectfully. Average diagnostic odds ratios were 16.1 (range 3.6-55.4), 14.3 (range 2.7-48.7) and 6.7 (range 3.6-10.4) for ESR, CRP and PCT, respectfully. None of the biomarkers we evaluated could be rated as 'outstanding' to diagnose osteomyelitis. Based on the areas under the curve, ESR is an 'excellent' biomarker to detect osteomyelitis, and CRP and PCT are 'acceptable' biomarkers to diagnose osteomyelitis. Diagnostic odds ratios indicate that ESR, CRP and PCT are 'good' or 'very good' tools to identify osteomyelitis.

Complications of Percutaneous Tendo-Achilles Lengthening for Treatment and Prevention of Diabetic Foot Ulcers: A Systematic Review.

Percutaneous Achilles tendon lengthening is an effective surgical procedure to treat and prevent forefoot and midfoot ulcerations in patients with diabetes. Patients with diabetes are prone to plantar ulcerations due to a combination of factors, such as peripheral neuropathy, decreased tendon elasticity, peripheral vascular disease, and hyperglycemia. Complications such as re-ulceration and transfer lesion to the heel, associated with a calcaneal gait secondary to over-lengthening, are possible with percutaneous Achilles tendon lengthening. Although percutaneous Achilles tendon lengthening is well accepted, the overall incidence of complication has not been well described. A systematic review of the reported data was performed to determine the incidence of complication for percutaneous tendo-Achilles lengthening when used for the treatment and prevention of diabetic plantar ulcerations. Nine studies involving 490 percutaneous lengthening procedures met the inclusion criteria. The overall complication rate was 27.8% (8% with transfer heel ulcerations). Given the high rate of complications associated with a percutaneous Achilles tendon lengthening, careful patient selection and consideration of these risks should be considered prior to proceeding with this procedure. Additional prospective comparative analyses with standardization of surgical technique, degrees of lengthening achieved, and post-operative weightbearing and immobilization modalities are needed to decrease incidence of complication and achieve higher healing rates.

Mönckeberg's medial calcific sclerosis in diabetic and non-diabetic foot infections.

The aim of this study was to evaluate the prevalence and extent of lower extremity Mönckeberg's Medial Calcific Sclerosis (MMCS) in patients with and without diabetes in patients admitted to the hospital for foot infections. This study retrospectively reviewed 446 patients admitted to the hospital with a moderate or severe foot infection. We defined diabetes based on ADA criteria and reviewed electronic medical records for demographics, medical history and physical examination data. Anterior-posterior and lateral foot radiographs were examined to identify the presence and extent of vascular calcification. We categorised MMCS based on anatomical location: ankle joint to the navicular-cuneiform joint, Lis Franc joint to metatarsophalangeal joints and distal to the metatarsophalangeal joints. The prevalence of MMCS was 40.6%. The anatomic extent of MMCS was 19.3% in the toes, 34.3% in the metatarsals and 40.6% in the hindfoot/ankle. Calcification was not common solely in the dorsalis pedis artery (DP) (3.8%) or solely in the posterior tibial artery (PT) (7.0%). Usually, both DP and PT arteries were affected by MMCS (29.8%). The prevalence of MMCS was higher in people with diabetes (in hindfoot and ankle [50.1% vs. 9.9%, p ≤ 0.01]; metatarsals [42.6% vs. 5.9%, p ≤ 0.01]; and toes [23.8% vs. 4.0%, p ≤ 0.01]). People with diabetes were 8.9 (CI: 4.5-17.8) times more likely to have MMCS than those without diabetes. This is a group that often has poor perfusion and needs vascular assessment. The high prevalence of MMCS raises questions about the reliability of the conventional segmental arterial Doppler studies to diagnose PAD.

A Prospective Analysis of the SVS WIfI Classification System to Stratify Immediate and 1-Year Patient Outcomes.

The purpose of this study was to prospectively enroll patients that presented to the emergency department with a lower extremity infection, stratify risk and record outcomes. Risk stratification was performed based on the Society of Vascular Surgery Wound, foot Infection, and Ischemia (WIfI) classification system. This study aimed to establish the efficacy and validity of this classification in predicting patient outcomes during immediate hospitalization and throughout a 1 year follow up. A total of 152 patients were enrolled in the study and of these, 116 met the inclusion criteria and had at least 1 year of follow up for analysis. Each patient was assigned a WIfI score based on wound, ischemia, and foot infection severity according to the classification guidelines. Patient demographics as well as all podiatric and vascular procedures were recorded. The major end points of the study were rates of proximal amputation, time to wound healing, surgical procedures, surgical dehiscence, readmission rates, and mortality. A difference in rates of healing (p = .04), surgical dehiscence (p < .01), and 1 year mortality (p = .01) with increasing WIfI stage as well as across the individual component scores was noted. This analysis further supports the application of the WIfI classification system early during patient care to stratify risk and identify the need for early intervention and a multispecialty team approach to potentially improve outcomes in the severe multicomorbid patient.

Functional Characterization of Neutrophils Allows Source Control Evaluation in a Murine Sepsis Model.

INTRODUCTION: Current surgical guidelines for the treatment of intra-abdominal sepsis recommend interventional source control as the key element of therapy, alongside resuscitation and antibiotic administration. Past trials attempted to predict the success of interventional source control to assess whether further interventional therapy is needed. However, no predictive score could be developed. MATERIALS AND METHODS: We utilized an established murine abdominal sepsis model, the cecal ligation and puncture (CLP), and performed a successful surgical source control intervention after full development of sepsis, the CLP-excision (CLP/E). We then sought to evaluate the success of the source control by characterizing circulating neutrophil phenotype and functionality 24 h postintervention. RESULTS: We showed a significant relative increase of neutrophils and a significant absolute and relative increase of activated neutrophils in septic mice. Source control with CLP/E restored these numbers back to baseline. Moreover, main neutrophil functions, the acidification of cell compartments, such as lysosomes, and the production of Tumor Necrosis Factor-alpha (TNF-α), were impaired in septic mice but restored after CLP/E intervention. CONCLUSIONS: Neutrophil characterization by phenotyping and evaluating their functionality indicates successful source control in septic mice and can serve as a prognostic tool. These findings provide a rationale for the phenotypic and functional characterization of neutrophils in human patients with infection. Further studies will be needed to determine whether a predictive score for the assessment of successful surgical source control can be established.

Digital Biomarkers of Gait and Balance in Diabetic Foot, Measurable by Wearable Inertial Measurement Units: A Mini Review.

People with diabetic foot frequently exhibit gait and balance dysfunction. Recent advances in wearable inertial measurement units (IMUs) enable to assess some of the gait and balance dysfunction associated with diabetic foot (i.e., digital biomarkers of gait and balance). However, there is no review to inform digital biomarkers of gait and balance dysfunction related to diabetic foot, measurable by wearable IMUs (e.g., what gait and balance parameters can wearable IMUs collect? Are the measurements repeatable?). Accordingly, we conducted a web-based, mini review using PubMed. Our search was limited to human subjects and English-written papers published in peer-reviewed journals. We identified 20 papers in this mini review. We found preliminary evidence of digital biomarkers of gait and balance dysfunction in people with diabetic foot, such as slow gait speed, large gait variability, unstable gait initiation, and large body sway. However, due to heterogeneities in included papers in terms of study design, movement tasks, and small sample size, more studies are recommended to confirm this preliminary evidence. Additionally, based on our mini review, we recommend establishing appropriate strategies to successfully incorporate wearable-based assessment into clinical practice for diabetic foot care.

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.

Randomized clinical study to compare negative pressure wound therapy with simultaneous saline irrigation and traditional negative pressure wound therapy for complex foot infections.

The aim of this study was to compare the efficacy of different negative pressure wound therapy (NPWT) devices and NPWT with and without simultaneous irrigation in patients admitted to hospital with moderate and severe foot infections. Ninety patients were randomized in a 12-week prospective, randomized noninferiority trial to compare wound healing in patients with moderate and severe infected foot wounds treated with NPWT after surgery. Inclusion criteria included ABI > 0.5 or toe pressures >30 PVR/mmHg, >18 years of age and exclusion included active Charcot arthropathy, collagen vascular disease, HIV, and hypercoagulable state. We compared two different traditional devices, NPWT-K (KCI, VAC Ulta) and NPWT-C (Cardinal, PRO), and NPWT-I with saline irrigation (Cardinal, PRO). All patients had therapy delivered at 125 mmHg continuous pressure. In patients who received simultaneous saline irrigation (NPWT-I), the administration rate was 15 ml per hour. The primary outcome was the proportion of healed wounds in 12 weeks. Secondary outcomes included surgical wound closure, number of surgeries, length of stay, and time to wound healing. Continuous data was presented as mean ± standard deviation. Analysis of variance was used to compare continuous variables and chi-square to compare dichotomous variables with an alpha of 0.05. There were no differences in outcomes among NPWT-I, NPWT-C, and NPWT-K groups in proportion of healed wounds (63.3%, 50.0%, 46.7% p = 0.39), surgical wound closure (83.3%, 80.0%, 63.3%, p = 0.15), number of surgeries (2.0 ± 0.49, 2.4 ± 0.77, 2.4 ± 0.68, p = 0.06), length of stay (16.3 ± 15.7, 14.7 ± 7.4, 15.3 ± 10.5 days, p = 0.87), time to wound healing (46.2 ± 22.8, 40.9 ± 18.8, 45.9 ± 28.3 days, p = 0.78). We did not identify any significant differences in clinical outcomes or adverse events between patients treated with different NPWT devices or NPWT with and without irrigation.

Clinical Outcomes of Foot Infections in Patients Without Diabetes.

The aim of this study was to report clinical outcomes of moderate and severe foot infections in patients without diabetes. Medical records of 88 nondiabetic patients with foot infections treated at a safety net hospital were retrospectively reviewed. Patients were grouped by the presence of soft-tissue infection (STI) or osteomyelitis (OM). The diagnosis of OM was determined by positive bone culture or histopathology. STIs were defined by negative bone biopsy or negative imaging with magnetic resonance imaging or computed tomography/dual-modality radiolabeled white blood cell single-photon emission computed tomography. Patient outcomes were recorded ≤1 year after admission. Eighty-eight nondiabetic patients admitted to our institution for moderate or severe foot infections were included, 45 OM and 43 STI. No differences were noted in patient characteristics except that OM patients had a higher prevalence of neuropathy (66.7% versus 39.5%, p = .02). OM patients required surgery more often (97.8% versus 67.4%, p < .01), a greater number of surgeries (2.0 ± 1.2 versus 1.4 ± 1.3, p = .02), and more amputations (75.6% versus 11.6%, p < .01) than STI patients. OM patients had a higher proportion of wounds that healed (82.2% versus 62.8%, p = .04). There were no significant differences in reinfection (35.6% versus 25.6%, p = .36), foot-related readmission to hospital (35.6% versus 23.3%, p = .25), or total duration of antibiotics (13.9 ± 10.2 versus 13.5 ± 12.9, p = .87) between OM and STI patients. In conclusion, OM patients required more surgeries and amputations than patients with STIs; however, they had similar rates of reinfection and readmission within a year after the index hospitalization.

The effect of continuous diffusion of oxygen treatment on cytokines, perfusion, bacterial load, and healing in patients with diabetic foot ulcers.

To evaluate continuous diffusion of oxygen therapy (CDO) on cytokines, perfusion, and bacterial load in diabetic foot ulcers we evaluated 23 patients for 3 weeks. Tissues biopsies were obtained at each visit to evaluate cytokines and quantitative bacterial cultures. Perfusion was measured with hyperspectral imaging and transcutaneous oxygen. We used paired T tests to compare continuous variables and independent T tests to compare healers and nonhealers. There was an increase from baseline to week 1 in TGF-ß (P = .008), TNF-α (P = .014), VEGF (P = .008), PDGF (P = .087), and IGF-1 (P = .058); baseline to week 2 in TGF-ß (P = .010), VEGF (P = .051), and IL-6 (P = .031); and baseline to week 3 with TGF-ß (P = .055) and IL-6 (P = .054). There was a significant increase in transcutaneous oxygen after 1 week of treatment on both medial and lateral foot (P = .086 and .025). Fifty-three percent of the patients had at least a 50% wound area reduction (healers). At baseline, there were no differences in cytokines between healers and nonhealers. However, there was an increase in CXCL8 after 1 week of treatment (P = .080) and IL-6 after 3 weeks of treatment in nonhealers (P = .099). There were no differences in quantitative cultures in healers and nonhealers.

Do SIRS Criteria Predict Clinical Outcomes in Diabetic Skin and Soft Tissue Infections?

The aim of this study was to assess whether systemic inflammatory response syndrome (SIRS) is correlated with outcomes in diabetic foot infections (DFIs). We retrospectively reviewed 137 diabetic patients admitted to the hospital with Infectious Diseases Society of America moderate and severe DFIs. We used SIRS criteria to define severe infection based on the presence of at least 2 of the following: heart rate >90 bpm, temperature >38°C or <36°C, respiratory rate >20 breaths per minute, and white blood cell count >12,000/mm3 or <4,000/mm3. Patients with severe DFI were significantly younger (median 49.6 versus 53.6 years, p = .04), less often had type 2 diabetes (88.6% versus 98.9%, p = .01), and less often had a history of previous amputation (15.9% versus 40.9%, p < .01). There were no differences in patients with severe infections defined by SIRS versus moderate infections in the need for surgery (47.7% versus 59.1%, p = .27), any amputation (20.5% versus 29.0%, p = .29), leg amputations (6.8% versus 7.5%, p = .88), duration of antibiotics (median ± standard deviation 34.1 ± 46.5 versus 31.9 ± 47.2 days, p = .47), or healing within 1 year (68.2% versus 66.7%, p = 1.00). Length of hospital stay was the only outcome variable that was significantly different in severe infections (median 12.7 ± 11.9 versus 7.8 ± 5.8 days, p = .02). Foot-related readmission was more common in moderate infections (46.2% versus 25.0%, p = .02). In conclusion, SIRS criteria for severe infections in diabetic patients with skin and soft tissue infections were not associated with a difference in outcomes other than longer hospital stay.

Outcomes of Foot Infections Secondary to Puncture Injuries in Patients With and Without Diabetes.

It is difficult to compare foot infections in patients with diabetes to those without diabetes because foot infections are uncommon in people without diabetes. The aim of this study is to compare clinical outcomes in people with and without diabetes admitted to the hospital for an infected puncture wound. We evaluated 114 consecutive patients from June 2011 to March 2019 with foot infection resulting from a puncture injury; 83 had diabetes and 31 did not have diabetes. We evaluated peripheral arterial disease (PAD), sensory neuropathy, the need for surgery and amputation, length of hospitalization, and presence of osteomyelitis. Patients with diabetes were 31 times more likely to have neuropathy (91.6% versus 25.8%, p < .001, confidence interval [CI] 10.2 to 95.3), 8 times more likely to have PAD (34.9% versus 6.5%, p = .002, CI 1.7 to 35), and 7 times more likely to have kidney disease (19.3% versus 3.2%, p < .05, CI 0.9 to 56.5). They also took longer before presenting to the hospital (mean 20.1 ± 36.3 versus 18.8 ± 34.8 days, p = .09, CI 13 to 26.5); however, this result was not statistically significant. Patients with diabetes were 9 times more likely to have osteomyelitis (37.3% versus 6.5%, p = .001, CI 1.9 to 38.8). In addition, they were more likely to require surgery (95% versus 77%, p < .001, CI 1.6 to 21.4), required more surgeries (2.7 ± 1.3 versus 1.3 ± 0.8, p < .00001, CI 2.1 to 2.5), were 14 times more likely to have amputations (48.2% versus 6.5%, p < .0001, CI 3.0 to 60.2), and had 2 times longer hospital stays (16.2 ± 10.6 versus 7.5 ± 9 days, p = .0001, CI 11.9 to 15.9. Infected puncture wounds in patients with diabetes often fair much worse with more detrimental outcomes than those in patients without diabetes.

Erbium: Yttrium Aluminum Garnet Laser Accelerates Healing in Indolent Diabetic Foot Ulcers.

The objective of the study was to evaluate the effect of the erbium:yttrium aluminum garnet (YAG) laser on diabetic foot ulcers (DFUs) that had not responded to standard care. We retrospectively evaluated 22 nonhealing DFUs that received at least 4 weeks of standard wound care, demonstrated poor healing response, and subsequently were treated with an erbium:YAG laser. We measured the percent wound area reduction (PWAR) for the 4 weeks before initiating laser therapy and the PWAR for 4 weeks after the initiation of laser therapy. Erbium:YAG laser treatment consisted of 2 components: debridement and resurfacing. The laser settings were the same for all treatments. We used the paired t test to compare pretreatment with posttreatment wound area reduction. During the 4-week period before the initiation of laser therapy, the average PWAR was -33.6%. Four weeks after initiating treatment with the erbium:YAG laser, the average PWAR was 63.4% (p = .002) and 72.7% of wounds had ≥50% PWAR. By 12 weeks, 50% of wounds had healed. Erbium:YAG laser therapy accelerated DFU healing in a cohort of patients with ulcers that had been unresponsive to standard of care therapy.

Ultraviolet-A Light and Negative-Pressure Wound Therapy to Accelerate Wound Healing and Reduce Bacterial Proliferation.

BACKGROUND: Ultraviolet (UV)-A therapy is a simple, inexpensive, and effective modality for wound healing, with tremendous potential to improve healing and reduce clinical infections in a number of clinical settings. To date, application of UV-A relies on bulky and hard-to-dose lamps that provide inconsistent therapy, thus making it difficult to apply therapy that is appropriate for the patient. METHODS: This study was designed to test the effectiveness of a novel wound therapy device that combines UV-A with traditional negative-pressure wound therapy (NPWT) to promote wound healing. Furthermore, we tested the ability of fiberoptic UV-A delivery to inhibit bacterial proliferation. Finally, we assayed the level of DNA damage that results from UV-A as compared to established UV-C therapies. Wound healing studies were performed in a porcine model using an articulated therapy arm that allows for continued therapy administration over an extended time course. Negative-pressure wound therapy was administered alone or with UV-A fiberoptic therapy for 2 weeks. Dressings were changed twice a week, at which time wound area was assessed. RESULTS: Data demonstrate that UV-A with NPWT treatment of wounds results in greater healing than NPWT alone. Using the same therapy device, we demonstrate that exposure of Staphylococcus aureus and Pseudomonas aeruginosa to fiberoptic UV-A results in decreased colony area and number of both bacterial strains. Finally, we show that UV-A induces minimal DNA damage in human fibroblasts and no more DNA damage in wound tissue as compare to intact skin. CONCLUSIONS: These data demonstrate that UV-A can decrease bacterial proliferation and promote wound healing when coupled with NPWT.

Mönckeberg's Medial Calcific Sclerosis Makes Traditional Arterial Doppler's Unreliable in High-Risk Patients with Diabetes.

OBJECTIVE: To assess Mönckeberg's medial calcific sclerosis (MMCS) severity in patients with a diabetic foot infection. METHODS: This was an analysis of 2 randomized clinical trials in which we evaluated the treatment of 233 patients admitted to the hospital for moderate and severe foot infections. Arterial calcification was defined as visible radiopaque arteries on foot and ankle radiographs, recorded as the most distal visible artery involved (toes, metatarsals, and ankle/hindfoot). RESULTS: Most subjects (57.1%, n = 133) had MMCS, with extension to toes in 79 (59.4%), to metatarsals in 32 (24.1%), and to ankle/hindfoot in 22 patients (16.5%). In 7 patients (5.2%) MMCS was solely seen in dorsalis pedis (DP) artery, in 13 patients (9.8%) in posterior tibialis (PT) artery, and in 113 patients (85.0%) MMCS was seen in both arteries. Only 29.2% (n = 68) of DP arteries and 34.8% (n = 81) of PT arteries were not compressible by Doppler. DP and PT arteries were not compressible more often in MMCS (DP 34.3% vs 20.4%, P = .02 and PT 43.1% vs 21.4%, P < .01), toe-brachial indices of ≥0.7 were significantly more common in people without MMCS (46.0% vs 67.4%, P < .01). In contrast, there were no differences in skin perfusion pressure measurements (>50 mmHg; 67.7% vs 68.0%, P = .96), waveforms (biphasic/triphasic 83.5% vs 77.0%, P = .22), and pulse volume recording (9.6 ± 3.3 vs 13.7 ± 36.0) between patients with and without MMCS. CONCLUSION: MMCS is common in patients with diabetic foot infections. MMCS is associated with noncompressible arterial Doppler studies and likely interferes with the accuracy of arterial Doppler studies.

Does antibiotic treatment before bone biopsy affect the identification of bacterial pathogens from bone culture?

There is a common belief and practice that any exposure to oral or parenteral antibiotics prior to bone biopsy makes culture results unreliable. The aim of this article was to evaluate the effect of antibiotic exposure on bacterial yield in DFO microbiology specimens. The authors retrospectively evaluated 114 patients with DFO confirmed by histology. The primary outcome measurement was the proportion of bone biopsies with positive bacterial cultures. There was no statistically significant difference in culture yield in patients who received antibiotics (77.9%) and patients who did not (85.7%, P = .58). This study demonstrates that there were no differences in bacterial yield whether antibiotics were withheld or administered before bone cultures were obtained. The duration of antibiotic use prior to bone biopsy did not change the bacterial yield.

Limited Clinical Utility of Routine Mycobacterial Cultures for the Management of Diabetic Foot Infections.

Mycobacterial infections of the foot and ankle are uncommon. In a cohort of 2340 patients with diabetic foot infection (DFI) in a region with increased prevalence of mycobacterial disease, we identified no clinically significant positive cultures over a 3-year period. Routine mycobacterial culture of DFIs is of limited clinical utility.

Effect of Sensory Neuropathy on the Predictive Value of Inflammatory Biomarkers for Osteomyelitis in Diabetic and Nondiabetic Patients with Foot Infections.

OBJECTIVE: To investigate the predictive value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in persons with and without diabetes with osteomyelitis (OM). METHODS: We evaluated 455 patients in a retrospective cohort study of patients admitted to the hospital with diabetic foot OM (n = 177), diabetic foot soft-tissue infections (STIs) (n = 176), nondiabetic OM (n = 51), and nondiabetic STIs (n = 51). Infection diagnosis was determined through bone culture, histopathologic examination for OM, and/or imaging (magnetic resonance imaging/single-photon emission computed tomography) for STI. The optimal cutoff values of ESR and CRP in predicting OM were determined by receiver operating characteristic curve analysis. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined through contingency tables. RESULTS: In persons without diabetes with STI or OM, the mean ESR and CRP differences were 10.0 mm/h and 2.6 mg/dL, respectively. In contrast, persons with diabetes had higher levels of each: 24.8 mm/h and 6.8 mg/dL, respectively. As a result, ESR and CRP predicted OM better in patients with diabetes. However, when patients were stratified by neuropathy status, ESR remained predictive of OM in diabetic patients with neuropathy (75% sensitivity, 58% specificity) but not in diabetic patients without neuropathy (50% sensitivity, 44% specificity). Also, CRP remained predictive irrespective of neuropathy status. A similar trend was observed in patients without diabetes. CONCLUSIONS: Previous studies have reported that ESR and CRP are predictive of OM. However, this study suggests that neuropathy influences the predictive value of inflammatory biomarkers. The underlying mechanisms require further study.