Retrospective analysis of diabetic foot osteomyelitis management and outcome at a tertiary care hospital in the UK

Significant Publications on Infectious Diseases Pharmacotherapy in 2021

Purpose: To summarize the most noteworthy infectious diseases (ID) pharmacotherapy articles published in peer-reviewed literature in 2021. Summary: Members of the Houston Infectious Diseases Network (HIDN) nominated articles that were deemed to have significant contributions to ID pharmacotherapy in 2021. These nominations included articles pertaining to both general ID, including coronavirus disease 2019 (COVID-19), and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pharmacotherapy. A total of 35 articles were nominated by HIDN: 30 articles pertaining to general ID pharmacotherapy and 5 articles with HIV/AIDS focus. To select the most influential articles of 2021, a survey was created and distributed to members of the Society of Infectious Diseases Pharmacists (SIDP). Of the 239 SIDP members who responded to the survey, there were 192 recorded votes for the top 10 general ID pharmacotherapy articles and 47 recorded votes for the top HIV/AIDS article, respectively. The top publications are summarized. Conclusion: Antimicrobial stewardship and the optimal management of infectious disease states continues to be a priority in the midst of the ongoing coronavirus disease 2019 (COVID-19) global pandemic. In light of the sheer volume of ID-related articles published in the past year, this review aims to aid clinicians in remaining up-to-date on key practice-changing ID pharmacotherapy publications from 2021.

Successful Outpatient Treatment of Severe Diabetic-Foot Myositis and Osteomyelitis Caused by Extensively Drug-Resistant Enterococcus faecalis with Teicoplanin plus Rifampicin: A Case Report

BACKGROUND Foot ulcers are high-morbidity and debilitating complications of diabetes mellitus, and carry significantly increased rates of associated major amputations. They contribute to significantly worse quality of life. Osteomyelitis is a frequent complication of diabetic foot ulcers, since bacteria can contiguously spread from soft tissues to the bone, involving the cortex first and then the bone marrow. Unfortunately, clinically unsuspected osteomyelitis is frequent in persisting diabetic foot ulcers. It is associated with limb amputations and increased mortality. CASE REPORT We describe a 76-year-old man with long-standing insulin-treated type 2 diabetes, who experienced extensively drug-resistant Enterococcus faecalis diabetic foot myositis and osteomyelitis associated with sepsis. He was successfully treated with surgical debridement combined with the administration of teicoplanin plus rifampicin in the outpatient setting, completing, in total, a twelve-week course of antibiotic therapy. CONCLUSIONS Clinically unsuspected osteomyelitis in patients with persisting diabetic foot ulcers has been associated with infections from highly resistant bacteria. Early and accurate diagnosis of diabetic foot osteomyelitis, as well as proper therapeutic approach (antimicrobial and surgical), is of great importance to reduce the risk of minor and major amputations, septic shock leading to multiple organ failure, and overall mortality.

Surgical Diabetic Foot Infections: Is Osteomyelitis Associated With a Worse Prognosis?

It has been reported that patients with diabetes and foot ulcers complicated with osteomyelitis (OM) have a worse prognosis than those complicated with soft tissue infections (STI). Our study aimed to determine whether OM is associated with a worse prognosis in cases of moderate and severe diabetic foot infections requiring surgery. A retrospective series consisted of 150 patients who underwent surgery for diabetic foot infections. We studied the differences between OM versus STI. Furthermore, diabetic foot infections were reclassified into four groups: moderate STI (M-STI), moderate OM (M-OM), severe STI (S-STI), and severe OM (S-OM). The variables associated with prognosis were limb loss, length of hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing (both the initial ulcer and the postoperative wound). No differences in limb salvage, hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing were found when comparing OM with STI. Patients with M-O had a higher rate of recurrences after initial treatment and a longer time to healing when comparing with M-STI. We didn't find any differences between severe infections with or without OM. In conclusion, we have found in our surgical series of diabetic foot infections that OM is not associated with worse prognosis when comparing with STI regarding limb loss rate, length of hospital stays, duration of antibiotic treatment, recurrence of the infection, and time to healing. The results of the present series should further be confirmed by other authors.

Bacterial Diversity, Antibiotic Resistance, and the Risk of Lower Limb Amputation in Younger and Older Individuals With Diabetic Foot Infection

INTRODUCTION

A diabetic foot infection (DFI) contributes to high mortality and morbidity in diabetics due to its often rapid progressive and intricately treatable infection. DFIs are usually a polymicrobial infection and characterizing the entire bacterial load is still challenging. Prompt and effective treatment of DFI is nevertheless mandatory to safe limbs and lives. It is therefore crucial to know the local pathogen spectrum and its antibiotic susceptibility.

METHODS AND MATERIAL

For a 12-month period, we investigated 353 individuals with infected diabetic foot ulcer, their bacterial diversity, and antimicrobial susceptibility at fist-time visit in a Diabetic Foot Care Center in southern Germany.

RESULTS

Cultures yielded 888 species, most of them gram-positive cocci (primary Staphylococcus aureus). The gram-negative sector was mainly formed by Pseudomonas aeruginosa and Enterobacteriacae. Because the prevalence of multiresistant species was surprisingly low (0.9% of isolated strains), we suggest penicillins with β-lactamase inhibitor in case of gram-positive-dominated infection or piperacillin/tazobactam or rather carbapenems with equal efficacy when gram-negative species are involved.

Retrospective study of outcomes of short versus long duration of antibiotic therapy for residual osteomyelitis in surgically resected diabetic foot infection

INTRODUCTION

Optimal treatment duration for residual osteomyelitis (OM) post-amputation in diabetic foot infection (DFI) remains unclear, with resultant heterogeneity in prescribing noted in clinical practice. We aimed to identify a difference in outcomes of long duration of antibiotics (LD) with short duration (SD) in patients with culture-positive proximal bone specimen post-amputation.

METHODS

In this single-centre retrospective cohort study (Melbourne, Australia), we analysed antibiotic duration of DFI patients requiring amputation with culture-positive proximal bone specimen over a 31 month period (January 2019-September 2021). Primary outcome was reamputation or debridement at the same and/or contiguous site of amputation at 6 months. Secondary outcomes were readmission to hospital and/or recommencement of antibiotics for DFI at the same and/or contiguous site at 6 months.

RESULTS

Among 92 patients (83% male, median age 67 years), 26 received <4 weeks (SD) and 66 received ≥4 weeks (LD) antibiotic therapy. In the SD group, primary outcome occurred in 9 patients (35%) compared with 15 patients (23%) in the LD group (P = 0.246). Both secondary outcomes occurred in 12 patients (46%) in the SD group compared with 18 patients (27%) in the LD group (P = 0.086). Adjusted logistic regression analysis showed SD was not significantly associated with primary outcome [OR 1.12 (95% CI 0.38-3.31)] or secondary outcomes [OR 1.67 (95% CI 0.60-4.66)].

CONCLUSIONS

This single-centre experience did not demonstrate significant difference in outcomes between antibiotic duration of <4 weeks and ≥4 weeks in DFI patients with culture-positive proximal bone specimen post-amputation. These data provide background for larger international randomized control trials to establish optimal treatment duration.

Microbiology of diabetic foot osteomyelitis - Is it geographically variable?

INTRODUCTION

Diabetic foot osteomyelitis (DFO) is a dreaded complication as both diagnosis and treatment of the condition is laborious. However, for proper decision on antibiotics in medical management of DFO, accurate determination of microbes is necessary to narrow the spectrum of coverage and to reduce adverse effects of long-term administration of antibiotics. With differing pattern of use of antimicrobials and their resistance pattern in different countries, it is empirical to determine the microbiological characteristics of bone cultures in DFO from a referral institute in South India.

MATERIALS AND METHODS

This study was a retrospective chart review of all cases of proven DFO who had consented for debridement and bone culture or those who underwent amputation. Both deep soft tissue (DST) and bone cultures were obtained for aerobic bacteria. Clinical characteristics and site(s) of DFO were recorded. Investigations for peripheral artery disease were performed if clinically indicated.

RESULTS

In all, 105 patients with DFO were reviewed. Mean age was 62 years and 70% were men. Of those who were screened, 57% had evidence of peripheral arterial disease by arterial doppler. 46% of bone culture samples were sterile. Gram- negative organisms were more common (58%). Following staphylococcus, pseudomonas was the second common isolate. Of total staphylococcal isolates 37% were MRSA and 33% of klebsiella isolates were ESBL producing. Concordance rate between DST and bone cultures was 66%. 90% were mono-bacterial isolates. The commonest site of involvement of DFO was terminal phalanges of toes rather than base of 1st metatarsal.

CONCLUSION

Widespread use of antibiotics, tropical climate and route of entry of organisms causing DFO differed in our cohort of patients. Further studies from different regions of world would shed light onto different pattern of microbes causing DFO.

The value of administering intravenous antibiotics during haemodialysis in the treatment of diabetic foot infections

OBJECTIVE

People with diabetes who are on haemodialysis (HD) are at a high risk of diabetic foot infections (DFI) and related complications. We explored the value of treating DFI with intravenous (IV) antibiotics during HD.

METHOD

This was an observational study of consecutively treated patients with DFIs with IV antibiotics during HD. Data collected included baseline characteristics, IV antibiotics used, details of multidisciplinary interventions and DFI treatment outcome.

RESULTS

A cohort of 11 patients, mean (±standard deviation) age 62.4±12.7 years, had 15 episodes of treatment with IV antibiotics during HD. Of the patients, six (54.5%) were male and nine (81.8%) had type 2 diabetes. The estimated mean glomerular filtration rate (eGFR) was 11.4±3.9ml/minute. All patients had infected foot ulceration, soft tissue infection, six (54.5%) patients had osteomyelitis, and two (18.2%) had wet gangrene. The commonest IV antibiotic used was vancomycin (10/15 episodes, 66.7%). Other IV antibiotics used were daptomycin and meropenem. In three episodes, oral ciprofloxacin was used with IV antibiotics. The mean duration of antibiotic treatment was 9.2±4.9 weeks. Of the episodes, 11 (73.3%) were treated successfully with IV antibiotics alone and two (13.3%) episodes required minor surgical debridement/amputation. Some 10 (90.9%) members of the cohort had peripheral arterial disease and of those, five (50%) underwent angioplasty during IV antibiotic treatment.

CONCLUSION

HD provides a good opportunity for treatment with IV antibiotics in DFI. This mode of administration of IV antibiotics, along with multidisciplinary intervention, is associated with ulcer healing and resolution of infection in over three-quarters of patients with DFI.

DECLARATION OF INTEREST

The authors have no conflicts of interest to declare.

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.

Skeletal infections: microbial pathogenesis, immunity and clinical management

Osteomyelitis remains one of the greatest risks in orthopaedic surgery. Although many organisms are linked to skeletal infections, Staphylococcus aureus remains the most prevalent and devastating causative pathogen. Important discoveries have uncovered novel mechanisms of S. aureus pathogenesis and persistence within bone tissue, including implant-associated biofilms, abscesses and invasion of the osteocyte lacuno-canalicular network. However, little clinical progress has been made in the prevention and eradication of skeletal infection as treatment algorithms and outcomes have only incrementally changed over the past half century. In this Review, we discuss the mechanisms of persistence and immune evasion in S. aureus infection of the skeletal system as well as features of other osteomyelitis-causing pathogens in implant-associated and native bone infections. We also describe how the host fails to eradicate bacterial bone infections, and how this new information may lead to the development of novel interventions. Finally, we discuss the clinical management of skeletal infection, including osteomyelitis classification and strategies to treat skeletal infections with emerging technologies that could translate to the clinic in the future.

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.

Synthesis and Biological Evaluation of Novel Cinnamic Acid-Based Antimicrobials

The main antimicrobial resistance (AMR) nosocomial strains (ESKAPE pathogens such as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are the most widespread bacteria in cutaneous infections. In this work we report the synthesis, in silico skin permeability prediction, antimicrobial, antibiofilm, and wound healing properties of novel cinnamic acid-based antimicrobials (DM1–11) as novel antibacterial drugs for the treatment of ESKAPE-related skin infections. Antimicrobial and wound healing scratch assays were performed to evaluate the antibacterial properties of DM1–11. In silico skin permeability capabilities of DM1–11 were evaluated using Swiss-ADME online database. Cytotoxicity assays were performed on keratinocytes and fibroblasts. DM2, bearing a catechol group on the aromatic ring of the cinnamic portion of the molecule, possesses a significant antibacterial activity against S. aureus (MIC range 16–64 mg/L) and contrasts the biofilm-mediated S. epidermidis infection at low concentrations. Wound healing assays showed that wound closure in 48 h was observed in DM2-treated keratinocytes with a better healing pattern at all the used concentrations (0.1, 1.0, and 10 µM). A potential good skin permeation for DM2, that could guarantee its effectiveness at the target site, was also observed. Cytotoxicity studies revealed that DM2 may be a safe compound for topical use. Taking together all these data confirm that DM2 could represent a safe wound-healing topical agent for the treatment of skin wound infections caused by two of main Gram-positive bacteria belonging to ESKAPE microorganisms.

Long-term Mortality of a Cohort of Patients Undergoing Surgical Treatment for Diabetic Foot Infections. An 8-year Follow-up Study

We analyzed a retrospective cohort of 150 patients with diabetic foot infections (DFIs) who underwent surgical treatment to determine long-term outcomes. The median follow-up of the series was 7.6 years. Cox's proportional hazards model for survival time was performed and hazard ratios (HRs) were estimated. Survival times were plotted using the Kaplan-Meier method. Fifteen patients (10%) required readmission after discharge from the hospital for a recurrence of the infection. Ninety patients (60%) had re-ulcerations. Forty-nine (54.4% of those re-ulcerated) required new admission and 24 of them (26.6% of those re-ulcerated) finally required a new amputation. Overall cumulative survival rates at 1, 5, and 8 years were 95%, 78%, and 64%, respectively. Predictive variables of long-term mortality were insulin treatment (HR: 2.0, 95% CI: 1.1-3.6, P = .01), female sex (HR: 3.1, 95% CI: 1.7-5.3, P<.01) and estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² (HR: 2.2, 95% CI: 1.1-4.2, P = .01). In conclusion, patients undergoing surgical treatment for DFIs had a high rate of recurrences and mortality. Women, patients who underwent treatment with insulin, and those with eGFR <60 ml/min/1.73 m² had a higher risk of long-term mortality.

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.

Interplay between ESKAPE Pathogens and Immunity in Skin Infections: An Overview of the Major Determinants of Virulence and Antibiotic Resistance

The skin is the largest organ in the human body, acting as a physical and immunological barrier against pathogenic microorganisms. The cutaneous lesions constitute a gateway for microbial contamination that can lead to chronic wounds and other invasive infections. Chronic wounds are considered as serious public health problems due the related social, psychological and economic consequences. The group of bacteria known as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp.) are among the most prevalent bacteria in cutaneous infections. These pathogens have a high level of incidence in hospital environments and several strains present phenotypes of multidrug resistance. In this review, we discuss some important aspects of skin immunology and the involvement of ESKAPE in wound infections. First, we introduce some fundamental aspects of skin physiology and immunology related to cutaneous infections. Following this, the major virulence factors involved in colonization and tissue damage are highlighted, as well as the most frequently detected antimicrobial resistance genes. ESKAPE pathogens express several virulence determinants that overcome the skin's physical and immunological barriers, enabling them to cause severe wound infections. The high ability these bacteria to acquire resistance is alarming, particularly in the hospital settings where immunocompromised individuals are exposed to these pathogens. Knowledge about the virulence and resistance markers of these species is important in order to develop new strategies to detect and treat their associated infections.

Predictors of healing, ulcer recurrence and persistence, amputation and mortality in type 2 diabetic patients with diabetic foot: a 10-year retrospective cohort study

PURPOSE

Predictors of outcome of diabetic foot ulcer (DFU) are important to improve the management of patients. Aim of the study was to find these predictors in type 2 diabetic patients with DFU.

METHODS

We recruited 583 patients. They were followed-up by a multidisciplinary team. A holistic and conservative approach was used and all risk factors and co-morbidities were aggressively treated.

RESULTS

During the follow-up period, 79.6% of patients healed in a mean time of 7.6 ± 3.8 months, 6.9% showed DFU persistence, 9.9% had minor amputations, and 3.6% experienced major amputation. Seventeen percent of the patients died. Among patients who healed, 37.1% of them showed DFU recurrence. Impairment of renal function was associated to DFU persistence, amputation, and mortality. Previous cardiovascular disease predicted DFU persistence, DFU recurrence, and mortality. Lower BMI predicted DFU persistence and mortality. Osteomyelitis was a predictor of amputation and death. Markers of peripheral artery disease (PAD) predicted minor amputation and DFU recurrence. Our study shows a relatively low incidence of complications of DFU.

CONCLUSIONS

Some predictors of outcome of DFU were confirmed and new predictors, like BMI and markers of PAD, were found. Our new findings suggest future strategies for nutrition support and revascularization. In addition, a holistic and conservative approach may improve the prognosis.

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.

Evolutionary trends in bacteria isolated from moderate and severe diabetic foot infections in a Portuguese tertiary center

INTRODUCTION

Diabetic Foot infections (DFI) are a major cause of hospitalization in patients with diabetes. The microbiological study of diabetic ulcers is essential to adequate antibiotic therapy and to minimize the selection of resistant microorganisms. The aim of this study was to characterize and to compare the evolution of isolated microorganisms between the biennium 2010-2011 and 2016-2017, in hospitalized patients with DFI.

MATERIAL AND METHODS

Retrospective evaluation of the clinical and analytical data of patients who were admitted due to DFI in 2010-2011 (group 2010/11) and 2016-2017 (group 2016/17). Only the first hospitalization for each patient was included. An adequate descriptive and comparative statistical analysis was performed.

RESULTS

There were 274 admissions due to DFI, 151 in 2010/11 and 123 in 2016/17. There was an increase in admissions due to neuroischemic DFI (51.0% in 2010/11 to 61.8% in 2016/17, p = 0.048). Staphylococcus aureus (SA) was the most common isolate in 2010/11 (26.7%). In 2016/17 most cultures were mixed polymicrobial and isolation of Enterobacteriaceae and Pseudomonas aeruginosa increased from 2010/11 to 2016/17 (15.9% to 30.6%, p = 0.001, and 9.1% to 13.7%, p = 0.048, respectively).

CONCLUSION

There was an increase in the prevalence of neuroischemic DFU. The Enterobacteriaceae family replaced SA as the most prevalent pathogen in DFI, with an increase in the isolation of gram-negative microorganisms and mixed polymicrobial cultures. Chronic neuroischemic infected ulcers usually present distinct bacterial isolates; knowledge about the most common agents is warranted in order to better select empiric antibiotic therapy.

Adjunctive Rifampin Therapy For Diabetic Foot Osteomyelitis in the Veterans Health Administration

IMPORTANCE

Among patients diagnosed with diabetes, the lifetime incidence of foot ulcers is 15%. Infection is a common complication of foot ulcers, and 20% to 60% of infections result in diabetic foot osteomyelitis (DFO). Current treatment guidelines do not endorse any specific antibiotic agent for DFO, but small clinical trials suggest the addition of rifampin to antimicrobial regimens results in improved cure rates for osteomyelitis.

OBJECTIVE

To compare the clinical outcomes of patients treated for DFO in the Veterans Health Administration (VHA) with and without adjunctive rifampin.

DESIGN, SETTING, AND PARTICIPANTS

This observational cohort study used VHA databases to identify index DFO cases from January 1, 2009, through December 31, 2013, and analyzed patients alive and without high-level amputation at 90 days after diagnosis in whom antibiotic therapy was initiated within 6 weeks of diagnosis. Patients with death or major amputation within 90 days of diagnosis, who were not treated with systemic antibiotics dispensed by the VHA within 6 weeks of diagnosis, or who were treated at facilities where rifampin was not dispensed for DFO were excluded. The retrospective cohort to inform the planning of a multisite randomized clinical trial was first investigated in spring 2015; retrospective analysis was performed from February 2017 through September 2019.

EXPOSURES

Patients initiating rifampin therapy within 6 weeks of the DFO diagnosis and receiving the drug for at least 14 days within 90 days of diagnosis were considered treated with rifampin. Patients not administered rifampin within 90 days of diagnosis served as the comparator group.

MAIN OUTCOMES AND MEASURES

A combined end point of mortality or amputation within 2 years of diagnosis was analyzed. Differences in times to event were evaluated using log-rank tests. Differences in event rates were compared using χ2 tests and multivariable logistic regression.

RESULTS

The analysis population included 130 patients treated with rifampin and 6044 treated without rifampin (total of 6174; 6085 men [98.6%]; mean [SD] age, 64.9 [9.7] years). Lower event rates were observed among the rifampin group (35 of 130 [26.9%] vs 2250 of 6044 [37.2%]; P = .02). Patients treated with rifampin were younger (mean [SD] age, 62.2 [9.4] vs 64.9 [9.6] years), had fewer comorbidities (mean [SD] Charlson comorbidity index score, 3.5 [1.8] vs 4.0 [2.2]), had more infectious disease specialty consultations (63 of 130 [48.5%] vs 1960 of 6044 [32.4%]), and more often had Staphylococcus aureus identified in cultures (55 of 130 [42.3%] vs 1755 of 6044 [29.0%]) than patients not treated with rifampin. A logistic regression estimating the odds of events and controlling for these and other covariates yielded a significant association of rifampin (odds ratio, 0.65; 95% CI, 0.43-0.96; P = .04).

CONCLUSIONS AND RELEVANCE

In this cohort study, patients administered rifampin experienced lower rates of death and amputation than patients not treated with rifampin, which remained significant after adjustment for confounders. These results coupled with existing evidence from small clinical trials suggest the addition of rifampin to current treatment regimens may be a useful antimicrobial option in the treatment of DFO.