1018. Bacterial Bioburden Characterization of Infected Diabetic Foot Ulcers in Hospitalized Patients in Association with Clinical Outcomes: Traditional Cultures vs. Molecular Sequencing Methods

Background Infected diabetic foot ulcers (IDFU) are a major complication of diabetes mellitus. These potentially limb-threatening ulcers are challenging to treat due to the impairment of wound healing in diabetic patients and the complex microbial environment characterizing these ulcers. Our aim was to analyze the microbiome of IDFU in association with clinical outcomes. Methods Wound biopsies from IDFU were obtained from hospitalized patients and were analyzed using traditional microbiology cultures, 16S rRNA sequencing and shotgun metagenomic sequencing. Patients’ characteristics, culture-based results and sequencing data were analyzed in association with clinical outcomes. Study Design Results 31 patients were enrolled. Significantly more anaerobic and Gram-negative bacteria were detected with sequencing methods compared to conventional cultures (59% and 76% were anaerobes according to 16SrRNA and metagenomic respectively vs. 26% in cultures, p=0.001, and 79%, 59% and 54% were Gram negative bacteria respectively, p< 0.001). Culture-based results showed that Staphylococcus aureus was more prevalent among patients who were conservatively treated (p=0.048). In metagenomic analysis the Bacteroides genus was more prevalent among patients who underwent toe amputation (p< 0.001). Analysis of metagenomic-based functional data showed that antibiotic resistance genes and genes related to biofilm production and to bacterial virulent factors were more prevalent in IDFU that resulted in toe amputation (p< 0.001). Occurrences and mean relative abundances of the most prevalent bacteria of IDFU Comparison between [A] traditional cultures, 16S rRNA sequencing and metagenomic sequencing results (genera level - 12 samples) [B] traditional cultures and metagenomic sequencing results (species level – 30 samples) [C] traditional cultures and 16S rRNA sequencing results (genera level - 30 samples) CUL – cultures; 16S - 16S rRNA sequencing; MTG – metagenomic sequencing Bacteroides genus association with toe amputation Bacteroides genera was more common among samples of patients who underwent toe amputation compared with samples of patients who were conservatively treated (p < 0.001). Species level analysis showed that Bacteroides fragilis and Bacteroides xylanisolvens predominated IDFU of patients who underwent toe amputation (p=0.04, p=0.002 respectively). No – conservative treatment; Yes – toe amputation. Functional genes differentiating patients who underwent toe amputation from conservatively treated Yellow stars – indicate genes that were associated with bacterial virulent factors, biofilm formation and resistant mechanisms – all were more prevalent in patients who underwent toe amputation (with p values<> Conclusion Molecular sequencing tools uncover the complex biodiversity of IDFU and emphasize the high prevalence of anaerobes and Gram-negative bacteria in these ulcers. Furthermore, sequencing results highlighted the possible association between certain genera, species, and bacterial functional genes to clinical outcomes Disclosures Yossi Paitan, PhD, Ilex Medical Ltd (Employee, Other Financial or Material Support, As of 01.01.2021 I am the Laboratories Manager of Ilex Labs)

1447 Trends in Lower Extremity Amputation Incidence in European Union 15+ Countries 1990-2017

Aim To assess trends in lower extremity amputation (LEA) incidence in European Union (EU15+) countries for the years 1990-2017. Method This was an observational study using data obtained from the 2017 Global Burden of Disease (GBD) Study. Age standardised incidence rates (ASIRs) for LEA (stratified into toe amputation, and LEA proximal to toes) were extracted from the GBD Results Tool (http://ghdx.healthdata.org/gbd-results-tool) for EU15+ countries for each of the years 1990-2017. Trends were analysed using Joinpoint regression analysis. Results Between 1990 and 2017, variable trends in the incidence of LEA were observed in EU15+ countries. For LEAs proximal to toes, increasing trends were observed in six of 19 countries and decreasing trends in nine of 19 countries, with four countries showing varying trends between sexes. For toe amputation, increasing trends were observed in eight of 19 countries and decreasing trends in eight of 19 countries for both sexes, with three countries showing varying trends between sexes. Australia had the highest ASIRs for both sexes in all LEAs at all time points, with steadily increasing trends. The USA observed the greatest reduction in all LEAs in both sexes over the time period analysed (LEAs proximal to toes: female patients 22.93%, male patients 29.76%; toe amputation: female patients 29.93%, male patients 32.67%). The greatest overall increase in incidence was observed in Australia. Conclusions Variable trends in LEA incidence were observed across EU15+ countries. These trends do not reflect previously observed reductions in incidence of PAOD over the same time period.

Intraadiposal Pedicle Dissection when Performing Free Tissue Transfer: A Means to Address a Short Pedicle

A 77-year-old male patient with a diabetic foot ulcer on his right great toe visited the outpatient clinic. As necrosis of the toe had already progressed, the patient underwent toe amputation to prevent extensive gangrene. With the goal of enabling future ambulation, an anterolateral thigh fasciocutaneous free flap was planned to preserve the metatarsal head and to cover the defect. Subfascial dissection was performed when elevating the fasciocutaneous flap, but the sole healthy perforator was in an extremely proximal area and allowed only a 4-cm-long pedicle. The pedicle had to be at least 8 cm long to ensure secure anastomosis to the medial plantar artery. To overcome this unexpected challenge, we pierced the deep fascia near the perforator and dissected the perforator distally within the deep adipose layer. The necessary additional length of the pedicle was obtained through intraadiposal dissection. The flap survived without any complications, and the foot was reconstructed with successful ambulation. This case demonstrates the value of attempting intraadiposal pedicle dissection when the pedicle turns out to be unmanageably short.

A Meta-analysis of the Types and Outcomes of Conservative Excisional Surgery for Recalcitrant or Infected Diabetic Toe Ulcers

Although they occur frequently, diabetic toe ulcers (DTUs) are poorly investigated. Long-term antibiotics or toe amputation are the usual indications for complicated DTU treatment. Some authors reported good to excellent results following conservative surgery (CS) for recalcitrant or infected wounds; yet no systematic review has been published. Seven studies, comprising 290 patients with 317 ulcers, met the inclusion criteria of this meta-analysis. Three types of CS were found: resection arthroplasty of the interphalangeal joint, toe-sparing bone excision (internal pedal amputation), and distal Symes amputation. The meta-analytical results were as follows: healing rate of 98.3%, healing time of 6.8 ± 3.9 weeks, recurrence rate of 2.3%, wound dehiscence/recurrent infection rate of 6.4%, skin necrosis rate of 2.8%, and revision surgery rate of 7.4%. Subgroup analyses showed no significant differences in outcomes between recalcitrant ulcers and infected ulcers nor between surgery types. Significance was found in relation to ulcer location; when compared with the hallux, DTU on the lesser toes demonstrated better outcomes. Compared with the reported overall results of standard of care associated with antibiotics or toe amputation of complicated DTUs in the literature, CS seems to be a better option for the treatment of recalcitrant or infected DTUs. Levels of Evidence: Level III

Healing and Mortality Rates Following Toe Amputation in Type 2 Diabetes Mellitus

Background and Aim This single-centre study aimed to determine healing, re-ulceration, re-amputation and mortality rates at one year after toe amputations in patients with type 2 diabetes (T2DM). Patients and Methods Eighty-one participants with T2DM admitted for toe amputation were included. Patient characteristics, peripheral circulation and neuropathy status were recorded. Subjects were then followed every 3 months post-amputation for a year. Results Overall, 59.3% of participants underwent further surgery (n=31 to revise the original amputation site and n=17 to amputate a new site). During 12 months, 45.7% of participants presented with a new ulcer at a different site. Mortality was 7.4%. In 12.4% of participants, the amputation site remained incompletely healed. Only 20.9% had no complications in 12 months. At 12 months, 80.2% of study cohort had a completely healed amputation site. Conclusion In conclusion, this study highlighted high re-intervention, re-amputation and new ulceration rates. Strategies to improves these outcomes in such high-risk patients are warranted.