MALDI-TOF MS Based Bacterial Antibiotics Resistance Finger Print for Diabetic Pedopathy

Diabetes mellitus has become a major global health issue. Currently, the use of antibiotics remains the best foundational strategy in the control of diabetic foot infections. However, the lack of accurate identification of pathogens and the empirical use of antibiotics at early stages of infection represents a non-targeted treatment approach with a poor curative effect that may increase the of bacterial drug resistance. Therefore, the timely identification of drug resistant bacteria is the key to increasing the efficacy of treatments for diabetic foot infections. The traditional identification method is based on bacterial morphology, cell physiology, and biochemistry. Despite the simplicity and low costs associated with this method, it is time-consuming and has limited clinical value, which delays early diagnosis and treatment. In the recent years, MALDI-TOF MS has emerged as a promising new technology in the field of clinical microbial identification. In this study, we developed a strategy for the identification of drug resistance in the diagnosis of diabetic foot infections using a combination of macro-proteomics and MALDI MS analysis. The macro-proteomics result was utilized to determine the differential proteins in the resistance group and the corresponding peptide fragments were used as the finger print in a MALDI MS analysis. This strategy was successfully used in the research of drug resistance in patients with diabetic foot infections and achieved several biomarkers that could be used as a finger print for 4 different drugs, including ceftazidime, piperacillin, levofloxacin, and tetracycline. This method can quickly confirm the drug resistance of clinical diabetic foot infections, which can help aid in the early treatment of patients.

Diabetic Foot Ulcer Infections and Pseudomonas aeruginosa Biofilm Production During the COVID-19 Pandemic

During the different waves of the coronavirus (COVID-19) pandemic, there has been an increased incidence of diabetes mellitus and diabetic foot infections. Among gram-negative bacteria, Pseudomonas aeruginosa is the predominant causative agent for diabetic foot ulcer infections in low-resource countries. P. aeruginosa possesses a variety of virulence factors, including biofilm formation. Biofilm formation is an important benchmark characteristic in the pathophysiology of diabetic foot ulceration. The main objective of the current study was to identify the most commonly isolated organisms and their antibiotic susceptibility patterns in diabetic foot patients during the COVID-19 pandemic. We also determined the genes associated with bacterial persistence and biofilm formation in the predominantly isolated organism. Accordingly, 100 wound swab samples were collected from diabetic foot patients from different hospitals in Alexandria, Egypt. Through phenotypic detection of biofilm formation, 93% (40) of the 43 P. aeruginosa isolates examined were categorized as biofilm producers. Molecular detection of the biofilm-encoding genes among the 43 P. aeruginosa isolates was as follows: algD (100%), pelF (88%) and pslD (49.7%), and this highlights a need for biofilm formation inhibitors to prevent the persistence of bacterial pathogens, and thus achieve better clinical outcomes in diabetic foot ulcer infections.

The Association between Foot Surgery Type and Subsequent Healing in Veterans with Moderate-to-Severe Diabetic Foot Infections

Background Diabetic foot infections are a common precursor to lower extremity amputations. The treatment of diabetic foot infections involves both medical and surgical management, of which limb-sparing surgeries are increasingly preferred over amputations at or above the ankle to preserve mobility and quality of life. The outcomes following these limb-sparing surgeries are not well-described. Methods This was a single-center, retrospective cohort study of 90 Veterans with moderate-to-severe diabetic foot infections between 2017 and 2019 from the VA Maryland Health Care System. The exposure was foot surgery with bone resection (i.e., toe amputation, metatarsal resection, transmetatarsal amputation) versus debridement alone. The outcome was healing within 1 year. We used log-binomial regression to assess the association between foot surgery type and healing, stratify by infection location, and evaluate potential confounding variables. Results The cumulative incidence of healing after foot surgery with bone resection was greater than that following debridement (risk ratio 1.80, 95% confidence interval [1.17, 2.77]). This association was modified by infection location and greater for toe infections (4.52 [1.30, 15.7]) than other foot infections (1.19 [0.69, 2.02]). We found no evidence of confounding by comorbidities or infection severity. Conclusions For patients with toe infections, foot surgery with bone resection was associated with better healing than debridement alone. The multiple specialties caring for patients with diabetic foot infections need a stronger common knowledge base—from studies like this and future studies—to better counsel patients about their treatment and prognosis.

Association Between Dermcidin, Salusin-α, Salusin-β Molecules and Diabetic Foot Infections

Dermcidin, salusin-α, and salusin-β are three recently discovered molecules that confer antimicrobial properties. The present study aims to investigate the association between dermcidin, salusin-α, and salusin-β in the etiopathology of patients with diabetic foot infection. The study included three groups: Group 1 - diabetic foot infection; Group 2 - diabetes without history of diabetic foot; and Group 3 – the control group. Plasma dermcidin, salusin-α, and salusin-β levels were compared across the groups. Median (Q1-Q3) values of plasma dermcidin levels in Groups 1, 2, and 3 were 3.45 (0.8-4.4), 5.2 (3.7-6.4), and 5.8 (3.1-10) ng/mL, respectively. Diabetic foot infection group had significantly lower plasma dermcidin levels compared to diabetes only group and control group ( P = .000, ANOVA), whereas there was no statistically significant difference between the Group 2 and Group 3 ( P = .163, ANOVA). Salusin-α and salusin-β levels were significantly higher in the Group 3 compared to the other groups. Based on our findings, diabetic foot infection group had significantly lower plasma dermcidin levels and salusin-α and salusin-β levels were significantly higher in the control group. These molecules (dermcidin specifically) can be researched as an adjuvant therapeutic agent in addition to conventional treatments in diabetic foot diabetic foot infections. Also, it can be searched this may prevent many complications including amputation.

Case Report on Cellulitis with Diabetes

Introduction: Cellulitis is a bacterial skin condition that is very frequent. In reality, cellulitis affects about 14 million people in the United States each year. If left untreated, the infection can spread to any part of the body and cause serious problems. Obesity and an inactive lifestyle are two of the most common causes of type 2 diabetes. Clinical Findings: Pain or tenderness in the leg, Skin redness or inflammation that gets bigger as the infection spreads, Skin sore or rash that starts suddenly, and grows quickly , Warm skin. Diagnostic Evaluation: Hb%- 10.7, MCHC- 33.4, MCV- 88.8, MCH- 29.8, Total RBC count- 3.6, Total WBC count- 7200, Total platelets count - 1.63, HCT- 37, Monocytes- 01, Granulocytes- 75, Lymphocytes - 20, RDW - 17.2, Eosinophils - 01. Therapeutic Interventions: Inj. Ceftriaxone 1mg x BD (IV), Inj. Pan 40 mg x OD (IV), Tab. Limcee 500 mg x OD, Tab. Pan 40 mg x OD, Protein powder 2 tsp x TDS, Inj. Insulin. Outcomes: A Male Patient of 88 year old was admitted in AVBRH with a chief Complaint of Cellulitis after getting treatment his condition is improving. Conclusion: Diabetic foot infections that aren't treated well or aren't treated at all result in lower-extremity amputation in about 10% of patients. Amputations of the lower extremities can be debilitating and have a significant impact on the patient's quality of life.

Influence of Nisin-Biogel at Subinhibitory Concentrations on Virulence Expression in Staphylococcus aureus Isolates from Diabetic Foot Infections

A new approach to diabetic foot infections (DFIs) has been investigated, using a nisin-biogel combining the antimicrobial peptide (AMP) nisin with the natural polysaccharide guar-gum. Since in in vivo conditions bacteria may be exposed to decreased antimicrobial concentrations, known as subinhibitory concentrations (sub-MICs), effects of nisin-biogel sub-MIC values corresponding to 1/2, 1/4 and 1/8 of nisin’s minimum inhibitory concentration (MIC) on virulence expression by six Staphylococcus aureus DFI isolates was evaluated by determining bacteria growth rate; expression of genes encoding for staphylococcal protein A (spA), coagulase (coa), clumping factor A (clfA), autolysin (atl), intracellular adhesin A (icaA), intracellular adhesin D (icaD), and the accessory gene regulator I (agrI); biofilm formation; Coa production; and SpA release. Nisin-biogel sub-MICs decreased bacterial growth in a strain- and dose-dependent manner, decreased agrI, atl and clfA expression, and increased spA, coa, icaA and icaD expression. Biofilm formation increased in the presence of nisin-biogel at 1/4 and 1/8 MIC, whereas 1/2 MIC had no effect. Finally, nisin-biogel at sub-MICs did not affect coagulase production, but decreased SpA production in a dose-dependent manner. Results highlight the importance of optimizing nisin-biogel doses before proceeding to in vivo trials, to reduce the risk of virulence factor’s up-regulation due to the presence of inappropriate antimicrobial concentrations.

Wound Myiasis in Diabetic Foot Ulcer: Calliphoridae and Sar-cophagidae Family

Background: Myiasis is a parasitic infestation of tissues or body cavities of mammals with dipterous larvae. The patients with diabetic foot ulcers are more vulnerable to acquiring infestation; however, the infestation may be neglected and mistreated in some cases. Methods: Data were collected of twelve myiasis cases with diabetic foot ulcers in Nazli-Selim Eren Chronic Wound and Infections Care Unit, Aydin, Turkey between 2017 and 2019. Demographic, clinical characteristics of the patients and clinical examination of the wound were recorded. To morphology-based identification method of the agents, the developmental stages of the maggots were examined. Results: The cases aged between 46 and 81 years (10 males, two females). Eight of the larvae collected from wounds had Calliphoridae and four had Sarcophagidae family. The larvae were infested right/left foot sole, thumb, ankle, and mostly left toes. The number of larvae collected from the cases ranged from 2 to 48. Third-stage larvae (L3) were mostly detected. Mixed (L1-L2, L2-L3) larvae were detected in a patient. The infestations were more common in July and August. According to the score of Infectious Diseases Society of America (IDSA), ten (83%) cases had moderate and two (17%) cases were mild diabetic foot infections (DFIs). Conclusion: Diabetic foot ulcers should be evaluated in terms of myiasis. This was the first study in our province indicating that myiasis should not be neglected and different species of flies were responsible for myiasis cases.

Microbiological and Antimicrobial Pattern of Diabetic Foot Ulcers at a Tertiary Care Center in East China

Background Diabetic foot infections (DFIs) are the most complex and challenging pathological state, characterized by high complexity of management, morbidity, and mortality. Empirical antimicrobial administration is needed before the identification of the causative organisms. Microbiological profile of the diabetic foot patients is the basis of the antibiotic choice for clinicians. Methods 76 patients visiting the Diabetic Foot Center of our Hospital for having ulcers with Wagner 3 to 5 were retrospectively surveyed for the bacterium infected. Antimicrobial susceptibility testing (AST) was implemented and the results were interpreted on the basis of the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results A total of 92 isolates were obtained, of which 47 strains of gram-negative bacilli (GNB) accounted for 51.1%, 41 strains of gram-positive cocci (GPC) accounted for 44.6%, and 4 strains of fungi accounted for 4.3%. Species of Enterobacteriaceae and Staphylococcus are the two predominant strains. The top 4 most frequently isolated strains were Staphylococcus aureus (22.8%), enterococcus faecalis (9.8%), Pseudomonas aeruginosa (9.8%), Escherichia coli (5.4%). The rate of resistance to methicillin was 33.3% for S. aureus. The rate of extended-spectrum β-lactamases (ESBLs) production among E. coli was 60%. 50% of Klebsiella pneumoniae were resistant to carbapenems. P. aeruginosa showed high sensitivity to commonly used antibiotics. There was one isolate of Acinetobacter spp. resistant to most antimicrobials except tigecycline and aminoglycosides. Conclusion Enterobacteriaceae and Staphylococcus are the two predominant species. The resistance to antibiotics of S. aureus and P. aeruginosa showed optimistic results. However, the high prevalence of CRKP imposed a challenging issue for clinical physicians.

110. MRSA nasal swab as a stewardship tool to guide IV Vancomycin in diabetic foot infections

Background The Infectious Disease Society of America (IDSA) guidelines suggest empiric Methicillin-Resistant Staphylococcus Aureus (MRSA) coverage for Diabetic Foot Infection (DFI) with a history of MRSA infection, if local prevalence is high, or if the infection is severe. However, data suggests that there is overutilization of vancomycin in this population and this medication is associated with toxicity. MRSA nasal screen has a high negative predictive value (NPV) for ruling out MRSA in pneumonia and other sites. We performed a medication utilization evaluation (MUE) for Vancomycin IV in DFI patients who had an MRSA nares screen to determine our own NPV of this test and feasibility to use it as an antibiotic stewardship program (ASP) tool to guide vancomycin use in this population. Methods We retrospectively reviewed 224 patients from January 2015 to January 2020 who had a diagnosis of DFI and an MRSA nasal screen. 139 patients had cultures done. For the NPV, we excluded patients who had any MRSA positive culture or screen up to a year from admission (Figure 1). Figure 1. Flowchart from our medication utilization evaluation showing patient’s distribution by MRSA-screen result Results We found 148 (66%) patients with DFI who had received IV vancomycin empirically during the admission and 196 of them were MRSA-nares negative (Figure 2). The average days of therapy (DOT) in the MRSA-nares negative patients was 5.2 days vs 4.8 in the MRSA-nares positive patients. Out of the 139 patients with a negative MRSA nasal swab, 124 had no MRSA in cultures, yielding an NPV of 89%. If we considered only the deep cultures, the NPV increased to 90%. Figure 2. Number of patients who received IV vancomycin grouped by MRSA-screen result Conclusion We identified overutilization of IV vancomycin in patients with a diagnosis of DFI in our institution. Also, our NPV of the MRSA-nasal screening to rule out MRSA infection in DFI was high at 89% similar to previous studies. Based on these findings, we plan to implement a local ASP protocol (Figure 3) using MRSA nasal swab screen to decrease the empiric use of vancomycin. The results of these efforts will be analyzed and published in future iterations with the hopes to share this knowledge to reduce the use of IV vancomycin in this population in other centers. Figure 3. Protocol draft to be used as an ASP tool to guide IV vancomycin de-escalation based on MRSA-nasal screen for DFI patients Disclosures All Authors: No reported disclosures