Bacterial Bioburden Research Articles

Therapeutic Indices of Topical Antiseptics in Wound Care: A Systematic Review.

Chronic wounds place a heavy burden on healthcare systems and markedly reduce the ability of patients to engage in activities of daily living. One major factor contributing to impaired wound healing is bacterial bioburden. With the rise in antibiotic resistance and the slowdown in antibiotic development pipelines, alternative antimicrobial strategies are important. The objective of this systematic review is to determine the topical antiseptic therapeutic index values for bacterial species commonly isolated from chronic wounds. The therapeutic index is a ratio of the lowest concentration that causes mammalian cell cytotoxicity over the minimum bactericidal concentration. Higher values indicate greater safety and potential clinical benefit. A systematic literature search was performed in Medline and Embase, resulting in the inclusion of 37 articles that reported on the minimum bactericidal concentration in bacterial species commonly isolated from chronic wounds and their cytotoxicity concentrations in mammalian cells. The therapeutic indices for the topical antiseptics included in this study were generally low, with most ranging between 0.5-3.0. The highest therapeutic index values for Escherichia coli (5.49), Staphylococcus aureus (6.31) and Pseudomonas aeruginosa (8.81) were achieved by hypochlorous acid, whereas the highest therapeutic index values for methicillin resistant S aureus (12.1) was achieved by polyhexamethylenebiguanide. Antibiotic stewardship principles may need to be applied to topical antiseptics due to some isolated evidence of topical antiseptic resistance and cross-resistance to antibiotics. The choice of antiseptic should not be made solely based on therapeutic index values, but individualized to the patient, with consideration for the wound healing condition that may include covert infection.

Immobilization of biosynthesized gallium nanoparticles in Polyvinylpyrrolidone/Sodium alginate films: Potent bactericidal protection against food spoilage bacteria

The increasing threat of spoilage bacterial infections, driven by the resistance of bacteria to many antimicrobial treatments, is a significant worldwide public health problem, especially concerning food preservation. To tackle these difficulties, this research investigates the possibility of using packaging sheets that include antimicrobial agents and increasing the prolonged storage time by preventing the bioburden of foodborne pathogens. This approach uses metal nanoparticles' ability to prevent harmful bacteria that cause food spoiling. Gallium nanoparticles (GaNPs) were created using a water-based extract from Andrographis paniculata leaves as a bioreducing agent. The GaNPs were added to a film made of sodium alginate (SA) and polyvinylpyrrolidone (PVP). The study showed that incorporating GaNPs into polymer films resulted in films with a desirable contact angle and decreased water vapor permeability. Significantly, the developed films demonstrated increased efficiency against E.coli O157 compared to other species. Also, it exhibited increased vulnerability to bacterial strains at the biofilm stage, surpassing PVP-SA/GaNPs-0. Remarkably, the toxicity tests showed that the films exhibited no cytotoxicity. Overall, the films indicated their potential for avoiding bacterial bioburden, prolonging the shelf life of perishable products, and contributing to diverse antimicrobial applications in the food industry.

Oral health status of Egyptian children with lysosomal storage diseases: An evaluation of dental indices, salivary cytokines level, and bacterial bioburden.

Lysosomal storage diseases (LSDs), a group of inborn errors of metabolism, include various subtypes, for example, mucopolysaccharidosis (MPS) and Gaucher disease (GD). Besides the physical/mental disabilities, they suffer from several oral deteriorations. To evaluate the oral health status of Egyptian children with LSD. Thirty LSD children and thirty non-LSD children were enrolled for this study according to the inclusion and exclusion criteria. Dental indices were used to assess caries prevalence and periodontal status. Saliva samples were collected from all enrolled children to estimate interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), and protein levels as well as Streptococcus mutans and Lactobacilli colony counts. Children with MPS and GD showed non-significant differences in decayed, missing, or filled teeth (DMFT) scores (p = .115). Scores of dmft showed a significant increase in MPS, but not in GD children (p = .020, p = .127). Children with LSD showed significantly increased Modified Gingival Index (MGI), Plaque Index (PI), Oral Hygiene Index (OHI-s) scores (p < .001) and salivary IL-6 and TNF-α (p = .007, p = .001, p < .0001, p = .002, respectively) and salivary total proteins (p = .001) levels. Unexpectedly, non-significant differences were observed in salivary Streptococcus mutans or Lactobacilli counts in children with MPS and GD (p = .058, p = .420, p = .502, p = .053, respectively). To our knowledge, this is the first article that evaluates Egyptian children with LSD. We demonstrated high caries prevalence in primary teeth, not permanent teeth, in children with MPS and poor gingival/hygiene status in children with MPS and GD, which triggered a state of inflammation. The daily supplement intake prevented oral bacterial growth. The most probable cause of oral alterations is decreased salivary flow rate, as deduced from a significantly increased salivary protein.

Bioarchitectural Design of Bioactive Biopolymers: Structure-Function Paradigm for Diabetic Wound Healing.

Chronic wounds such as diabetic ulcers are a major complication in diabetes caused by hyperglycemia, prolonged inflammation, high oxidative stress, and bacterial bioburden. Bioactive biopolymers have been found to have a biological response in wound tissue microenvironments and are used for developing advanced tissue engineering strategies to enhance wound healing. These biopolymers possess innate bioactivity and are biodegradable, with favourable mechanical properties. However, their bioactivity is highly dependent on their structural properties, which need to be carefully considered while developing wound healing strategies. Biopolymers such as alginate, chitosan, hyaluronic acid, and collagen have previously been used in wound healing solutions but the modulation of structural/physico-chemical properties for differential bioactivity have not been the prime focus. Factors such as molecular weight, degree of polymerization, amino acid sequences, and hierarchical structures can have a spectrum of immunomodulatory, anti-bacterial, and anti-oxidant properties that could determine the fate of the wound. The current narrative review addresses the structure-function relationship in bioactive biopolymers for promoting healing in chronic wounds with emphasis on diabetic ulcers. This review highlights the need for characterization of the biopolymers under research while designing biomaterials to maximize the inherent bioactive potency for better tissue regeneration outcomes, especially in the context of diabetic ulcers.

Development of a two-dimensional peptide functionalized-reduced graphene oxide biomaterial for wound care applications.

Increased incidences of antibiotic resistance have necessitated the development of novel wound disinfection strategies with minimal risk of resistance development. This study aimed at developing a biocompatible wound dressing biomaterial with the potential to treat acute and chronic wounds infected with multidrug-resistant Pseudomonas aeruginosa. A multifunctional antibacterial nanoconjugate was synthesized by covalently coupling a synthetically designed peptide (DP1, i.e., RFGRFLRKILRFLKK) with reduced graphene oxide (rGO). The conjugate displayed antibacterial and antibiofilm activities against multidrug-resistant Pseudomonas aeruginosa. In vitro studies demonstrated 94% hemocompatibility of the nanoconjugate even at concentrations as high as 512 μg mL-1. Cytotoxicity studies on 3T3-L1 cells showed 95% cell viability, signifying biocompatibility. Owing to these properties, the biomedical applicability of the nanoconjugate was assessed as an antibacterial wound dressing agent. rGO-DP1-loaded wound dressing exhibited enhanced reduction in bacterial bioburden (6 log 10 CFU) with potential for wound re-epithelization (77.3%) compared to the uncoated bandage. Moreover, an improvement in the material properties of the bandage was observed in terms of enhanced tensile strength and decreased elongation at break (%). Collectively, these findings suggest that rGO-DP1 is an effective biomaterial that, when loaded on wound dressings, has the potential to be used as a facile, sustainable and progressive agent for bacterial wound disinfection as well as healing.

Chitosan-based multifunctional oxygenating antibiotic hydrogel dressings for managing chronic infection in diabetic wounds.

Current treatment strategies for infection of chronic wounds often result in compromised healing and necrosis due to antibiotic toxicity, and underlying biomarkers affected by treatments are not fully known. Here, a multifunctional dressing was developed leveraging the unique wound-healing properties of chitosan, a natural polysaccharide known for its numerous benefits in wound care. The dressing consists of an oxygenating perfluorocarbon functionalized methacrylic chitosan (MACF) hydrogel incorporated with antibacterial polyhexamethylene biguanide (PHMB). A non-healing diabetic infected wound model with emerging metabolomics tools was used to explore the anti-infective and wound healing properties of the resultant multifunctional dressing. Direct bacterial bioburden assessment demonstrated superior antibacterial properties of hydrogels over a commercial dressing. However, wound tissue quality analyses confirmed that sustained PHMB for 21 days resulted in tissue necrosis and disturbed healing. Therefore, a follow-up comparative study investigated the best treatment course for antiseptic application ranging from 7 to 21 days, followed by the oxygenating chitosan-based MACF treatment for the remainder of the 21 days. Bacterial counts, tissue assessments, and lipidomics studies showed that 14 days of application of MACF-PHMB dressings followed by 7 days of MACF dressings provides a promising treatment for managing infected non-healing diabetic skin ulcers.

1410. Improved Disinfection in the Operating Room through Hydrogen Peroxide Fogging

Abstract Background Hospital acquired infections (HAIs), including surgical site infections (SSIs), are a major contributor to morbidity. Environmental exposure is a contributing factor to HAIs. Environmental decontamination with hydrogen peroxide fogging has proven to reduce bacterial growth and bioburden in the hospital setting. We sought to 1) implement and test feasibility of an operating room (OR)-based hybrid hydrogen peroxide fogging program and 2) assess the impact of hydrogen peroxide fogging on SSIs. Methods At a large freestanding midwestern Children's Hospital with a surgical volume of over 17,000 annual surgeries, a hybrid hydrogen peroxide fogging program was implemented in a risk-stratified fashion. Baseline fogging was completed to establish a post-fogging time series for bacterial regrowth (measured by culture and bioburden) and to guide the implementation schedule. Based on time-series results, room-specific fogging parameters were established. ORs received fogging either every 2 weeks (neurosurgical, cardiac and spine ORs) or every 4 weeks (all other ORs). The fogging program was administered using a third-party vendor beginning in September 2022. The feasibility assessment was designed to identify any safety events, interruptions in care or access to the ORs due to fogging. The time series outcomes were bioburden and bacterial cultures. The primary patient outcome measure was the rate of SSIs. This is depicted in both a P chart, showing a monthly rate, and a T-chart, showing days between events. SSIs for orthopedic, spine and neurosurgeries were tracked from January 2021 to present. Results After implementation of the program there was a significant decrease in SSI rates from 3.38% to 0.68% and is represented by a center-line shift in the P chart. The days between SSIs moved in a favorable direction, increasing to 238 days, the longest since January 2021. The time series evaluation indicated return to baseline bacterial bioburden between 3 and 4 weeks post-fogging. The feasibility assessment identified no safety events, delays, interruptions or decreases in OR utilization. Surgical Site Infections (Spine, Cardiac, Neurosurgical) Since fogging began in September of 2022, we have experienced a centerline shift demonstrating a reduced rate of surgical site infections from 3.38% to 0.68%, the longest stretch between surgical site infections since January 2021. Days Between Surgical Site Infections Since fogging began in September of 2022, we have experienced the longest stretch between surgical site infections since January 2021 Conclusion Hydrogen peroxide fogging is a feasible form of disinfection and reduces SSI rates when applied in the OR of a Children’s Hospital with a moderate to large surgical volume. Disclosures Michael Bigham, MD, ForTec Medical: Advisor/Consultant

Bacterial bioburden of duodenoscope elevator mechanism in different reprocessing stages

Over the past decade, infections linked to duodenoscopes have become a significant concern, primarily due to the intricate design of the elevator mechanism. Currently, there is limited evidence regarding the bacterial contamination level of the elevator mechanism after clinical use and throughout its various reprocessing stages. This study utilized the swab culture technique to examine the bacterial contamination on the duodenoscope elevator mechanism after clinical use and after 3 reprocessing stages at a Center of tertiary hospital. Our findings revealed severe bacterial contamination after clinical usage, emphasizing that the effectiveness of manual cleaning greatly influences the subsequent high-level disinfection quality.

Biocompatible Human Placental Extracellular Matrix Derived Hydrogels.

Solubilizing extracellular matrix (ECM) materials and transforming them into hydrogels has expanded their potential applications both in vitro and in vivo. In this study, hydrogels are prepared by decellularization of human placental tissue using detergent and enzymes and by the subsequent creation of a homogenized acellular placental tissue powder (P-ECM). A perfusion-based decellularization approach is employed using detergent and enzymes. The P-ECM with and without gamma irradiation is then utilized to prepare P-ECM hydrogels. Physical and biological evaluations are conducted to assess the suitability of the P-ECM hydrogels for biocompatibility. The decellularized tissue has significantly reduced cellular content and retains the major ECM proteins. Increasing the concentration of P-ECM leads to improved mechanical properties of the P-ECM hydrogels. The biocompatibility of the P-ECM hydrogel is demonstrated through cell proliferation and viability assays. Notably, gamma-sterilized P-ECM does not support the formation of a stable hydrogel. Nonetheless, the use of HCl during the digestion process effectively decreases spore growth and bacterial bioburden. The study demonstrates that P-ECM hydrogels exhibit physical and biological attributes conducive to soft tissue reconstruction. These hydrogels establish a favorable microenvironment for cell growth and the need for investigating innovative sterilization methods.

Host CD3+ T-cells can significantly modulate phage treatment effects on bacterial bioburden in mouse models.

Wound healing is a complex system including such key players as host, microbe, and treatments. However, little is known about their dynamic interactions. Here we explored the interplay between: (1) bacterial bioburden and host immune responses, (2) bacterial bioburden and wound size, and (3) treatments and wound size, using murine models and various treatment modalities: Phosphate buffer saline (PBS or vehicle, negative control), doxycycline, and two doses of A. baumannii phage mixtures. We uncovered that the interplay between bacterial bioburden and host immune system may be bidirectional, and that there is an interaction between host CD3+ T-cells and phage dosage, which significantly impacts bacterial bioburden. Furthermore, the bacterial bioburden and wound size association is significantly modulated by the host CD3+ T-cells. When the host CD3+ T-cells (x on log10 scale) are in the appropriate range (1.35 < x < = 1.5), we observed a strong association between colony forming units (CFU) and wound size, indicating a hallmark of wound healing. On the basis of the findings and our previous work, we proposed an integrated parallel systems biology model.

Antimicrobial Activity of Silver-Containing Surgical Dressings in an In vitro Direct Inoculation Simulated Wound Fluid Model Against a Range of Gram-Positive and Gram-Negative Bacteria.

Background: Surgical site infections can lead to serious complications and present a huge economic burden. Established wound infections can be difficult to eradicate so preventative measures, including antimicrobial dressings, are advantageous. Materials and Methods: The antimicrobial activity of an ionic silver, ethylenediaminetetraacetic acid (EDTA) and benzethonium chloride-containing (ISEB) surgical cover dressing (SCD) was compared with two other silver-containing SCDs (silver sulfate and ionic silver carboxymethylcellulose [CMC]) and a non-silver-containing CMC SCD control using an in vitro model. The dressings were tested against a range of gram-positive and gram-negative bacteria found in wound environments, including antibiotic resistant strains, using a direct inoculation simulated wound fluid (SWF) model. Dressings were fully hydrated with SWF and inoculated with a final concentration of 1 × 106 colony forming units (CFU) per 10 microliter of the challenge organisms. Dressings were incubated at 35°C ± 3°C for up to seven days; total viable counts (TVCs) were performed to determine bacterial bioburden. Results: All challenge organism levels remained high for the CMC SCD control and silver sulfate SCD throughout the test period. A greater than 95% reduction in TVCs was observed by four hours for all challenge organisms for the ISEB SCD, with non-detectable levels (<70 CFU per dressing) reached within 24 hours and sustained throughout the test period. Antimicrobial activity was less rapid with ionic silver CMC SCD, with 9 of 11 challenge organisms reaching undetectable levels within 6 to 72 hours. Conclusions: A more rapid antimicrobial activity was observed for the ISEB SCD compared with other dressings tested within this in vitro model.

Influence of Staphylococcus epidermidis on Collagen Crimp Patterns of Soft Tissue Allograft

Background: Postoperative infections, commonly from Staphylococcus epidermidis, may result in anterior cruciate ligament graft failure and necessitate revision surgery. In biomechanical studies, S. epidermidis has been shown to establish biofilms on tendons and reduce graft strength. Purpose/Hypothesis: The goal of this study was to determine the effect of bacterial bioburden on the collagen structure of tendon. It was hypothesized that an increase in S. epidermidis biofilm would compromise tendon crimp, a pattern necessary for mechanical integrity, of soft tissue allografts. Study design: Controlled laboratory study. Methods: Cultures of S. epidermidis were used to inoculate tibialis anterior cadaveric tendons. Conditions assessed included 5 × 105 colony-forming units or concentrated spent media from culture (no living bacteria). Incubation times of 30 minutes, 3 hours, 6 hours, and 24 hours were utilized. Second-harmonic generation imaging allowed for visualization of collagen autofluorescence. Crimp lengths were determined using ImageJ and compared based on incubation time. Results: Incubation time positively correlated with increasing S. epidermidis bioburden. Both fine and coarse crimp patterns lengthened with increasing incubation time. Significant coarse crimp changes were observed after only 30-minute incubations (P < .029), whereas significant fine crimp lengthening occurred after 6 hours (P < .0001). No changes in crimp length were identified after incubation in media lacking living bacteria. Conclusion: The results of this study demonstrate that exposure to S. epidermidis negatively affects collagen crimp structure. Structural alterations at the collagen fiber level occur within 30 minutes of exposure to media containing S. epidermidis. Clinical Relevance: Our study highlights the need for antimicrobial precautions to prevent graft colonization and maximize graft mechanical strength.

Regulation of Bacterial Biofilm Formation by Ultrasound: Role of Autoinducer-2 and Finite-Element Analysis of Acoustic Streaming

The formation of bacterial biofilm regulated by quorum sensing (QS) is a critical factor that contributes to infections of indwelling medical devices. Autoinducer-2 (AI-2), as a signal molecule in QS, plays a crucial role in mediating bacterial signaling and regulating their biological behavior. This study investigated the impact of ultrasonic vibration at varying frequencies on biofilm formation in a mixture of Staphylococcus aureus and Escherichia coli. By exciting ultrasound at different frequencies (20, 100 and 200 kHz), a vibration with an amplitude of 100 nm was generated on the material surface located at the bottom of the petri dish containing mixed bacteria. We measured the content of AI-2 and bacteria in the mixed bacterial solution and bioburden on material surfaces at different time points during culture. In addition, the relationships among AI-2 content, bacterial concentration and distribution were assessed through finite-element analysis of acoustic streaming under ultrasonic vibration. The AI-2 gradient is influenced by the diversity of acoustic streaming patterns on the material surface and in the mixed bacterial solution caused by ultrasonic vibration at different frequencies, thereby regulating biofilm formation. The experimental results showed that the optimal inhibition effect on AI-2 and minimal bacterial adhesion degree was achieved when applying an ultrasonic frequency of 100 kHz with a power intensity of 46.1 mW/cm2 under an amplitude of 100 nm. Ultrasound can affect the QS system of bacteria, leading to alterations in their biological behavior. Different species of bacteria exhibit varying degrees of chemotaxis toward different frequencies.

Efficacy of a continuously active disinfectant wipe on the environmental bioburden in the intensive care unit: A randomized controlled study.

To evaluate the efficacy of a new continuously active disinfectant (CAD) to decrease bioburden on high-touch environmental surfaces compared to a standard disinfectant in the intensive care unit. A single-blind randomized controlled trial with 1:1 allocation. Medical intensive care unit (MICU) at an urban tertiary-care hospital. Adult patients admitted to the MICU and on contact precautions. A new CAD wipe used for daily cleaning. Samples were collected from 5 high-touch environmental surfaces before cleaning and at 1, 4, and 24 hours after cleaning. The primary outcome was the mean bioburden 24 hours after cleaning. The secondary outcome was the detection of any epidemiologically important pathogen (EIP) 24 hours after cleaning. In total, 843 environmental samples were collected from 43 unique patient rooms. At 24 hours, the mean bioburden recovered from the patient rooms cleaned with the new CAD wipe (intervention) was 52 CFU/mL, and the mean bioburden was 92 CFU/mL in the rooms cleaned the standard disinfectant (control). After log transformation for multivariable analysis, the mean difference in bioburden between the intervention and control arm was -0.59 (95% CI, -1.45 to 0.27). The odds of EIP detection were 14% lower in the rooms cleaned with the CAD wipe (OR, 0.86; 95% CI, 0.31-2.32). The bacterial bioburden and odds of detection of EIPs were not statistically different in rooms cleaned with the CAD compared to the standard disinfectant after 24 hours. Although CAD technology appears promising in vitro, larger studies may be warranted to evaluate efficacy in clinical settings.

Mathematical pharmacodynamic modeling for antimicrobial assessment of ceftazidime/colistin versus gentamicin/meropenem combinations against carbapenem-resistant Pseudomonas aeruginosa biofilm

BackgroundCarbapenem-resistant Pseudomonas aeruginosa (CRPA) represents an escalating healthcare hazard with high mortality worldwide, especially in presence of biofilm. The current study aimed to evaluate the anti-biofilm potentials of ceftazidime, colistin, gentamicin, and meropenem alone and in combinations against biofilm-forming CRPA. MethodsBiofilm killing and checkerboard assay were performed to detect the effectiveness of combined antibiotics against biofilms and planktonic cells, respectively. The bacterial bioburden retrieved from the established biofilms following treatment with combined antibiotics was utilized to construct a three-dimensional response surface plot. A sigmoidal maximum effect model was applied to determine the pharmacodynamic parameters (maximal effect, median effective concentration, and Hill factor) of each antibiotic to create a mathematical three-dimensional response surface plot.ResultsData revealed statistically significant (p < 0.05) superior anti-biofilm potential in the case of colistin followed by a lower effect in the case of gentamicin and meropenem, while ceftazidime exhibited the least anti-biofilm activity. The fractional inhibitory concentration index (FICI ≤ 0.5) indicated synergism following treatment with the combined antibiotics. An elevated anti-biofilm activity was recorded in the case of gentamicin/meropenem compared to ceftazidime/colistin. Synergistic anti-biofilm potentials were also detected via the simulated pharmacodynamic modeling, with higher anti-biofilm activity in the case of the in vitro observation compared to the simulated anti-biofilm profile.ConclusionsThe present study highlighted the synergistic potentials of the tested antibiotic combinations against P. aeruginosa biofilms and the importance of the mathematical pharmacodynamic modeling in investigating the efficacy of antibiotics in combination as an effective strategy for successful antibiotic therapy to tackle the extensively growing resistance to the currently available antibiotics.

A single-center pilot study investigating the effects of a native cross-linked extracellular matrix with polyhexamethylene biguanide to manage chronic lower extremity wounds exhibiting bacterial contamination

BACKGROUND: Elevated bacterial bioburden and biofilm formation are common causes for delayed wound healing. Biofilm is an assemblage of surface-associated microbes enclosed in a self-produced matrix. Identifying and managing biofilm is a crucial component of successful wound care protocols. PURPOSE: To determine the effects of a native cross-linked extra cellular matrix with polyhexamethylene biguanide (PHMP; PHMP antimicrobial [PCMP]), in conjunction with next-generation DNA sequencing (NGS) and targeted debridement by fluorescence imaging, on managing bacterial bioburden to support wound healing. METHODS: Over 6 weeks, fluorescence images were captured to assess bacterial contamination as were standard images with measurements. Tissue swabs were obtained and analyzed using NGS to quantify bacterial bioburden. PCMP was applied at each treatment visit. RESULTS: Baseline wound duration was 23.0 ± 6.7 weeks, and baseline size was 7.9 ± 7.1 cm2. Two out of 5 wounds healed by week 4. The mean percentage area reduction of all wounds was 59.7% by week 4 and 78.1% by week 6. All wounds were fluorescence positive on week 1 and fluorescence negative by Week 4. CONCLUSION: PCMP, as an antimicrobial barrier, combined with use of a real-time method of bacterial detection, may be beneficial in managing the wound healing environment.

Hybrid of Metapenaeus dobsoni lectin and platinum nanoparticles exert antimicrobial and immunostimulatory effects to reduce bacterial bioburden in infected Nile tilapia

A novel antibacterial immunostimulant using Platinum nanoparticles (PtNPs) and lectin from Metapenaeus dobsoni (Md-Lec) was developed. The Md-Lec and PtNPs (Pt-lec) hybrid formed through non-covalent interaction exhibits antimicrobial activity against fish specific pathogens by affecting membrane integrity and producing excess reactive oxygen species. The therapeutic efficacy of Pt-lec was demonstrated through rescuing Aeromonas hydrophila infected Nile Tilapia. Pt-lec prevents the infection spreading and reduces the bacterial bioburden in less than 12 h, and as a result of this the fish were restored to normalcy. To assess immunostimulation, we studied the expression of three different immune related genes, namely LEC, Myd88 and COX-2 in the gills, liver, spleen and kidney of fish under various experimental conditions. Our results showed that Pt-lec treatment appeared to be better when compared to lectin alone in enhancing the expression of Myd88 and COX-2, but LEC was not as expected. These results suggest that Pt-lec has the ability to protect Nile Tilapia against bacterial infection by restricting bacterial bioburden through their direct effects on the bacterial membrane and indirectly through their effects on host immune-related gene expression. This hybrid could have potential “green” application in fish farming in rescuing infected animals when compared to widely and unregulated antibiotics.

The impact of wound pH on the antibacterial properties of Medical Grade Honey when applied to bacterial isolates present in common foot and ankle wounds. An in vitro study

BackgroundDiabetic foot ulcers (DFUs) and post-surgical wound infections are amongst the most troublesome complications of diabetes and following foot and ankle surgery (FAS) respectively. Both have significant psychosocial and financial burden for both patients and the healthcare system. FAS has been reported to have higher than average post-surgical infections when compared to other orthopaedic subspecialties. Evidence also indicates that patients with diabetes and other co morbidities undergoing FAS are at a much greater risk of developing surgical site infections (SSIs). With the growing challenges of antibiotic resistance and the increasingly high numbers of resilient bacteria to said antibiotics, the need for alternative antimicrobial therapies has become critical.AimThe aim of this study was to investigate the use of medical grade honey (MGH) when altered to environments typically present in foot and ankle wounds including DFUs and post-surgical wounds (pH6-8).MethodsMGH (Activon) was altered to pH 6, 7 and 8 and experimental inoculums of Pseudomonas aeruginosa (NCTC10782), Escherichia coli, (NCTC10418), Staphylococcus aureus (NCTC10655) and Staphylococcus epidermidis (NCTC 5955) were transferred into each pH adjusted MGH and TSB solution and the positive and negative controls.ResultsMGH adjusted to various pH values had the ability to reduce bacteria cell survival in all pH variations for all bacteria tested, with the most bacterial reduction/elimination noted for Staphylococcus epidermidis. No correlations were noted among the pH environments investigated and the colony counts, for which there were small amounts of bacteria survived.ConclusionThis research would indicate that the antibacterial properties of honey remains the same regardless of the pH environment. MGH could therefore potentially be considered for use on non-infected foot and ankle wounds to reduce the bacterial bioburden, the risk of infections and ultimately to improve healing outcomes.

Diagnostic Accuracy of a Fluorescence Imaging Device in Diabetic Wounds: A Pilot Study Using a Tissue Culture System

Introduction. DFUs are challenging chronic wounds that are vulnerable to infections. A fluorescence imaging device was developed to detect bacterial presence in wounds. This device utilizes the principle that when illuminated by violet light, some bacteria emit red fluorescence and others, such as Pseudomonas aeruginosa, emit cyan fluorescence. Several studies have reported the accuracy of this device. However, to the best of the authors’ knowledge, no studies have examined the correlation between bacterial presence and tissue biopsy culture results in diabetic wounds. Objective. This study aimed to investigate the diagnostic accuracy of a fluorescence imaging device using a tissue culture system. Materials and Methods. Thirty-five patients (48 wounds) were included. Wounds were sampled using tissue culture methods and photographed using the fluorescence imaging device. Culture outcomes were categorized into non-Pseudomonas bacterial, Pseudomonas bacterial, both bacterial, and no-growth groups. Image outcomes were categorized into red, cyan, both colors, and negative groups. Results. For detecting the presence of bacteria, the fluorescence imaging device showed a sensitivity, specificity, PPV, and NPV of 64.1%, 55.6%, 86.2%, and 26.3%, respectively, with an accuracy of 62.5%. For P aeruginosa, the device showed a sensitivity, specificity, PPV, and NPV of 66.7%, 87.2%, 54.6%, and 91.9%, respectively, with an accuracy of 83.3%. For non-Pseudomonas bacteria, the device showed a sensitivity, specificity, PPV, and NPV of 43.8%, 62.5%, 70.0%, and 35.7%, respectively, with an accuracy of 50.0%. Conclusion. The fluorescence imaging device can help to detect the bacterial bioburden; however, its accuracy may be lower than that reported in previous studies of diabetic wounds.

1187. Analysis of the Clonal Recovery Pattern of Enterococcus faecium to Evaluate the Efficacy of Pulsed Xenon Ultraviolet Light (PX-UV) in Bioburden Reduction

Abstract Background Enterococcus faecium (E. faecium) is a common hospital-associated infection (HAI) that can lead to increased costs, morbidity, and mortality. Pulsed Xenon Ultraviolet light (PX-UV) has been shown to reduce bacterial bioburden levels on surfaces. This study aims to assess the effect of the addition of PX-UV to terminal cleaning on the clonal recovery of E. faecium sequence types (STs) using Whole Genome Sequencing (WGS) on patient isolates. Methods During 2017 to 2020 a prospective, randomized, double-blinded, sham-controlled, interventional, crossover trial in 2 separate Detroit hospitals (H1 and H2) compared HAI counts after the addition of either PX-UV or a non-UV sham device to terminal cleaning methods. The trial consisted of a total of 16 units randomized to have either the treatment of PX-UV (Group Q) or the sham control device with no UV (Group W) for 12 months. A washout period (Group R) of 6 months followed and the trial concluded with a 12-month crossover of treatments. A total of 60 E. faecium samples were collected, then WGS was performed by the Illumina Nextseq 550 instrument. de novo assembly was preformed using the SPAdes program. Whole Genome Multilocus Sequence Type (wgMLST) analysis was performed by BioNumerics (v7.6) to construct minimum spanning tree (MST). Results A total of 7 STs were obtained across the 2 hospitals (H1 and H2). ST117, ST17, and ST80 all had more than 10 total recovered isolates, ST117 being the most frequent with 24 isolates. Less than 3 isolates were recovered for all other STs. For all STs, Group Q (PX-UV) had 14, Group R (washout period) had 22, and Group W (non-UV sham) had 24. ST18 was only found in Group Q. ST412, ST584, and ST736 were not found in Group W. The data shows that the intervention PX-UV group had a reduction of clonal recovery by 10 STs as compared to the sham UV group. Table 1:Total number of each sequence type (ST) in H1 and H2 Conclusion The overall reductions in the number of isolates in the real UV units was driven by reductions in the ST117 a predominant strain in a hospital environment reported previously in Detroit and ST80. There were negligible differences in recovery of other ST between the groups. The reduction in clonal recovery of E. faecium isolates in Group Q as compared to Group R might be related to use of PX-UV following terminal room cleaning. Disclosures Piyali Chatterjee, PhD, AHRQ Grant # 1R03HS027667-01: Grant/Research Support|AHRQ Grant # 1R03HS027667-01: Central Texas Veterans Health Care System Keith S. Kaye, MD, MPH, Allecra: Advisor/Consultant|GlaxoSmithKline plc.: Receiving symposia honoraria|GlaxoSmithKline plc.: GlaxoSmithKline plc.-sponsored study 212502|Merck: Advisor/Consultant|qpex: Advisor/Consultant|Shionogi: Grant/Research Support|Spero: Advisor/Consultant Chetan Jinadatha, MD, MPH, AHRQ R01 Grant-5R01HS025598: Grant/Research Support|EOS Surfaces: Copper Coupons and materials for testing.