Bacterial Bioburden Research Articles

The influence of a biofilm-dispersing wound gel on the wound healing process.

Topical antimicrobials that reduce the bacterial bioburden within a chronically‐infected wound may have helpful or harmful effects on the healing process. We used murine models of full‐thickness skin wounds to determine the effects of the novel biofilm‐dispersing wound gel (BDWG) and its gel base on the healing of uninfected wounds. The rate of wound closure over 19 days was comparable among the BDWG‐treated (BT) wounds and the controls. Compared with the controls, histology of the BT wounds showed formation of a stable blood clot at day 1, more neovascularisation and reepithelialisation at day 3, and more organised healing at day 7. Fluorescence‐activated cell sorting analysis showed a lower percentage of neutrophils in wounded tissues of the BT group at days 1 and 3, and significantly more M2 macrophages at day 3. Levels of proinflammatory cytokines and chemokines were increased over the uninjured baseline within the wounds of all treatment groups but the levels were significantly lower in the BT group at day 1, modulating the inflammatory response. Our results suggest that BDWG does not interfere with the wound healing process and may enhance it by lowering inflammation and allowing transition to the proliferative stage of wound healing by day 3.

Effect of ultraviolet-C light on the environmental bacterial bioburden in various veterinary facilities.

To determine the effect of a mobile UV-C disinfection device on the environmental bacterial bioburden in veterinary facilities. 40 swab samples of surfaces from the operating theaters of 3 veterinary hospitals and 1 necropsy laboratory. Various surfaces were swabbed, and collected material was eluted from the swabs in PBSS. Then, an aliquot of the sample fluid was processed with a bacteria-specific rapid metabolic assay to quantify bacterial bioburden. Each site was then treated with UV-C light with an automated disinfection device for approximately 45 minutes. The same surfaces were swabbed following UV-C treatment, and bioburden was quantified. The bioburden at additional time points, including after a second UV-C treatment, was determined for the small animal operating theater. All surfaces at all sites had a persistent viable bacterial population following manual cleaning. Disinfection with UV-C achieved a mean bioburden reduction of 94% (SD, 5.2%; range, 91% to 95%) for all surfaces, compared with manual disinfection alone. Repeated UV-C treatment of the small animal operating theater reduced mean bioburden by 99% (SD, 0.8%), including no detectable bacteria on 4 of 10 surfaces. Disinfection with UV-C light may be a beneficial adjunct method for terminal disinfection of veterinary operating theaters to reduce environmental bioburden. (Am J Vet Res 2021;82:582-588).

Recombinant Ax21 protein is a promising subunit vaccine candidate against Stenotrophomonas maltophilia in a murine infection model

Stenotrophomonas maltophilia is an emerging pathogen that can cause several disease manifestations such as bacteremia, meningitis, respiratory tract infections and others. More seriously, this pathogen has a highly evolving antibiotic resistance profile. Antibiotic misuse is further aggravating the situation by inducing the development of multi- and even pan-resistance. Thus, employing diverse strategies to overcome this increasing antibiotic resistance is of paramount importance. In general, vaccination is one of these strategies that prevents the onset of infection, provides long term protection against infection, and most importantly diminishes the antibiotic consumption, thus, resulting in controlling resistance. Unfortunately, vaccine research concerning S. maltophilia is very scarce in the literature. Ax21 protein is an outer membrane protein implicated in several virulence mechanisms of S. maltophilia such as quorum sensing, biofilm formation, and antibiotic resistance. Our computational analysis of Ax21 revealed its potential immunogenicity. In the current study, Ax21 protein of S. maltophilia was cloned and heterologously expressed in Escherichia coli. Mice were immunized with the purified recombinant antigen using Bacillus Calmette-Guérin(BCG) and incomplete Freund’s adjuvant (IFA) as immune-adjuvants. Enzyme-linked immunosorbent assay (ELISA) revealed significant antigen-specific IgG1, IgG2a and total IgG levels in immunized mice which reflected successful immune stimulation. Immunized mice that were challenged with S. maltophilia showed a substantialreduction in bacterial bioburden in lungs, liver, kidneys, and heart. In addition, liver histological examination demonstrated a remarkable decrease in pathological signs such as necrosis, vacuolation, bile duct fibrosis and necrosis, infiltration of inflammatory cells, and hemorrhage. Whole cell ELISA and opsonophagocytic assay confirmed the ability of serum antibodies from immunized mice to bind and facilitate phagocytosis of S. maltophilia, respectively. To our knowledge, this is the first report to demonstrate the vaccine protective efficacy of Ax21 outer membrane protein against S. maltophilia infection.

Expeditionary Plastic Surgery: Reconstruction Pearls for the Non-plastic Surgeon Managing Injured Host Nationals

This review focuses on techniques for reconstructing soft tissue injuries in host nationals that can be performed by non-plastic surgeons in a deployed environment. Advances in wound care technology and techniques have created opportunities to bring world-class care to injured host nationals. Negative pressure wound therapy with instillation can reduce bacterial bioburden, decrease the number of operative debridements, and decrease time to wound closure, saving scarce resources in a deployed setting. Perforator-based pedicle flaps can be utilized to cover large soft tissue defects with minimal donor site morbidity and excellent flap survival. Targeted muscle reinnervation can be performed at the time of an amputation to decrease chronic neuropathic pain. Techniques from simple to complex can be learned and successfully performed by the general, trauma, and orthopedic surgeons in austere locations in order to effectively leverage limited resources for the best outcomes for host nationals.

Acceleration of cutaneous wound healing by Lucilia sericata maggots in diabetic Wistar rats.

The study was aimed to evaluate the effectiveness of maggot therapy in healing of cutaneous infected wound in streptozotocin (STZ) induced diabetic Wistar rat. For live maggots, the sterilized eggs of Lucilia sericata were obtained from colonies established in laboratory. Diabetes model was established in 48 male Wister rat by intra-peritoneal injection of STZ at the dose of 60 mg/kg body-weight. Cutaneous wounds exposed with mixed colonies of bacteria like Staphylococcus aureus, E. coli and Pseudomonas aeruginosa were prepared in all rat. The animals equally divided in 4 groups with 12 rats each being presented as treatment group of control, antibiotic, maggot and maggot with antibiotic in combination. All treatments were done once and hold for 24 hours. Wound kinetics and bacterial bio burden were measured at weekly interval to till complete healing. Significant reduction in wound area with maximum contraction was found (>95%) in maggot treated group when compared to antibiotic treated (79%) and control (72%). In maggot as well as maggot and antibiotic in combination group showed early elimination of bacterial bio-burden 7.88±0.03log CFU/ml to 1.12±0.65log CFU/ml and 7.86±0.04) log CFU/ml to 1.54±0.52log CFU/ml respectively in three weeks of time. Early healing indication was also experienced on histomorphological examination of wounded tissue of maggot treated groups by early and better epithelialization, collagenation and neovascularization with complete healing of wound in three weeks in comparison to antibiotic and control respectively. However, the present study did not show any difference in healing of wound with use of maggot alone or in antibiotic combination. Live maggot of Lucilia sericata effectively lower bacterial bioburden and and accelerate healing of infected cutaneous wound in diabetic conditions.

Antimicrobial efficacy and durability of copper formulations over one year of hospital use

To evaluate 3 formulations of copper (Cu)-based self-sanitizing surfaces for antimicrobial efficacy and durability over 1 year in inpatient clinical areas and laboratories. Randomized control trial. We assessed 3 copper formulations: (1) solid alloy 80% Cu-20% Ni (integral copper), (2) spray-on 80% Cu-20% Ni (spray-on) and (3) 16% composite copper-impregnated surface (CIS). In total, 480 coupons (1 cm2) of the 3 products and control surgical grade (AISI 316) stainless steel were inserted into gaskets and affixed to clinical carts used in patient care areas (including emergency and maternity units) and on microbiology laboratory bench work spaces (n = 240). The microbial burden and assessment of resistance to wear, corrosion, and material compatibility were determined every 3 months. Participants included 3 tertiary-care Canadian adult hospital and 1 pediatric-maternity hospital. Copper formulations used on inpatient units statistically significantly reduced bacterial bioburden compared to stainless steel at months 3 and 6. Only the integral copper product had significantly less bacteria than stainless steel at month 12. No statistically significant differences were detected in microbial burden between copper formulations and stainless-steel coupons on microbiology laboratory benches where bacterial counts were low overall. All mass changes and corrosion rates of the formulations were acceptable by engineering standards. Copper surfaces vary in their antimicrobial efficacy after 1 year of hospital use. Frequency of cleaning and disinfection influence the impact of copper; the greatest reduction in microbial bioburden occurred in clinical areas compared to the microbiology laboratory where cleaning and disinfection were performed multiple times daily.

Brass Alloys: Copper-Bottomed Solutions against Hospital-Acquired Infections?

Copper has been used for its antimicrobial properties since Antiquity. Nowadays, touch surfaces made of copper-based alloys such as brasses are used in healthcare settings in an attempt to reduce the bioburden and limit environmental transmission of nosocomial pathogens. After a brief history of brass uses, the various mechanisms that are thought to be at the basis of brass antimicrobial action will be described. Evidence shows that direct contact with the surface as well as cupric and cuprous ions arising from brass surfaces are instrumental in the antimicrobial effectiveness. These copper ions can lead to oxidative stress, membrane alterations, protein malfunctions, and/or DNA damages. Laboratory studies back up a broad spectrum of activity of brass surfaces on bacteria with the possible exception of bacteria in their sporulated form. Various parameters influencing the antimicrobial activity such as relative humidity, temperature, wet/dry inoculation or wear have been identified, making it mandatory to standardize antibacterial testing. Field trials using brass and copper surfaces consistently report reductions in the bacterial bioburden but, evidence is still sparse as to a significant impact on hospital acquired infections. Further work is also needed to assess the long-term effects of chemical/physical wear on their antimicrobial effectiveness.

Environmental Contamination of Contact Precaution and Non-Contact Precaution Patient Rooms in Six Acute Care Facilities.

Environmental contamination is an important source of hospital multidrug-resistant organism (MDRO) transmission. Factors such as patient MDRO contact precautions (CP) status, patient proximity to surfaces, and unit type likely influence MDRO contamination and bacterial bioburden levels on patient room surfaces. Identifying factors associated with environmental contamination in patient rooms and on shared unit surfaces could help identify important environmental MDRO transmission routes. Surfaces were sampled from MDRO CP and non-CP rooms, nursing stations, and mobile equipment in acute care, intensive care, and transplant units within 6 acute care hospitals using a convenience sampling approach blinded to cleaning events. Precaution rooms had patients with clinical or surveillance tests positive for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, carbapenem-resistant Enterobacteriaceae or Acinetobacter within the previous 6 months, or Clostridioides difficile toxin within the past 30 days. Rooms not meeting this definition were considered non-CP rooms. Samples were cultured for the above MDROs and total bioburden. Overall, an estimated 13% of rooms were contaminated with at least 1 MDRO. MDROs were detected more frequently in CP rooms (32% of 209 room-sample events) than non-CP rooms (12% of 234 room-sample events). Surface bioburden did not differ significantly between CP and non-CP rooms or MDRO-positive and MDRO-negative rooms. CP room surfaces are contaminated more frequently than non-CP room surfaces; however, contamination of non-CP room surfaces is not uncommon and may be an important reservoir for ongoing MDRO transmission. MDRO contamination of non-CP rooms may indicate asymptomatic patient MDRO carriage, inadequate terminal cleaning, or cross-contamination of room surfaces via healthcare personnel hands.

Biosynthesized silver nanoparticles loaded in gelatine hydrogel for a natural antibacterial and anti-biofilm wound dressing

Antibiotic-resistance and bacterial bioburden are the threats to wound healing. Nanoparticles are a revolutionary advancement in nanomedicine owing to their antibacterial properties, to be used as a promising alternative to antibiotics. A wound dressing with antibacterial and anti-biofilm effects may be a plausible strategy in curbing wound exacerbation caused by bacterial infection. Silver nanoparticles (AgNPs) are known for their excellent antibacterial activity. In present study, biosynthesized AgNPs using spent mushroom substrate (SMS) as reducing agent while chitosan as stabilizing agent were successfully produced. The nanoparticles exhibited considerable antibacterial and anti-biofilm activities with higher sensitivity towards Gram-negative bacteria. These AgNPs were later incorporated into genipin-crosslinked gelatine hydrogels as a wound dressing. The hydrogels were characterized for their physical, rheological and swelling properties, besides in vitro release of AgNPs. The formulated hydrogels demonstrated an adequate release of the AgNPs with acceptable physical, rheological and swelling properties, suitable as a vehicle for wound drug delivery. The antibacterial and anti-biofilm of the hydrogels against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli were effective in inhibiting the growth of the selected bacteria with minimum inhibitory concentration (MIC) of 63 μg/mL. In summary, genipin-crosslinked gelatine hydrogels loaded with the AgNPs are a promising anti-microbial wound dressing, a potential strategy for combating biofilm of wound infections and accelerating healing.

Non-surgical treatment for pressure ulcer

Pressure, friction, shear force, and micromoisture can cause pressure ulcer. With the increase of the elderly population in Korea, the number of decubitus pressure ulcer patients is increasing due to worsening medical conditions by aging. In the case of quadriplegic and hemiplegic patients, there is considerable interest in the prevention and self-treatment of pressure ulcer following daily life recovery through rehabilitation. It is important to recognize that pressure ulcer can sometimes be avoided and can sometimes occur inevitably, and that preventive measures should be put in place. For the improvement of pressure ulcer, the patient’s systemic condition and the understanding of indications for local treatment should be improved. Recently, guidelines for dressing formulations related to exudate absorption capacity were introduced. For the successful treatment of pressure ulcer, adequate support of nutrition, control of stiffness, prevention of bacterial bioburden, removal of dead tissue (debridement), moisturizing of the skin, and selection of appropriate dressing materials should be applied comprehensively for individual patients.

Direct detection of microorganisms in sonicated orthopedic devices after in vitro biofilm production and different processing conditions.

The gold standard for microbial detection in prosthetic joint infections is the multiple culture of the peri-prosthetic tissue. The fluid cultures after sonication can improve the recovery of the microorganisms. The aim of this study was to evaluate the sonication technique with a plastic bag and the effect of refrigeration on microorganism detection with conventional culturing, MALDI-TOF MS and qPCR assay on an orthopedic screw model. We produced biofilms of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans on orthopedic screws, which were stored under different conditions and temperatures before sonication. After sonication, the mass spectrometry by MALDI-TOF, qPCR and culture protocols was performed using the sonicated fluid, for detecting the microorganisms involved in the biofilm. The bacterial bioburden decreased by approximately one log after the refrigeration period, in the screws containing P. aeruginosa and S. aureus biofilms. All the microorganisms involved in the screw biofilms were detected with MALDI-TOF and qPCR. Significant reductions in CFU counts occurred only in groups stored in the plastic bag, indicating that changes in temperature and humidity may favor cell death. However, this variation is not important for this model as it did not affect the detection owing to the high counts obtained. Microbial identification by MALDI-TOF in sonicated fluid is feasible. With qPCR, there were no differences between the detection in the screws processed immediately or after refrigeration. It is necessary to consider whether or not the refrigeration period would affect microbial recovery in an explanted prosthesis.

Management of Acute and Traumatic Wounds With Negative-Pressure Wound Therapy With Instillation and Dwell Time.

A promising and useful development of negative-pressure wound therapy (NPWT) is the addition of instillation and dwell time of topical wound solutions (NPWTi-d). Uses of NPWTi-d include acute and traumatic wounds, whereby wound closure may be facilitated via wound cleansing and promotion of granulation tissue formation. This systematic review summarizes publications on NPWTi-d in the treatment of acute and traumatic wounds. A systematic review was performed analyzing articles from major clinical databases. Only clinical studies ≥10 patients reporting on the application of NPWTi-d in acute and traumatic wounds were included. One hundred ninety-two articles were retrieved, of which 10 articles met inclusion criteria. Of those, 2 were lesser-quality randomized controlled trials, comparative studies or prospective cohorts, 2 were retrospective studies, and 6 retrospective cohort studies. In total, included publications reported 109 patients with acute and traumatic wounds treated with NPWTi-d. Data from these studies indicated the potential for reduction in bacterial bioburden through wound cleansing and promotion of granulation tissue formation, thereby facilitating wound closure, reduced length of therapy and hospital time. However, for most publications, different wound causes and subsequently no isolated results for acute and traumatic wounds were reported. NPWTi-d has promise to be effective in facilitating wound closure and reducing the time for wound closure. The present systematic review demonstrates a relatively low level of evidence available to objectively support this effect. To underline these positive results, large prospective, randomized controlled trials are necessary to manifest the role of NPWTi-d in the daily clinical routine for this wound category.

Selective delivery of silver nanoparticles for improved treatment of biofilm skin infection using bacteria-responsive microparticles loaded into dissolving microneedles

The treatment of infected chronic wounds has been hampered by development of bacterial biofilms and the low penetration of antibacterial compounds delivered by conventional dosage forms. Numerous bacterial biofilm formers have shown resistance to synthetic antibacterial agents. In this study, we explore the potential of silver nanoparticles (NPs) synthesized using green tea extract as antibiofilm agents against Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) biofilms. Due to the toxicity of silver NPs, for the first time, silver NPs were incorporated into bacteria-responsive microparticles (MPs) prepared from poly (Ɛ-caprolactone) decorated with chitosan. The in vitro release of silver NPs from MPs increased up to 9-times in the presence of SA and PA, showing the selectivity of this approach. Incorporation of the MPs into dissolving microneedles (DMNs) could enhance the dermatokinetic profiles of silver NPs compared to DMNs containing silver NPs without MP formulations and conventional cream formulations. Furthermore, 100% of bacterial bioburdens were eradicated on ex vivo biofilm model in rat skin following 60 h of the administration of this system. The findings revealed here confirmed the feasibility of the loading of silver NPs into responsive MPs for improved antibiofilm activities when delivered using DMNs. Following on from these promising results, toxicity and in vivo pharmacodynamic studies should now be carried out in an appropriate model.

A Genomic Approach to Investigating Ocular Surface Microorganisms: Monitoring Core Microbiota on Eyelid Margin with a Dot hybridization Assay.

A sound ocular surface microbiota has been recognized as a part of ocular surface health following a growing body of evidence from next-generation sequencing technique and metagenomic analysis. However, even from the perspective of contemporary precision medicine, it is difficult to directly apply these new technologies to clinical practice. Therefore, we proposed a model based on dot hybridization assay (DHA) to bridge conventional culture with a metagenomic approach in investigating and monitoring ocular surface microbiota. Endophthalmitis, mostly caused by bacterial infection, is the most severe complication of many intraocular surgeries, such as cataract surgery. Hazardous microorganisms hiding and proliferating in the ocular surface microbiota not only increase the risk of endophthalmitis but also jeopardize the effectiveness of the preoperative aseptic procedure and postoperative topical antibiotics. The DHA model enables the simultaneous assessment of bacterial bioburden, detection of target pathogens and microorganisms, and surveillance of methicillin/oxacillin resistance gene mecA in the ocular surface microbiota. This assay revealed heavier bacterial bioburden in men, compatible with a higher risk of endophthalmitis in male patients who underwent cataract surgery. No occurrence of endophthalmitis for these patients was compatible with non-hazardous microorganisms identified by specific dots for target pathogens. Moreover, the mecA dot detected oxacillin-resistant strains, of which culture failed to isolate. Therefore, the DHA model could provide an alternative genomic approach to investigate and monitor ocular surface microorganisms in clinical practice nowadays.

Proposed Mechanism of Action of Topically Applied Autologous Blood Clot Tissue.

Chronic wounds, especially in patients with diabetes, often represent clinical challenges. Recently, the use of a topically applied blood clot has garnered significant interest. This stromal matrix contains viable cells that are autologous, biocompatible, biological, and consistent with a metabolically active scaffold. It has been shown to be safe, effective, and cost-efficient. However, the mechanism of action of this modality remains elusive. We sought to identify a potential mechanism of action of an autologous blood clot. Review of clinical and scientific literature hypothesizes on how autologous blood clots may stimulate healing and facilitate the movement of critical substrates while lowering bioburden and fostering angiogenesis. Blood serves as a carrier for many components: red blood cells, white blood cells, platelets, proteins, clotting factors, minerals, electrolytes, and dissolved gasses. In response to tissue injury, the hemostatic mechanism uses a host of vascular and extravascular responses initiating primary, secondary, and tertiary hemostasis. The scaffold created by the autologous blood clot tissue provides a medium in which the body can transform the wound from a nonhealing chronic condition into a healing acute condition. The autologous blood clot tissue also creates a protective setting for the body to use its own mechanisms to promote wound healing in an organized manner. This transient scaffold recruits surrounding fibroblasts and promotes cell ingrowth to foster granulation tissue remodeling. Cells in this matrix sense not only soluble factors but also their physical environments. This well-orchestrated mechanism includes signals from soluble molecules, from the substrate/matrix to which the cell is adherent, from the mechanical or physical forces acting on it, and from contact with other cells. Topically applied autologous blood clot tissue can lower bacterial bioburden while stimulating angiogenesis and fostering the movement of keratinocytes and fibroblasts. Topically applied autologous blood clot tissue is a formidable cellular and tissue-based therapy that has been shown to be safe and effective. Although the central component of this therapy is blood, the autologous clot tissue creates a scaffold that performs as a biological delivery system that functions to control the release of growth factors and cytokines over several days.

Alcohol Hand Rub Significantly Reduces Overall Bacterial Bioburden on Stethoscopes in a Real-World Clinical Setting

Background: Stethoscopes are a known vector for microbial transmission; however, common strategies used to clean stethoscopes pose certain barriers that prevent routine cleaning after every use. We aimed to determine whether using readily available alcohol-based hand rub (ABHR) would effectively reduce bacterial bioburden on stethoscopes in a real-world setting. Methods: We performed a randomized study on inpatient wards of an academic medical center to assess the impact of using ABHR (AlcareExtra; ethyl alcohol, 80%) on the bacterial bioburden of stethoscopes. Stethoscopes were obtained from healthcare providers after routine use during an inpatient examination and were randomized to control (no intervention) or ABHR disinfection (2 pumps applied to tubing and bell or diaphragm by study personnel, then allowed to dry). Cultures of the tubing and bell or diaphragm were obtained with premoistened cellulose sponges. Sponges were combined with 1% Tween20-PBS and mixed in the Seward Stomacher. The homogenate was centrifuged and all but ~5 mL of the supernatant was discarded. Samples were plated on sheep’s blood agar and selective media for clinically important pathogens (CIPs) including S. aureus, Enterococcus spp, and gram-negative bacteria (GNB). CFU count was determined by counting the number of colonies on each plate and using dilution calculations to calculate the CFU of the original ~5 mL homogenate. Results: In total, 80 stethoscopes (40 disinfection, 40 control) were sampled from 46 physicians (MDs) and MD students (57.5%), 13 advanced practice providers (16.3%), and 21 nurses (RNs) and RN students (26.3%). The median CFU count was ~30-fold lower in the disinfection arm compared to control (106 [IQR, 50–381] vs 3,320 [986–4,834]; P < .0001). The effect was consistent across provider type, frequency of recent usual stethoscope cleaning, age, and status of pet ownership (Fig. 1). Overall, 26 of 80 (33%) of stethoscopes harbored CIP. The presence of CIP was lower but not significantly different for stethoscopes that underwent disinfection versus controls: S. aureus (25% vs 32.5%), Enterococcus (2.5% vs 10%), and GNB (2.5% vs 5%). Conclusions: Stethoscopes may serve as vectors for clean hands to become recontaminated immediately prior to performing patient care activities. Using ABHR to clean stethoscopes after every use is a practical and effective strategy to reduce overall bacterial contamination that can be easily incorporated into clinical workflow. Larger studies are needed to determine the efficacy of ABHR at removing CIP from stethoscopes as stethoscopes in both arms were frequently contaminated with CIP. Prior cleaning of stethoscopes on the study day did not seem to impact contamination rates, suggesting the impact of alcohol foam disinfection is short-lived and may need to be repeated frequently (ie, after each use).Funding: NoneDisclosures: NoneDisclosures: NoneFunding: None

Application of a Continuously Active Antimicrobial Surface Coating in Two Professional Sports Training Facilities

Background: The role of surface contamination in infections is of interest in healthcare as well as other industries, especially where infections incur high cost. One such industry is professional sports, where infections pose significant risks to players and the organizations that employ them. Sports training facilities experience highly variable occupancy rates due to differing seasonal activities, presenting a measurement challenge because the relationship between occupancy and surface contamination is not well described. In a recent publication, a continuously active antimicrobial (CAA) surface coating demonstrated a reduction in bacterial bioburden in ICUs alongside a reduction in healthcare-associated infections (HAIs). Objective: We investigated the impact of a CAA surface coating on bioburden in 2 professional sports training facilities, despite changes in occupancy. Methods: A CAA surface coating was applied using an electrostatic sprayer to all surfaces in both facilities during a period of high-occupancy at facility A and during low occupancy at facility B. Surface cultures were taken using 3M Sponge-Sticks from lockers, gym equipment, and physiotherapy surfaces before treatment, 4–13 weeks after treatment at facility A and 4–23 weeks after treatment at facility B. Total aerobic bacteria counts were obtained by plating on tryptic soy agar, and geometric means of aerobic plate counts (APCs) were used to compare bioburden before and after treatment at both facilities and for an out-of-efficacy period at facility B (17–23 weeks). Occupancy rates were monitored as person days per week (pd/w) over the course of the study. Results: APC counts at facility A decreased 61% (585 CFU/100 cm2 to 226 CFU/100 cm2) from baseline to posttreatment, and occupancy remained constant (165 pd/w to 171 pd/w). At facility B, there was no significant change in APC (76 CFU/100 cm2 to 80 CFU/100 cm2), although occupancy increased >13,000% during the treatment period (3 pd/w to 386 pd/w). During the out-of-efficacy period at facility B, total bacteria increased 170% (217 CFU/100 cm2) compared to the treatment period, and the occupancy remained relatively constant (344 pd/w). Conclusions: Levels of bioburden were significantly influenced by the application of the CAA surface coating, especially considering the variation in occupancy in both facilities before, during, and after the efficacy period. Facility A saw a significant reduction in bioburden during the treatment period (P < .0001), and a significant increase was observed at facility B during the out-of-efficacy period (P < .0001) despite constant occupancy rates, demonstrating the ability of the surface coating to reduce bioburden levels despite large changes in occupancy.Funding: Allied BioScience, Inc, provided Funding: for this study.Disclosures: Gavri Grossman, Valerie Beck, and Daniel S Watson report salary from Allied BioScience.

Contamination of Healthcare Worker Personal Protective Equipment with MRSA Outside the Intensive Care Unit Setting

Background: Estimates of contamination of healthcare personnel (HCP) gloves and gowns with methicillin-resistant Staphylococcus aureus (MRSA) following interactions with colonized or infected patients range from 17% to 20%. Most studies were conducted in the intensive care unit (ICU) setting where patients had a recent positive clinical culture. The aim of this study was to determine the rate of MRSA transmission to HCP gloves and gown in non-ICU acute-care hospital units and to identify associated risk factors. Methods: Patients on contact precautions with history of MRSA colonization or infection admitted to non-ICU settings were randomly selected from electronic health records. We observed patient care activities and cultured the gloves and gowns of 10 HCP interactions per patient prior to doffing. Cultures from patients’ anterior nares, chest, antecubital fossa and perianal area were collected to quantify bacterial bioburden. Bacterial counts were log transformed. Results: We observed 55 patients (Fig. 1), and 517 HCP–patient interactions. Of the HCP–patient interactions, 16 (3.1%) led to MRSA contamination of HCP gloves, 18 (3.5%) led to contamination of HCP gown, and 28 (5.4%) led to contamination of either gloves or gown. In addition, 5 (12.8%) patients had a positive clinical or surveillance culture for MRSA in the prior 7 days. Nurses, physicians and technicians were grouped in “direct patient care”, and rest of the HCPs were included in “no direct care group.” Of 404 interactions, 26 (6.4%) of providers in the “direct patient care” group showed transmission of MRSA to gloves or gown in comparison to 2 of 113 (1.8%) interactions involving providers in the “no direct patient care” group (P = .05) (Fig. 2). The median MRSA bioburden was 0 log 10CFU/mL in the nares (range, 0–3.6), perianal region (range, 0–3.5), the arm skin (range, 0-0.3), and the chest skin (range, 0–6.2). Detectable bioburden on patients was negatively correlated with the time since placed on contact precautions (rs= −0.06; P < .001). Of 97 observations with detectable bacterial bioburden at any site, 9 (9.3%) resulted in transmission of MRSA to HCP in comparison to 11 (3.6%) of 310 observations with no detectable bioburden at all sites (P = .03). Conclusions: Transmission of MRSA to gloves or gowns of HCP caring for patients on contact precautions for MRSA in non-ICU settings was lower than in the ICU setting. More evidence is needed to help guide the optimal use of contact precautions for the right patient, in the right setting, for the right type of encounter.Funding: NoneDisclosures: None

Analysis: Overcoming Human Factors Challenges of Endoscope Culturing with Turbulent Fluid Flow.

Analysis: Overcoming Human Factors Challenges of Endoscope Culturing with Turbulent Fluid Flow.

Simultaneous inhibition of MarR by salicylate and efflux pumps by curcumin sensitizes colistin resistant clinical isolates of Enterobacteriaceae

Carbapenem resistant Enterobacteriaceae (CRE) infection has been widely treated with last resort antibiotics like colistin. Resistance to colistin has further jeopardized the situation. We have previously reported a combination of MarR inhibitor – salicylate (Sal) and an efflux pump inhibitor (BC1) that successfully restored colistin (Col) sensitivity in multidrug and colistin resistant clinical isolate of E. coli U3790. Since synthetic compounds usually fail during drug development initiatives, we attempted to replace synthetic efflux pump inhibitor (BC1) with plant metabolite as efflux pump inhibitor to restore colistin sensitivity in CRE. Screening 13 plant metabolites, we narrowed on curcumin (CUR) to effectively inhibit efflux in both colistin resistant E. coli U3790 and K. pneumoniae BC936. Combination of Col + CUR showed a remarkable reversal in colistin MIC by 128 fold and 32 fold in E. coli U3790 and K. pneumoniae BC936 respectively. Studies with knock out mutant strains of AcrAB-TolC pump components show that curcumin's efflux inhibition is partly mediated by acrB. Thus, curcumin reduced colistin MIC well below the CLSI breakpoint (<2 μg/ml). Curcumin also exhibited synergy with colistin against most of the clinical isolates of Enterobacteriaceae tested. Efficiency of Col + Sal + CUR was evident in time kill curve analysis, which displayed a 6 log and a 4 log decline in CFU/ml by 24 h in U3790 and BC936 strains respectively. In vivo intramuscular fish infection studies showed that the triad combination reduced the bacterial bioburden of E. coli U3790 by 2.6 log and that of K. pneumoniae BC936 by 1.6 log. Hence, our study shows the efficacy of inhibiting MarR by salicylate and inhibiting efflux pump with curcumin restores colistin sensitivity in colistin resistant Enterobacteriaceae in vitro and in vivo.