HOCl-producing electrochemical bandage is active in murine polymicrobial wound infection

Derek Fleming,¹ Ibrahim Bozyel,² Christina A. Koscianski,¹ Dilara Ozdemir,² Melissa J. Karau,¹ Luz Cuello,¹ Md Monzurul Islam Anoy,² Suzanne Gelston,² Audrey N. Schuetz,¹ Kerryl E. Greenwood-Quaintance,¹ Jayawant N. Mandrekar,³ Haluk Beyenal,² Robin Patel_^1,4 AUTHOR AFFILIATIONS See affiliation list on p. 13.

ABSTRACT Wound infections, exacerbated by the prevalence of antibiotic-resistant bacterial pathogens, necessitate innovative antimicrobial approaches. Polymicrobial infections, often involving Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), present challenges due to biofilm formation and antibiotic resistance. Hypochlorous acid (HOCl), a potent antimicrobial agent, holds promise as an alternative therapy. An electrochemical bandage (e-bandage) that generates HOCl in situ via precise polarization controlled by a miniaturized potentiostat was evaluated for the treatment of murine wound biofilm infections containing both P. aeruginosa with “difficult-to-treat” resistance and MRSA. Previously, HOCl-producing e-bandage was shown to reduce murine wound biofilms containing P. aeruginosa alone. Here, in 5-mm excisional skin wounds containing 48-h biofilms comprising MRSA and P. aeruginosa combined, polarized e-bandage treatment reduced MRSA by 1.1 log10 CFU/g (P = 0.026) vs non-polarized e-bandage treatment (no HOCl production), and 1.4 log10 CFU/g (0.0015) vs Tegaderm only controls; P. aeruginosa was similarly reduced by 1.6 log10 CFU/g (P = 0.0032) and 1.6 log10 CFU/g (P = 0.0015), respectively. For wounds infected with MRSA alone, polarized e-bandage treatment reduced bacterial load by 1.1 log10 CFU/g (P = 0.0048) and 1.3 log10 CFU/g (P = 0.0048) compared with non-polarized e-bandage and Tegaderm only, respectively. The e-bandage treatment did not negatively impact wound healing or cause tissue toxicity. The addition of systemic antibiotics did not enhance the antimicrobial efficacy of e-bandages. This study provides additional evidence for the HOCl-producing e-bandage as a novel antimicrobial strategy for managing wound infections, including in the context of antibiotic resistance and polymicrobial infections.

IMPORTANCE New approaches are needed to combat the rise of antimicrobial-resistant infections. The HOCl-producing electrochemical bandage (e-bandage) leverages in situ generation of HOCl, a natural biocide, for broad-spectrum killing of wound pathogens. Unlike traditional therapies that may exhibit limited activity against biofilms and antimicrobial-resistant organisms, the e-bandage offers a potent, standalone solution that does not contribute to further resistance or require adjunctive antibiotic ther apy. Here, we show the ability of the e-bandage to address polymicrobial infection by antimicrobial resistant clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa, two commonly isolated, co-infecting wound pathogens. Effectiveness of the HOCl-producing e-bandage in reducing pathogen load while minimizing tissue toxicity and avoiding the need for systemic antibiotics underscores its potential as a tool in managing complex wound infections.

KEYWORDS electrochemical bandage, hypochlorous acid, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, anti-biofilm, in vivo wound infection

Hypochlorous Acid: From Innate Immune Factor and Environmental Toxicant to Chemopreventive Agent Targeting Solar UV-Induced Skin Cancer

Jeremy A. Snell, Jana Jandova and Georg T. Wondrak*

Department of Pharmacology and Toxicology, R.K. Coit College of Pharmacy & UA Cancer Center, University of Arizona, Tucson, AZ, United States

A multitude of extrinsic environmental factors (referred to in their entirety as the ‘skin exposome’) impact structure and function of skin and its corresponding cellular components. The complex (i.e. additive, antagonistic, or synergistic) interactions between multiple extrinsic (exposome) and intrinsic (biological) factors are important determinants of skin health outcomes. Here, we review the role of hypochlorous acid (HOCl) as an emerging component of the skin exposome serving molecular functions as an innate immune factor, environmental toxicant, and topical chemopreventive agent targeting solar UV-induced skin cancer. HOCl [and its corresponding anion (OCl- ; hypochlorite)], a weak halogen-based acid and powerful oxidant, serves two seemingly unrelated molecular roles: (i) as an innate immune factor [acting as a myeloperoxidase (MPO)-derived microbicidal factor] and (ii) as a chemical disinfectant used in freshwater processing on a global scale, both in the context of drinking water safety and recreational freshwater use. Physicochemical properties (including redox potential and photon absorptivity) determine chemical reactivity of HOCl towards select biochemical targets [i.e. proteins (e.g. IKK, GRP78, HSA, Keap1/NRF2), lipids, and nucleic acids], essential to its role in innate immunity, antimicrobial disinfection, and therapeutic anti-inflammatory use. Recent studies have explored the interaction between solar UV and HOCl-related environmental co-exposures identifying a heretofore unrecognized photo-chemopreventive activity of topical HOCl and chlorination stress that blocks tumorigenic inflammatory progression in UV-induced high-risk SKH-1 mouse skin, a finding with potential implications for the prevention of human nonmelanoma skin photocarcinogenesis.

Keywords: hypochlorous acid, chlorination stress, environmental exposure, skin exposome, solar ultraviolet radiation, inflammation, skin cancer

The Immediate and Delayed Post-Debridement Effects on Tissue Bacterial Wound Counts of Hypochlorous Acid Versus Saline Irrigation in Chronic Wounds

John M. Hiebert, MD, FACN, FACS, and Martin C. Robson, MD, FACS, Hon. FRCS, Hon. FRACS

Truman Medical Center, University of Missouri–Kansas City; and Division of Plastic Surgery, University of South Florida, Tampa

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Keywords: ultrasonic debridement, bioburden, irrigation, hypochlorous acid, wound closure Published December 1, 2016

Introduction: Wound debridement is considered essential in chronic wound management. Hypochlorous acid has been shown to be an effective agent in reducing wound bacterial counts in open wounds. Ultrasound-enabled wound debridement is an effective and efficient method of debridement. This study compared ultrasound irrigation with hypochlorous acid versus saline irrigation for wound debridement on pre- and postoperative wounds and determined regrowth of bacteria over 1 week period of time. Finally, the outcome of definitive wound closure of the clinically clean-appearing wounds was

Methods: Seventeen consenting adult patients with chronic open wounds were randomly selected for study. The patients were randomly divided into the hypochlorous acid irrigation or saline irrigation group. All patients provided pre- and postoperative tissue samples for qualitative and quantitative bacteriology. For the time (7 days) between the debridement procedure and the definitive closure procedure, the wounds were dressed with a silver-impregnated dressing and a hydroconductive dressing. Results: Both types of irrigation in the ultrasonic system initially lowered the bacterial counts by 4 to 6 logs. However, by the time of definitive closure, the saline-irrigated wounds had bacterial counts back up to 105 whereas the hypochlorous acid–irrigated wounds remained at 102 or fewer. More than 80% of patients in the saline group had postoperative closure failure compared with 25% of patients in the hypochlorous acid group.

Conclusions: Hypochlorous acid irrigation with ultrasound debridement reduced bacterial growth in chronic open wounds more efficiently than saline alone. Postoperative wound closure outcomes suggest a remarkable reduction in wound complications after wound debridement using hypochlorous acid irrigation with ultrasound versus saline

Sodium hypochlorite body wash in the management of Staphylococcus aureus–colonized moderate-to-severe atopic dermatitis in infants, children, and adolescents

Sara Majewski MS¹ | Tanya Bhattacharya MD¹ | Manuela Asztalos MD¹ | Benjamin Bohaty MD² | Katherine C. Durham MD² | Dennis P. West PhD¹ | Adelaide A. Hebert MD² | Amy S. Paller MD¹

Abstract

Objectives: A cleansing body wash containing diluted sodium hypochlorite (0.006% NaOCl) was evaluated for management of moderate-to-severe Staphylococcus aureus–colonized, atopic dermatitis in children.

Methods: A 6-week, prospective, open-label study was conducted with 50 evaluable participants (ages 6 months to 17 years) who had moderate-to-severe atopic dermatitis with S aureus skin colonization documented by culture. Participants were instructed to continue using their current medications while using the study product, 0.006% NaOCl body wash, once daily to affected areas for 6 weeks. Primary outcome measures were Investigator's Global Assessment, Eczema Area and Severity Index, and Body Surface Area scores. Secondary outcome measures were the Visual Analog Scale for pruritus, Family Dermatology Life Quality Index, and Patient Satisfaction Questionnaire for Problem Areas. A subject daily diary and a six-item subject questionnaire that provided information on preferences for bleach bath vs body wash were secondary outcome measures.

Results: Daily use of the 0.006% NaOCl body wash led to improvement for all outcome measures comparing baseline to 2-week and to 6-week evaluations. Of the 50 skin S aureus-positive subjects, 32/50 (64%) were still positive at 2 weeks. A 36.5% decrease in subject's daily record of topical corticosteroid application at end of study compared to baseline was found. Participant surveys indicated preferences for the body wash over bleach baths.

Conclusions: Sodium hypochlorite (NaOCl) body wash improved all outcome measures for moderate-to-severe S aureus–colonized AD in infants, children, and adolescents. The limited reduction in S aureus further suggests that sodium hypochlorite has ameliorative effects other than antimicrobial actions.

KEYWORDS

atopic dermatitis, bleach, body wash, sodium hypochlorite

Activity of a hypochlorous acid‐producing electrochemical bandage as assessed with a porcine explant biofilm model

Gretchen Tibbits¹ | Abdelrhman Mohamed¹ | Suzanne Gelston¹ | Laure Flurin² | Yash S. Raval² | Kerryl E. Greenwood‐Quaintance² | Robin Patel^2,3 | Haluk Beyenal¹

Abstract

The activity of a hypochlorous acid‐producing electrochemical bandage (e‐bandage) in preventing methicillin‐resistant Staphylococcus aureus infection (MRSA) infection and removing biofilms formed by MRSA was assessed using a porcine explant biofilm model. e‐Bandages inhibited S. aureus infection (p = 0.029) after 12 h (h) of exposure and reduced 3‐day biofilm viable cell counts after 6, 12, and 24 h exposures (p = 0.029). Needle‐type microelectrodes were used to assess HOCl concentrations in explant tissue as a result of e‐bandage treatment; toxicity associated with e‐bandage treatment was evaluated. HOCl concentrations in infected and uninfected explant tissue varied between 30 and 80 µM, decreasing with increasing distance from the e‐bandage. Eukaryotic cell viability was reduced by an average of 71% and 65% in fresh and day 3‐old explants, respectively, when compared to explants exposed to nonpolarized e‐bandages. HOCl e‐bandages are a promising technology that can be further developed as an antibiotic‐free treatment for wound biofilm infections.

KEYWORDS

biofilms, chronic wounds, electrochemical bandage, hypochlorous acid, MRSA, Staphylococcus aureus

次氯酸对骨科内固定物表面细菌生物膜的清除作用

梁金正 1 ，邵欣欣 2 ，杜少华 1 ，戴双武 1

文题释义：

次氯酸：化学式HClO，是氯气溶解于水时形成的一种一价氯的含氧弱酸。在工业上，次氯酸作为家用漂白剂和清洁剂中的活性成分而广为人知。在生物学系统中，次氯酸可被视为白细胞例如中性粒细胞和单核细胞产生的毒性最强、丰度最高的氧化剂。

细菌生物膜：也称为生物被膜，是指附着于有生命或无生命物体表面被细菌胞外大分子包裹的有组织的细菌群体，存在各种主要的生物大分子如蛋白质、多糖、DNA、RNA、肽聚糖、脂和磷脂等物质。细菌生物膜多细胞结构的形成是一个动态过程，包括细菌起始黏附、细菌生物膜发展和成熟扩散等阶段。细菌生物膜对抗生素和宿主免疫防御机制的抗性很强。

摘要

背景：骨科内固定物感染中形成的细菌生物膜是临床非常棘手的问题。次氯酸作为一种高效消毒剂，可引起细菌生物膜破坏，可能对骨科内固定物感染治疗有帮助。

目的：研究次氯酸溶液体外浸泡不同时间及灌注对骨科内固定物表面细菌生物膜的清除作用。

方法：将金黄色葡萄球菌和铜绿假单胞菌分别在骨科钢板内固定物上定植3 d后形成细菌生物膜，扫描电镜下确认细菌生物膜已形成。采用次氯酸溶液分别浸泡已形成两种细菌生物膜的内固定物0，5，10，20 min及20 min+灌注6 L次氯酸和生理盐水的混合溶液(每3 L生理盐水加入120 mL次氯酸)，扫描电镜下观察细菌生物膜形态，评估次氯酸溶液对内固定物细菌生物膜的清除效果。

结果与结论：①铜绿假单胞菌：扫描电镜下可见，未经次氯酸溶液浸泡的内固定物上的细菌生物膜斑块面积大且较厚，菌落密集集中；经过次氯酸浸泡5，10，20 min后，细菌生物膜斑块面积逐渐减小并变薄，次氯酸溶液浸泡20 min+灌注6 L次氯酸和生理盐水的混合溶液可清除细菌生物膜；②金黄色葡萄球菌：扫描电镜下的表现与铜绿假单胞菌生物膜一致；③结果表明：延长浸泡时间或联合灌注可增强次氯酸对内固定物细菌生物膜的清除作用；次氯酸溶液浸泡足够时长可降解破坏内固定物上定植的细菌生物膜，清除菌落，从而达到消毒目的。

关键词：次氯酸；细菌生物膜；骨科手术；骨科内固定物；感染；消毒剂

¹南方医科大学第三附属医院骨科医学中心骨肿瘤科，广东省广州市 510630； ²中山大学附属第一医院麻醉科，广东省广州市 510080

第一作者：梁金正，男，1994 年生，广东省云浮市人，汉族，骨科住培医师，主要从事骨感染等方面研究。

通讯作者：戴双武，在读博士，主治医师，南方医科大学第三附属医院骨科医学中心骨肿瘤科，广东省广州市 510630 https://orcid.org/0000-0001-6824-5950 ( 梁金正 )

基金资助：广东省科技计划项目 (2020A1414050028)，项目负责人：戴双武

引用本文：梁金正，邵欣欣，杜少华，戴双武 . 次氯酸对骨科内固定物表面细菌生物膜的清除作用 [J]. 中国组织工程研究， 2022，26(15):2367-2371.

Liang Jinzheng1 , Shao Xinxin2 , Du Shaohua1 , Dai Shuangwu1

¹Department of Musculoskeletal Oncology, Center for Orthopedic Surgery, the Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, Guangdong Province, China; ² Department of Anesthesiology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China Liang Jinzheng, Resident of the Center for Orthopedic Surgery, the Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, Guangdong Province, China

Corresponding author: Dai Shuangwu, MD candidate, Attending physician, Department of Musculoskeletal Oncology, Center for Orthopedic Surgery, the Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, Guangdong Province, China

Abstract

BACKGROUND: Biofilm formation during the infection of orthopedic fixation devices is a very difficult clinical problem. Hypochlorous acid, as a highly effective disinfectant, can destroy the bacterial biofilm, which may be helpful for treating infection of orthopedic fixation devices.

OBJECTIVE: To study the scavenging effect of hypochlorous acid on bacterial biofilm on the surface of orthopedic fixation devices after soaking and perfusion for different time in vitro.

METHODS: Staphylococcus aureus and Pseudomonas aeruginosa were colonized on orthopedic steel fixation devices for 3 days, and then the bacterial biofilm formed, which was confirmed by scanning electron microscope. Orthopedic fixation devices with two kinds of bacterial biofilms were soaked in hypochlorous acid for 0, 5, 10, and 20 minutes, or perfused with 6 L of a mixed solution of hypochlorous acid and saline (every 3 L of saline with addition of 120 mL of hypochlorous acid) for 20 minutes. The morphology of bacterial biofilms was observed under scanning electron microscope, and the scavenging effect on the bacterial biofilm on the surface of orthopedic internal fixation devices was then evaluated.

RESULTS AND CONCLUSION: Pseudomonas aeruginosa: Under the scanning electron microscope, the bacterial biofilm plaques on the surface of the internal fixation device that was not soaked in hypochlorous acid solution were large and thick, and the colonies were densely concentrated. After 5, 10, and 20 minutes soaking in hypochlorous acid, the bacterial biofilm plaque area was gradually decreased and became thinner. Perfusion with 6 L of a mixture of hypochlorous acid and saline for 20 minutes could remove the bacterial biofilm. Staphylococcus aureus: The performance under the scanning electron microscope was  consistent with the biofilm of Pseudomonas aeruginosa. To conclude, prolonging the soaking time or a mixed perfusion can enhance the scavenging effect of hypochlorous acid on the bacterial biofilm on the surface of internal fixation devices. By soaking in hypochlorous acid for a sufficient time, the bacterial biofilm colonized on the surface of orthopedic internal fixation devices can be degraded and destroyed, thus achieving the purpose of disinfection.

Key words: hypochlorous acid; bacterial biofilm; orthopedic surgery; orthopedic internal fixation device; infection; disinfectant