Combatting wound biofilm and recalcitrance with a novel anti-biofilm Hydrofiber® wound dressing

AbstractBackgroundBiofilm is an impediment to wound healing as a consequence of its proven ability to impair epithelialization, granulation tissue formation and normal inflammatory processes, as well as protecting wound pathogens from antibiotics and antiseptics. With this in mind, a project was initiated to develop a combined anti-biofilm/antimicrobial technology that could be incorporated into a wound dressing to maximize effectiveness against wound pathogens existing in their predominant biofilm form.MethodsInitially, a wide range of anti-biofilm agents in combination with ionic silver were screened in a rapid throughput in vitro biofilm model. Selected agents were incorporated into a new wound dressing format and subsequently tested in vitro against antibiotic-resistant pathogens in their most tolerant biofilm form.ResultsThe combination of ionic silver with a metal chelating agent and a surfactant was shown to produce a synergistic effect (referred to as Ag+ Technology) that substantially improved the antimicrobial efficacy of ionic silver against biofilm pathogens in a simulated wound biofilm model.ConclusionBy combining anti-biofilm and antimicrobial components that work in synergy to disrupt biofilm and expose associated wound pathogens to the antimicrobial action of ionic silver, it is anticipated that this new technology incorporated into an advanced Hydrofiber® wound dressing will contribute significantly to managing biofilm infections and encouraging healing in patients debilitated by recalcitrant wounds

A Three-Dimensional Model of Bacterial Biofilms and Its Use in Antimicrobial Susceptibility Testing

(1) Background: The discrepant antimicrobial susceptibility between planktonic and biofilm bacterial modes poses a problem for clinical microbiology laboratories and necessitates a relevant 3D experimental model allowing bacteria to grow in biofilm mode, in vitro, for use in anti-biofilm susceptibility testing. (2) Methods: This work develops a 3D biofilm model consisting of alginate beads containing S. aureus biofilm and encased within two thick layers of alginate matrix. The constructed model was placed on a thin Boyden chamber insert suspended on a 24-well culture plate containing the culture medium. The antibacterial activity of bacitracin and chlorhexidine digluconate (CD), either combined or separately, against 2D S. aureus culture was compared to that in the 3D biofilm model. Quantitative analysis and imaging analysis were performed by assessing the bacterial load within the matrix as well as measuring the optical density of the culture medium nourishing the matrix. (3) Results: The 3D biofilm model represented the typical complex characteristics of biofilm with greater insusceptibility to the tested antimicrobials than the 2D culture. Only bacitracin and CD in combination at 100× the concentration found to be successful against 2D culture were able to completely eliminate the 3D biofilm matrix. (4) Conclusions: The 3D biofilm model, designed to be more clinically relevant, exhibits higher antimicrobial insusceptibility than the 2D culture, demonstrating that the model might be useful for testing and discovering new antimicrobial therapies. The data also support the view that combination therapy might be the optimal approach to combat biofilm infections

Characterisation of biofilm structure: investigation and methods for developing strategies for control and prevention of infections

The addition of antimicrobial agents to wound dressings is used to reduce the risk of wound infection, and help manage local wound infections, thereby facilitating wound progression, but their activity is impeded by biofilm tolerance. The aim of this work was to investigate the structure and development of wound pathogen biofilm, and to design a novel, challenging in vitro simulated chronic wound biofilm model to evaluate the antimicrobial and anti-biofilm effectiveness of several current wound dressings. This study demonstrates how rapidly biofilm can form on a model wound that has been contaminated by contact with planktonic bacteria, producing structured bacterial biofilm communities with nutrient and waste channels and the dispersal of bacterial cells at the surface. Light Microscopy (LM), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) provided structural images of both biofilm formation and the presence of individual bacteria within the biofilm structure. After 24-48 hours, biofilm had become established, and dispersal of biofilm bacteria was visualised as early as 48 hours. By applying various dressings to the model and analysing representative fields of vision, biofilm was observable to varying extents beneath most of the dressings tested after 24 hours, and by 72 hours this had increased. Two dressings appeared to help prevent the growth of biofilm: a hydrated microbial cellulose dressing containing polyhexamethyl biguanidine dressing, and a next-generation antimicrobial dressing containing ionic silver in an anti-biofilm formulation. The results highlight the importance of dressing selection to manage biofilm in chronic and acute wounds, and these observations should help in the development of novel and effective control of wound infection

Wound infection in clinical practice : principles of best practice

The International Wound Infection Institute (IWII) is an organisation of volunteer interdisciplinary health professionals dedicated to advancing and improving practice relating to prevention and control of wound infection. This includes acute wounds (surgical, traumatic and burns) and chronic wounds of all types, although principally chronic wounds of venous, arterial, diabetic and pressure aetiologies. Wound infection is a common complication of wounds. It leads to delays in wound healing and increases the risk of loss of limb and life. Implementation of effective strategies to prevent, diagnose and manage, is important in reducing mortality and morbidity rates associated with wound infection. This second edition of Wound Infection in Clinical Practice is an update of the first edition published in 2008 by the World Union of Wound Healing Societies (WUWHS). The original document was authored by leading experts in wound management and endorsed by the WUWHS. The intent of this edition is to provide a practical, updated resource that is easy-to-use and understand. For this edition, the IWII collaborative team has undertaken a comprehensive review of contemporary literature, including systematic reviews and meta-analyses when available. In addition, the team conducted a formal Delphi process to reach consensus on wound infection issues for which scientific research is minimal or lacking. This rigorous process provides an update on the science and expert opinion regarding prevention, diagnosis and control of wound infection. This edition outlines new definitions relevant to wound infection, presents new paradigms and advancements in the management and diagnosis of a wound infection, and highlights controversial areas of discussion

Elektrospinnitud antimikroobsete PCL ja PCL/PEO nanofiibermattide in vitro testimine

Liigne antibiootikumide kasutamine on viinud patogeensete bakterite antibiootikumresistentsuse suurenemisele ning seetõttu on vaja vähendada antibiootikumide kasutamist. Süsteemse manustamise asenduseks töötatakse välja erinevaid alternatiive, millest üks on elektrospinnitud antimikroobsed haavakatted infitseerunud haava lokaalseks raviks. Farmakopöa juhiste puudumise tõttu uudsete ravimvormide testimiseks analüüsiti käesolevas magistritöös erinevate raviaine vabanemisprofiilidega PCL/CAM ja PCL/PEO/CAM nanofiibermattide antimikroobsust bioreporteriga, in vitro ja ex vivo infektsioonimudelitega ning hinnati bakterite arvukust Alamar Blue värvi abil. Nimetatud katsed komplementeerivad farmakopöa kvaliteedikontrolli teste ning nende abil on võimalik hinnata nanofiibermattide bioloogilisi toimei

Biofilmes e antimicrobianos

A formação de biofilmes é atualmente reconhecido como um dos fatores mais relevantes nas infeções crónicas. Estes são comunidades bacterianas agregadas, envolvidas numa matriz polimérica extracelular, com capacidades de adesão a superfícies bióticas e abióticas. A formação de um biofilme ocorre geralmente em várias etapas consecutivas. As características importantes das infecções crónicas baseadas em biofilmes são a extrema resistência e tolerância aos antibióticos e a muitos outros agentes antimicrobianos convencionais bem como a capacidade extrema para evitar as defesas do hospedeiro. Deste modo, é urgente as pesquisas e os avanços da ciência bem como da tecnologia nesta área com o intuito de adquirir métodos mais rápidos para o diagnóstico dos biofilmes e consequente eficácia na terapêutica. O tratamento de infeções por biofilmes é atualmente um desafio difícil e complicado para microbiologistas, clínicos, médicos e enfermeiros. Deste modo, é relevante conceber um algoritmo de atuação para controlo dos biofilmes no sentido de auxiliar os profissionais de saúde, e que permita também otimizar a identificação de biofilmes e terapêutica dos mesmos na prática clínica. Como se explica a existência de biofilmes? Qual a necessidade de distinguir o paradigma plantónico do paradigma séssil? O paradigma séssil deverá ter mais relevância na clínica? Como combater este grave problema de saúde pública?Nowadays the formation of biofilms is recognized as one of the most relevant factors in chronic infections. Biofilms are aggregated bacterial communities, envolved in a polymeric extracellular matrix, with capability to adhere to abiotic and biotic surfaces. The formation of a biofilm, generally occurs in various sequential steps. The important characteristics of chronic infections based in biofilms are the extreme resistance and tolerance to antibiotics and many other conventional antimicrobial agents, as well as the extreme capability to evade the host's immune system. In this manner, the researchs and scientific advancements as well as technological improvements are urgent, in order to acquiry faster methods for biofilm diagnosis and treatment efficacy. Currently, the treatment of biofilm infections is difficult and complicated for microbiologists, doctors, practitioners and nurses. Therefore, it's relevant to conceive an algorithm for biofilm control, to auxiliate health care assistants, and to also permit biofilm identification and treatment in clinical practice. How do we explain biofilm existence? What's the necessity to differentiatite the sessile and platonic paradigms? Is the sessile paradigm more relevant clinically? How to overcome this serious public health problem

Biofilmes e antimicrobianos

A formação de biofilmes é atualmente reconhecido como um dos fatores mais relevantes nas infeções crónicas. Estes são comunidades bacterianas agregadas, envolvidas numa matriz polimérica extracelular, com capacidades de adesão a superfícies bióticas e abióticas. A formação de um biofilme ocorre geralmente em várias etapas consecutivas. As características importantes das infecções crónicas baseadas em biofilmes são a extrema resistência e tolerância aos antibióticos e a muitos outros agentes antimicrobianos convencionais bem como a capacidade extrema para evitar as defesas do hospedeiro. Deste modo, é urgente as pesquisas e os avanços da ciência bem como da tecnologia nesta área com o intuito de adquirir métodos mais rápidos para o diagnóstico dos biofilmes e consequente eficácia na terapêutica. O tratamento de infeções por biofilmes é atualmente um desafio difícil e complicado para microbiologistas, clínicos, médicos e enfermeiros. Deste modo, é relevante conceber um algoritmo de atuação para controlo dos biofilmes no sentido de auxiliar os profissionais de saúde, e que permita também otimizar a identificação de biofilmes e terapêutica dos mesmos na prática clínica. Como se explica a existência de biofilmes? Qual a necessidade de distinguir o paradigma plantónico do paradigma séssil? O paradigma séssil deverá ter mais relevância na clínica? Como combater este grave problema de saúde pública?Nowadays the formation of biofilms is recognized as one of the most relevant factors in chronic infections. Biofilms are aggregated bacterial communities, envolved in a polymeric extracellular matrix, with capability to adhere to abiotic and biotic surfaces. The formation of a biofilm, generally occurs in various sequential steps. The important characteristics of chronic infections based in biofilms are the extreme resistance and tolerance to antibiotics and many other conventional antimicrobial agents, as well as the extreme capability to evade the host's immune system. In this manner, the researchs and scientific advancements as well as technological improvements are urgent, in order to acquiry faster methods for biofilm diagnosis and treatment efficacy. Currently, the treatment of biofilm infections is difficult and complicated for microbiologists, doctors, practitioners and nurses. Therefore, it's relevant to conceive an algorithm for biofilm control, to auxiliate health care assistants, and to also permit biofilm identification and treatment in clinical practice. How do we explain biofilm existence? What's the necessity to differentiatite the sessile and platonic paradigms? Is the sessile paradigm more relevant clinically? How to overcome this serious public health problem

Biofilmes e feridas crónicas

As feridas crónicas são um problema de saúde relevante em todo o mundo. Para garantir a cicatrização é necessário controlar fatores como a infeção a relevância dos biofilmes e o papel destes na cicatrização. Os biofilmes funcionam como sistemas biológicos formados por comunidades de microrganismos agregados, organizados e funcionais embebidos numa matriz exopolissacarídica. A formação de um biofilme ocorre geralmente em várias etapas consecutivas. A resistência antimicrobiana tornou-se uma das mais eminentes ameaças para a saúde global e uma preocupação crescente para os especialistas em saúde. Muitas infeções tornaram-se resistentes aos antimicrobianos usados para as tratar, resultando em elevadas taxas de mortalidade. Uma vez que, as resistências individuais são já um problema universal, é possível inferir que o paradigma séssil é ainda mais problemático, pois representa um somatório de resistências que permite ao biofilme ser substancialmente mais resistente à ação de antimicrobianos do que as células que estão em estado planctónico. A fraca penetração e difusão dos antimicrobianos através da matriz polisacarídica, a forma específica como os microorganismos se organizam no biofilme são algumas das hipóteses explicativas para o aumento da resistência individual e coletiva (biofilmes) aos antimicrobianos. O diagnóstico e a terapêutica das infeções causadas por biofilme é um processo difícil, daí haver um reforço na importância da prevenção. Deste modo, as feridas crónicas apresentam-se como um desafio à qualidade de vida dos doentes, à abordagem efetuada pelos profissionais de saúde e aos recursos despendidos pelas instituições de saúde no seu tratamento. Assim sendo, é relevante propor um algoritmo síntese que possa ser facilitador na gestão, por parte dos profissionais de saúde, dos biofilmes nas feridas. Como se explica a existência de feridas crónicas? Qual a importância do paradigma séssil para explicar os sinais e sintomas que caracterizam as infeções crónicas? Que dinâmica de investigação existe atualmente para apresentar soluções para este grave problema de saúde pública?Chronic wounds are a major health problem all around the world. To ensure healing is necessary to control factors such as infection, the relevance of biofilms and their role in healing. Biofilmes can be defined as biological systems formed by communities of aggregated, organized and functional cells embedded in exopolimeric matrix. The biofilm formation usually occurs in several stages. The antimicrobial resistance has become one of the most eminent threats to global health and a rising concern for healthcare specialists. Many common infections are becoming resistant to the antimicrobial drugs used to treat them, resulting in higher mortality rates. Once the individual resistances are already a universal problem, it can be inferred that the sessile paradigm is even more problematic because it is a summation of resistances allowing the biofilm to be substantially more resistant to the action of antimicrobials than those cells grown planctonically. The low penetration and dissemination of antimicrobial agents through the polysaccharide matrix and the specific way in which the microorganisms are organized in biofilms are some of the hypotheses proposed to explain the increasing individual and collective (biofilms) antimicrobial resistance. The diagnosis and treatment of biofilm infections caused by biofilms is a difficult process, that’s why prevention is really important. This way, chronic wounds appear as a challenge to the patients’ quality of life, the approach made by health professionals and resources spent by health institutions in their treatment. Therefore, it is important to propose a synthesis algorithm that can be a help in the management of biofilms in wounds by health professionals. How do you explain the existence of chronic wounds? How important is the sessile paradigm to explain the signs and symptoms that characterize chronic infections? What dynamic research currently exists to provide solutions to this serious public health problem

Microbial Biofilms

In the book Microbial Biofilms: Importance and applications, eminent scientists provide an up-to-date review of the present and future trends on biofilm-related research. This book is divided with four subdivisions as biofilm fundamentals, applications, health aspects, and their control. Moreover, this book also provides a comprehensive account on microbial interactions in biofilms, pyocyanin, and extracellular DNA in facilitating Pseudomonas aeruginosa biofilm formation, atomic force microscopic studies of biofilms, and biofilms in beverage industry. The book comprises a total of 21 chapters from valued contributions from world leading experts in Australia, Bulgaria, Canada, China, Serbia, Germany, Italy, Japan, the United Kingdom, the Kingdom of Saudi Arabia, Republic of Korea, Mexico, Poland, Portugal, and Turkey. This book may be used as a text or reference for everyone interested in biofilms and their applications. It is also highly recommended for environmental microbiologists, soil scientists, medical microbiologists, bioremediation experts, and microbiologists working in biocorrosion, biofouling, biodegradation, water microbiology, quorum sensing, and many other related areas. Scientists in academia, research laboratories, and industry will also find it of interest