The impact of mental models on the treatment and research of chronic infections due to biofilms

Establishment of Streptococcus suis Biofilm Infection Model In Vivo and Comparative Analysis of Gene Expression Profiles between In Vivo and In Vitro Biofilms

Streptococcus suis is a zoonotic pathogen that continuously threatens animal husbandry and public health worldwide. Studies have shown that S. suis can cause persistent infection by forming biofilms. In this study, a model of S. suis biofilm-related infection was successfully constructed for the first time by simulating the natural infection of S. suis, and biofilm of S. suis in vivo was successfully observed in the lung tissue of infected pigs by a variety of detection methods. Subsequently, selective capture of transcribed sequences (SCOTS) was used to identify genes expressed by S. suis in vivo biofilms. Sixty-nine genes were captured in in vivo biofilms formed by S. suis for the first time by SCOTS; they were mainly involved in metabolism, cell replication, and division, transport, signal transduction, cell wall, etc. Genes related to S. suis in vitro biofilm formation were also identified by SCOTS and RNA sequencing. Approximately half of the genes captured by SCOTS in the in vivo and in vitro biofilms were found to be different. In summary, our study provides powerful clues for future exploration of the mechanisms of S. suis biofilm formation. IMPORTANCE Streptococcus suis is considered an important zoonotic pathogen, and persistent infection caused by biofilm is currently considered to be the reason why S. suis is difficult to control in swine. However, to date, a model of the biofilm of S. suis in vivo has not been successfully constructed. Here, we successfully detected biofilms of S. suis in vivo in lung tissues of piglets infected with S. suis. Selective capture of transcribed sequences and the transcriptome were used to obtain gene profiles of S. suis in vivo and in vitro biofilms, and the results showed large differences between them. Such data are of importance for future experimental studies exploring the mechanism of biofilm formation by S. suis in vivo.

Establishing a consensus on wound infection definitions

OBJECTIVES

The aim of this study was to establish an international, interorganisational consensus on wound infection terminology.

METHODS

This project consisted of definition scoping and a Delphi process to produce a consensus glossary for 18 wound infection terms. Recent guidelines/consensus documents were reviewed to identify 2-4 definitions for each term. An online consensus process was undertaken using the RAND Appropriateness Method, a consensus method for panels to reach agreement. International wound organisations nominated experts to participate, from whom 21 participants were selected to represent different organisations, geographic regions and disciplines. In the first consensus round, each term was presented alongside 2-3 definitions and participants nominated their preferred definition, with the majority vote used to select a baseline definition. The consensus process then proceeded, with participants using a 9-point Likert scale to score their level of agreement or disagreement with the definition for each term. Participants also provided a justification outlining the reason behind their rating. At the end of each round, an index was calculated to provide a quantitative evaluation indicating whether agreement or disagreement had been reached.

RESULTS

Reasoning statements were summarised and the definitions were adjusted to incorporate concepts identified by participants. The adjusted definition was presented in the next consensus round, together with the reasoning statements. Terms for which a final definition was not achieved in three consensus rounds were finalised with preferential voting using 2-3 definitions that had reached consensus.

PROJECT PROGRESS AND SIGNIFICANCE

The project generated a glossary of wound infection terms, endorsed through participation of 15 international organisations, for dissemination of guidelines and clinical decision-making/teaching tools.

The biofilm life cycle: expanding the conceptual model of biofilm formation

Bacterial biofilms are often defined as communities of surface-attached bacteria and are typically depicted with a classic mushroom-shaped structure characteristic of Pseudomonas aeruginosa. However, it has become evident that this is not how all biofilms develop, especially in vivo, in clinical and industrial settings, and in the environment, where biofilms often are observed as non-surface-attached aggregates. In this Review, we describe the origin of the current five-step biofilm development model and why it fails to capture many aspects of bacterial biofilm physiology. We aim to present a simplistic developmental model for biofilm formation that is flexible enough to include all the diverse scenarios and microenvironments where biofilms are formed. With this new expanded, inclusive model, we hereby introduce a common platform for developing an understanding of biofilms and anti-biofilm strategies that can be tailored to the microenvironment under investigation.

Embedding Wound Hygiene into a proactive wound healing strategy

Foreword. Wound Hygiene: the next stage

Since a panel published the first consensus document on Wound Hygiene in March 2020, there has been a flurry of activity in support of this newly established concept in proactive wound healing. 1 The document concluded that all wounds, particularly hard-to-heal ones, will benefit from Wound Hygiene, which should be initiated at the first referral, following a full holistic assessment to identify the wound aetiology and comorbidities, and then implemented at every dressing change until full healing occurs. 1 The consensus has since been bolstered by educational webinars; competency-based skills training and support; development of international Wound Hygiene ambassadors; a survey of 1478 respondents, published in July 2021; 2 and a case study supplement, published in January 2022, featuring a range of wound types, anatomies and underlying conditions on the improvements in wound-healing progress that can be achieved. 3 Wound Hygiene has gained its own identity and is now a term in and of itself, that encompasses a 4-step protocol of care. It is an antibiofilm approach that is increasingly being used across wound care. The results of the survey 2 were particularly encouraging for seeing how far Wound Hygiene has come, and how quickly: More than half (57.4%) had heard of the concept of Wound Hygiene Of those, 75.3% have implemented Wound Hygiene Overall, following implementation of Wound Hygiene, 80.3% of respondents reported improved healing rates. 2 However, the top three barriers identified by the survey—lack of confidence, competence and research data—show that there is more to be done to support Wound Hygiene in practice. 2 As a result, a consensus panel of international key opinion leaders convened virtually in the summer of 2021 to discuss what has been done so far, the outputs of the survey, and ideas for addressing the unmet needs identified by the results. The result is this publication, which represents an addendum to the initial consensus document, broadening support for implementation of Wound Hygiene. This document will reflect on the reasons Wound Hygiene has been successful in its first two years of implementation, reiterating its DNA: Do not wait to treat hard-to-heal wounds Use a simple 4-step approach Enable all healthcare professionals to implement and use Wound Hygiene. The document will also discuss the evolution of the Wound Hygiene concept, focusing on how and when to implement Wound Hygiene on all tissue types of hard-to-heal wounds, and proposing what these are. The panel has expanded the framework in which Wound Hygiene is used, with the ultimate objective of introducing the concept of ‘embedding Wound Hygiene intro a proactive wound healing strategy.’ Key inefficiencies are often observed along the journeys of people living with hard-to-heal wounds. The limited number of specialised healthcare professionals and the resulting delays in reaching them may increase the likelihood of a hard-to-heal wound developing. In a world where so much is happening so quickly that we may, at times, feel powerless to drive change, the panel wants to provide further guidance to propel the use of Wound Hygiene. The concept of Wound Hygiene is resonating, and the panel wants you to know that in whatever region you work, in whatever area of clinical practice, you are enabled to make this change. Wielding the 4-step Wound Hygiene protocol consistently is a key action every healthcare professional in every care setting can take to tackle the global wound care crisis. Wound Hygiene has taken off—now, where do we want to land? In a place where Wound Hygiene is practised on all wounds, at every stage, until healing. The panel once again recognises that the community of global healthcare providers should consider their local standards and guidelines when applying the recommendations of this document. To this end, the panel has created a flexible 3-phase framework that situates Wound Hygiene as integral to proactive wound healing. The panel hopes you will continue to implement Wound Hygiene and see the benefits it can bring to people living with wounds, as well as those who care for them.

Non-doped and transition metal-doped CuO nano-powders: structure-physical properties and anti-adhesion activity relationship

Bacterial contamination and biofilm formation generate severe problems in many fields. Among these biofilm-forming bacteria, Staphylococcus epidermidis (S. epidermidis) has emerged as a major cause of nosocomial infection (NI). However, with the dramatic rise in resistance toward conventional antibiotics, there is a pressing need for developing effective anti-biofilms. So, fabrication of copper oxide nanoparticles (NPs) is one of the new strategies to combat biofilms. Notably, doped CuO NPs in anti-biofilm therapy have become a hot spot of attention in recent years due to their physicochemical properties. In this context, the present work deals with the investigation of undoped and transition metal (TM)-doped CuO NPs (TM = Zn, Ni, Mn, Fe and Co), synthesized via the co-precipitation method. The synthesized CuO NPs are characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Results consistently revealed the successful formation of CuO NPs using the co-precipitation method and confirmed that TM ions are successfully inserted into CuO crystal lattice. We found that doping changes the morphology of the CuO NPs and increases their crystallite size. The XPS results show a non-uniform distribution of the doping concentration, with a depletion or an enrichment of the NP surface depending on the element considered. Furthermore, the anti-adhesive potential of CuO NPs against S. epidermidis S61 biofilm formation is evaluated in this study by crystal violet and fluorescence microscopy assays. All synthesized NPs exhibit considerable anti-adhesive activity against S. epidermidis S61 biofilm. Interestingly, compared to undoped CuO, Fe and Ni-doped oxides show an improved activity when used at high concentrations, whereas Mn-doped CuO is the most efficient at low concentrations. This makes TM-doped CuO a promising candidate to be used in biomedical applications.

Bacterial contamination and biofilm formation generate severe problems in many fields.