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What is a wound infection?

What is a Wound Infection and the various terminologies are introduced.
Hello and welcome to this session, wound infection and management. We’re going to discuss what is a wound infection. And probably the most important thing to commence with is to define a wound infection. We can speak to many colleagues, any type of health care professional, and patients and their relatives, and everybody will give a slightly different definition. However, the definition we should be working to is that wound infection is the invasion of a wound by proliferating microorganisms to a level that invokes a local and / or a systemic response in the host. The presence of these microorganisms in the wound can cause local tissue damage and then impedes and slows down the wound healing process.
Intervention is then required to assist the host defences in destroying those invading microorganisms. We do have wound infection containment as well that can help staff and all health care professionals to identify when we should and should not be using antimicrobial wound dressings and antibiotics. What is probably one of the most important things to remember is that we don’t use antibiotics or antimicrobials for a just in case scenario. And by that I mean we think, I’ll just put an antimicrobial wound dressing on this wound just in case it should become infected. We should only be using these products when there is clear signs and symptoms of a wound infection.
This wound infection continuum that you can see in front of you now was produced by the International Wound Infection Institute after an in-depth Delphi survey, an exploration of the research and evidence underpinning management and prevention of wound infection. As you can see here, we have biofilm across the top that quite clearly identifies that a biofilm is probably only present on the wound bed from the stage of local infection to systemic infection. But this increasing microbial virulence and increasing numbers of microbes gets larger and larger as the patient’s health and wound goes through a wound infection. There are different terminologies as well that you need to be aware of when trying to describe and define a wound infection.
These are identified at the bottom as contamination, colonisation, local infection, spreading infection, and systemic infection. And again, please look at the arrows below these terminologies as well. So if the patient has a contaminated or a colonised wound, we just need vigilance, so to continue caring for the patient normally, cleaning the wounds, applying the wound dressings, and looking after the patient holistically, but no antimicrobials will be indicated. However, if there are signs of local infection or spreading or systemic infection, then you need to be thinking about an intervention, which could be topical antimicrobials or systemic and topical antimicrobials. These terms are important that you remember them.
And also this document is in the resource section for you as well at this session. But please ensure if you go online to get hold of it, you do download the 2016 version. Prior to this there was a term called critical colonisation within the document. This has now been removed due to lack of research and evidence supporting this definition. Now for a contaminated wound, what we’re talking about is a wound that is contaminated in the presence of non-proliferating microbes at a level that does not invoke a host response. No issues with that were all contaminated, so there’s nothing to worry about. Colonisation refers to presence within the wound of a microbial organism that undergoes limited proliferation.
And again, there is not normally a host reaction here. So microbial growth occurs at a non-critical level, and the wound healing isn’t delayed, and it’s not affected, so we don’t really need to be bothered about that. What we do become concerned about is when we get to a local infection. And this is when bacteria or other microbes move deeper into the wound tissue. And these proliferate or grow at a rate that then does invoke a response in the host. This local infection can be contained in one location system or structure, but especially in chronic wounds, local infection is often seen as those subtle signs that can be considered covert signs of infection that we’ll look at later.
They can then develop into classical overt signs of infection. Spreading infection describes the invasion of the surrounding tissue by the infective organisms that spread from a wound. These microorganisms, as you probably suspect, proliferate and spread to a degree that would get signs and symptoms of wound infection beyond the wound border, and we’re looking at peri-wound area as well. The spreading infection can involve the deep tissue, the muscle fascia, organs, or body cavities. And the final word that you’re looking at here is systemic infection. And this is when the wound affects the body as a whole. So microorganisms spread throughout the body by the vascular lymphatic systems. We get a systemic inflammatory response that can lead to sepsis and organ dysfunction.
And ultimately the patient may die. So we really do want to avoid systemic infection. The terms here, again, for you are contamination, colonisation, local infection, spreading infection, and systemic infection. We’ve just discussed these in the previous slide. But again, if you look at the International Wound Infection Institute’s Best Practice document of 2016, you’ll be able to see these in more depth and more of a definition of them as well, if you were interested. This slide in front of you, as well, although busy, does quite clearly define all the terms that we’ve just been talking about. What I would like to draw your eyes to is the local infection section.
You can see here, we’ve identified the covert signs of infection and the overt signs of infection. So covert are very subtle signs of local infection that you need to be aware of. Overt signs are ones that you can see that are more classical. Please ensure that when you’re trying to identify these, ask the patients, as well, how are you feeling? Have you got any pain? Do you feel generally unwell? Take the temperature. Have they got a pyrexia? Because that can be indicative of a wound infection, as well. And is there any malodour? Smell is a great indicator that something is not quite right.
If you do identify any of these, make sure you document everything you see and report to the correct people. It could be the nurse in charge. It could be the physician. Or you may need to get microbiologists as well, involved. But please make sure you document everything and you re-evaluate regularly. Wound infections themselves can cause pain for the patient and cause a pyrexia and delayed wound healing, which as well as the excessive costs associated with having to manage a wound infection from using antibiotics and antimicrobial wound dressings, probably more importantly is the effects on the quality of life it has for the patient.
If you have excessive pain, or you’ve got malodour, you don’t want to go out, you don’t want to socialise, which can then lead to depression. Similarly, you may have to stay in hospital for a longer period of time, where you feel socially isolated. So we don’t want a wound infection for a range of different reasons. But also we want the wound to heal in a timely fashion, so patients can get back to their normal activities of daily living. The World Health Organisation has published a range of papers as well.
But they have been very clear that we need to look at how do we use antimicrobial therapy correctly and appropriately, because there is a threat of resistance across the world to this. And we don’t want to lose our first line of treatment in preventing and managing wound infections. However, after defining wound infection and discussing how we best are able to recognise when the single most way to prevent the spread of infection is handwashing and effective handwashing. The NHS in the UK has provided some very clear guidance on the best handwashing technique available with soap and water. You can see this on the screen in front of you.
But also in the resource section, there is a session there that you can have a look at. This should be shared with all health care professionals, but also shared with the patients and carers, as well. So if the patient is being nursed at home, then it’s well worth talking to the carers about how to wash their hands as well and ensure that they’ve got soap nearby the basins and there is access to warm water. So even though it is simple, sometimes people don’t all remember to wash their hands adequately. So this is really important that everybody is informed.

Wound infection is the invasion of a wound by proliferating microorganisms to a level that invokes a local and/or systemic response in the host. The presence of microorganisms within the wound causes local tissue damage and impedes wound healing.

In this video, Professor Karen Ousey describes the terminologies associated with wound infection.

Wound infections can cause:

• Pain

• Pyrexia

• Delayed wound healing

• Additional costs associated with antibiotic usage

To prevent this, it is crucial to implement aseptic techniques of wound care.

Pressure ulcer lumbar region displaying locoregional infection with Pseudomonas aeruginosa.

Pressure ulcer lumbar region displaying locoregional infection with Pseudomonas aeruginosa.

Hands are the main pathways of infection during health care. Hand washing is therefore the most important measure to avoid the transmission of harmful pathogens and prevent health care-associated infections. The NHS website provides guidelines on how to wash your hands effectively, and this can be found here.

Additionally, watch this training video by WHO showing the steps to hand-washing with soap and water:

This is an additional video, hosted on YouTube.

Please access and review the paper on principles of best practice by the International Wound Infection Institute.

This article is from the free online

Antimicrobial Stewardship in Wound Management

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