Clinical Update TEN TOP TIPS Understanding and managing wound biofilm


Ten Top Tips...


Understanding and managing wound biofilm Authors:


David Keast, Terry Swanson, Keryln Carville, Jacqui Fletcher, Greg Schultz, Joyce Black.


O Author details


David Keast is Wound Care Theme Leader, WM Clinic St


Joseph’s Parkwood Hospital London, Canada. Terry Swanson is Nurse


Practitioner, South West Healthcare, Australia. Keryln Carville is Professor


Primary Health Care and Community Nursing, Silver Chain and Curtin


University, Australia. Jacqui Fletcher is Clinical Strategy Director, Welsh Wound Innovation Centre, UK. Greg


Schultz is Professor of Obstetrics and Gynecology, University of Florida,


USA. Joyce Black is Associate Professor of Nursing, University of Nebraska Medical Center, USA.


All authors are committee members of the International Wound Infection Institute and authored this update on behalf of the Institute.


For more information on the


International Wound Infection Institute email the Chair [Terry Swanson, tswanson@swh.net.au] or visit www.woundinfection-institute.com


ur understanding of the factors that delay wound


healing continues to improve through advances in research into the microenvironment. There is now strong evidence


that biofilm is present in the majority of chronic wounds.[1–4]


The pathogenesis of


biofilms continues to be evaluated, but current knowledge suggests they are detrimental to wound healing and degrade the extracellular matrix. We acknowledge that there are gaps in the evidence and significant debate continues on how best to move the current understanding forward. If we accept the premise that biofilm is


present in the majority of chronic wounds – and that it has potential to delay healing – then the clinician requires knowledge on how to identify biofilm presence and how best to manage it. Here, the International Wound Infection Institute provides ten top tips on understanding and managing would biofilm.


1


UNDERSTAND THE TERMINOLOGY TO GET THE MOST OUT OF


RESEARCH ARTICLES AND GUIDANCE DOCUMENTS


At the most basic level, a biofilm can be described as bacteria embedded in a thick, slimy barrier of sugars and proteins. The biofilm barrier protects the microorganisms from external threats.[5]


More detailed descriptions


of biofilm recognise it to be a complex microbial community that is encapsulated in an extracellular polysaccharide matrix (glycocalyx). The glycocalyx is composed of proteins, polysaccharides and extracellular DNA. The matrix of sugar and protein shields the microbial contents against the effects of the individual’s immune system and many topical and systemic antimicrobial agents. The organisms within the biofilm cannot be detected using a normal wound culture method.


20 The following terms are key to understanding


any discussion of biofilms. They are defined here specifically in the context of wound management.[6] Planktonic bacteria Free floating bacteria that are not attached to a wound surface. They are susceptible to systemic and topical antibiotics and can be detected using a normal wound culture swab.


Quorum Sensing The ability of bacteria to communicate with each other by releasing, sensing and responding to small signal molecules. This allows the bacteria to act like a multicellular organism with the ability to develop into biofilm and increase its defences and virulence.


Persister bacteria Quiescent (i.e. metabolically inactive) bacteria that are less susceptible to antibiotic therapies.


2


IDENTIFICATION: RECOGNISING BIOFILM IS A COMPLEX,


SPECIALIST TASK


Specialised microscopic techniques used since 2008, have allowed several research groups to demonstrate that 60% to 90%[7]


have biofilm formation.[1–3,8,9] Currently, the only definitive techniques


available to detect biofilm involve advanced microscopy or specialised culture techniques. Microbiologists and researchers have used several microscopy methods to identify structures that are characteristic of biofilms such as epifluorescence microscopy, confocal laser scanning microscopy, scanning electron microscopy, and light microscopy [FIGURE 1].[10] As standard clinical microbiology culturing


procedures only detect planktonic bacteria, special procedures must be used to culture bacteria that are present in biofilms. Typically, samples are initially treated for 24 hours in antiseptic solutions that rapidly kill all planktonic bacteria (such as brief exposure to dilute bleach) the neutralised biofilm communities are physically dispersed with ultrasonic energy and cultured on nutrient agar plates to quantitate levels of biofilm bacteria.[11]


Wounds International Vol 5 | Issue 2 | ©Wounds International 2014 | www.woundsinternational.com of chronic wounds


Ten Top Tips


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