Practice development
Ensuring that the correct antimicrobial dressing is selected
Authors: David Keast, Christina Lindholm
This article examines the various tools available to clinicians in the fight against the increase of antiobiotic resistance in bacteria and the environmental hazards associated with antibiotics. The importance of employing an effective wound assessment during diagnosis is emphasised, while the selection of antiseptic dressings should always be based on an assessment of the microbial burden in the wound, the wound type and the location and condition of the wound.
INTRODUCTION The skin is the largest organ in the body. It has multiple functions including acting as a passive barrier against foreign substances, bacteria and irradiation. It also acts as a dynamic barrier through thermoregulation, the exchange of gases and immune surveillance. When skin failure occurs, these functions are compromised. All open wounds contain microorganisms,
yet the majority are not infected. Wound infection depends on the number of invading organisms present, their virulence and the ability of the host to manage the bacterial load. The spectrum of interactions between the microbial community are shown inTable 1[1]
. The host may gradually reach a point at
which wound healing is impaired. At this point, immediate intervention to pre-empt infection is required[2]
. Bacterial biofilms are now considered to be
one of the key contributors to chronic wound pathogenesis and ‘hard to heal’ recalcitrance, alongside hypoxia, ischaemia-reperfusion injury and intrinsic host factors[3, 4]
. Biofilm Useful links
Biofilms Made Easy Prontosan Made Easy
Antimicrobial Dressings Made Easy
development involves a cycle of attachment — growth involving persister cells and the detachment of planktonic phenotypes. The rate of biofilm formation in chronic wounds can be rapid and the prevalence of biofilms in chronic wounds can be high[5]
. In one study,
30 out of 50 chronic wounds were reported to contain biofilms[6]
. Biofilms are regarded as non-visible to the 22 Wounds International Vol 3 | Issue 3 | ©Wounds International 2012 naked eye. However, Wolcott et al[5] described
visible signs of macroscopic manifestations — translucent or opaque gel-like material — that were responsive only to selective treatments[7]
.
This has not been proven by confirmatory molecular techniques, such as polymerase chain reaction (PCR), confocal or scanning electron microscope (SEM) microscopy, and an accurate diagnostic is eagerly awaited. Any factor that impairs the ability of the host to
mount a response to bacteria in an open wound increases the risk of infection. These factors may include co-morbid conditions, such as obesity, renal failure, diabetes, collagen, vascular disorders, malignancy and anaemia. Medications that suppress immune function such as corticosteroids and chemotherapeutic agents also increase the risk of infection. Poor tissue perfusion is a key risk factor for
infection. Wound-related factors may include the presence of necrotic tissue or a foreign body, prolonged duration, large size or depth and anatomical location. Patient factors, such as poor hygiene and treatment choices, must also be considered. Tasks that are inadequately performed by carers, such as poor hand hygiene or dressing techniques, may put the patient at risk. The clinician must consider all of these factors and develop strategies to mitigate them in order to reduce the risk of infection.
RECOGNISING AN INFECTED WOUND The diagnosis of wound infection is primarily
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