Formulary

Infected wounds

First Line
Second Line
Specialist
Hospital Only

Diagnosing wound infection is a clinical judgement. Micro-organisms are contained in all wounds however the majority do not become infected.

An increased level of suspicion for the likelihood of wound infection should be maintained in patients with:

  • Diabetes Mellitus
  • Autoimmune disease
  • Hypoxia/poor tissue perfusion
  • Immunosuppression

Wound management strategies must aim to provide optimal wound healing conditions

  • Antibiotic use should be limited to specific clinical situations (e.g. overt infections) and directed to susceptible organisms
  • Wound status must be regularly reviewed, and management strategies changed when progress towards healing is not achieved
  • Prescribing of antibiotics should adhere to employing organisation's policies and local Joint Formularies. Doses need to be of a therapeutic level and for sufficient duration

Topical antibiotic preparations are used to reduce levels of bacteria within the wound bed and in burns to prevent infection. They are frequent sensitisers, can encourage the development of resistant bacteria and have no effect on healing. Therefore, their use should be carefully restricted.

Please see 13.10.1 Antibacterial preparations

Swabs

Wound swabs should be taken following wound cleansing (and debridement if appropriate) from wounds which are critically colonised or clinically infected. The following wound types should be swabbed:

  • Acute wounds with signs of infection
  • Chronic wounds with signs of spreading or systemic infection
  • Critically colonised / locally infected wounds that have not responded to or are deteriorating despite appropriate topical antimicrobial treatment

The swab result is to confirm that the antibiotic regime is the appropriate one. If indicated, change antibiotics in response to swab.

For suspected critically colonised wounds a two-week anti-microbial dressing challenge without microbiological swabbing is appropriate.

Systemic antibiotics should be used in the presence of systemic and spreading infection.

Antibiotics should be prescribed in line with local antibiotic prescribing policies. A swab should also be sent, and antibiotic changed if indicated by result.

Anti-microbial dressings

Anti-microbial dressings should be considered to reduce bio burden in acute and chronic wounds that are infected or are being prevented from healing by microorganisms

The products available to combat infection and promote healing work in particular ways:

  • First is in wound bed preparation, this includes an accurate in-depth wound assessment:
    • Identify any underlying cause or contributory factor.
    • Recognise and deal with the tissue in the wound and of the surrounding skin and tissue.
    • Consider bacterial content and whether wound contaminated, colonised or clinically infected
    • Monitor the levels of exudate

Please see 17.3 Antimicrobial dressings

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If a wound is malodorous:

  • Remove necrotic material and excess slough
  • Exclude infection
  • Topical antibiotics should not be first choice
  • Consider use of activated charcoal product to combat malodour
  • Contact Tissue Viability nurse specialists before using any alternative therapies

Occlusion

Effective infection control interventions should include the minimising of contamination of wounds from pathogenic organisms. The use of dressings capable of providing a bacterial barrier should be encouraged particularly in the management of "at risk" patient groups. Semi-permeable films, hydrocolloids and foam dressings prevent the ingress of bacteria into the wound and help to prevent cross-infection to other individuals where wound contamination, colonisation and infection has occurred. Non-occlusive dressings must be changed as soon as strike-through has occurred.

The use of occlusive dressings on patients with diabetic/ischaemic foot ulceration is not recommended.

If transmission of bacterial burden, including MRSA, poses a risk to the patient or those in close contact, use a topical agent or dressing. A combination with systemic therapy maybe indicated. For further information see the Infection Control policy or contact a microbiologist.

  • Occluding wounds reduces the 02 tension within the wound and prevents contamination from outside bacteria. Bacteria do not have the opportunity to multiply.

Quorum sensing

  • Quorum sensing is the ability of the product to in effect 'drag' bacteria into the matrix of the dressing and thus remove it from the wound bed. The bacteria are attracted to the product and once ensconced are unable to leave. Quorum sensing is also the ability of a product to target specific organisms and render them indifferent in the wound bed.
  • The ability of these products depends not only on their mode of action but also on the ability of the dressing to keep the bacteria contained.

The decision to use a particular product should be based on

  • The suitability of the dressing to a particular patient scenario
  • The desired aim of treatment
  • Patient sensitivity / allergy
  • Availability
  • Agreed care plan with patient / carer
  • Cost consideration

Link between colonisation and the management of necrotic burden

The effective management of wounds relies on the preparation of an optimal wound healing environment. The presence of high levels of necrotic tissue in the wound presents an ideal environment for bacterial colonisation and proliferation. It also reduces the therapeutic effect of systemic antibiotic therapy. The effective treatment of wound infection and colonisation must include the management of the necrotic burden. Necrotic material can be removed from the wound by autolysis, enzymatic, sharp debridement or larval therapy, by a trained healthcare professional.

The choice of the most appropriate debridement method depends on individual patient circumstances, wound status, therapy availability, clinician expertise and the healthcare environment. Expert advice is available and should be sought.

Clinically clean versus aseptic dressing technique

The prevention of spreading wound contaminants from the environment to the patient, or between patients is everyone's responsibility. Good hand hygiene and adherence to infection control guidelines is essential.

The use of sterile dressing packs and aseptic dressing techniques is not essential for all types of dressing, see 17.7 Wound care accessories

Clinically clean procedures may be adopted to manage chronic, colonised wounds (such as the treatment of venous ulceration) or in the first aid of traumatic injuries.

Procedures vary within clinical environments. It is the responsibility of the healthcare practitioner to seek out, and adhere to, those protocols that are available.

A wound will not heal unless it is red and clean, and therefore it must be moist and warm with adequate supplies of nutrition and oxygen. Some patients experience delayed healing or develop chronic wounds and the cause of this may be either patient related (intrinsic) or wound-related (extrinsic).

Factors to consider in cases of deterioration or failure to heal

  • More than 10 days for a trauma
  • More than 4 weeks for a leg ulcer

If a leg ulcer fails to heal with conventional therapy within 12 weeks, specialist and/or vascular opinion should be sought.

Factors - Patient Factors

  • Nutrition: Good nutritional status is vital for effective healing to occur. Basal metabolic requirements are elevated during the healing process and therefore an increased intake of amino acids, carbohydrates and lipids, vitamins, minerals and trace elements is necessary
  • Blood supply: If blood supply is compromised, the resultant ischaemia and subsequent reperfusion leads to the production of free radicals, which can cause tissue injury. It is also essential that bandages / dressings are not applied so tightly to a wound that the circulation to the area is impaired. It is also vital that any dressing does not stick to the wound surface so that on removal any new blood vessels formed become damaged
  • Age: Wound healing proceeds more rapidly in younger patients. Most wounds in healthy elderly patients heal well, although concomitant disease or poor nutrition may delay healing
  • Concurrent disease: Conditions such as diabetes, anaemia, ischaemia, jaundice or malignancy will adversely affect wound healing. Underlying medical problems must be addressed to optimise healing
  • Pharmacological agents: Corticosteroids, cytotoxic drugs and prostaglandin inhibitors adversely affect the cell-mediated immune responses taking place during healing. Hydrogen peroxide and hypochlorites can have a detrimental effect on wound healing
  • Smoking: Contraction of wounds is impaired, oxygen tension in the tissues is reduced, and platelets are more prone to aggregate

Factors - Wound environment

  • Moisture / humidity: Healing is optimal in a moist wound environment, which facilitates more rapid angiogenesis and epithelialisation. Wounds that become too moist can develop a macerated edge, which impairs healing and may encourage bacterial and fungal infections leading to further tissue breakdown
  • Temperature: Wounds heal more rapidly if the local temperature is maintained around 37oc. In order to avoid a drop-in temperature, the number of dressing changes should be minimised and conducted as quickly as possible. Wounds should not remain uncovered awaiting assessment by the clinician
  • Oxygenation: Creation of a hypoxic environment may be appropriate when a wound needs to granulate, whereas a dressing more permeable to oxygen may be appropriate during epithelialisation.
  • pH: Closely related to the degree of oxygenation. Dressings of neutral pH are preferred.
  • Infection: As distinct from colonisation, is associated with delayed wound healing. Pressure ulcers and leg ulcers are usually colonised, and this does not require intervention. Thus, if there is no clinical evidence of clinical infection, wound swabs are not required. Occlusive dressings should be avoided if anaerobic infection is suspected, as this will facilitate the growth of dangerous anaerobes. Generally, dressings should prevent bacterial contamination of the wound. If spreading erythema, pain and/or pyrexia are present, medical advice should be sought
  • Particulate contamination / irritants: Clean wounds heal more quickly than contaminated, dirty wounds. Slough and debris should be removed from the wound as this inhibits healing and can increase the risk of infection. Specialist advice should be sought prior to removing non-viable tissue in patients with diabetes