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Identify and Treat the Cause: 4.6 Presence of Superficial Bacteria

Surgical Wound Infection

Level A, B and C: RNAO’s Interpretation of Evidence1

Surgical wounds, like most wounds, can become infected with superficial or spreading bacteria. The validated mnemonics ‘NERDS’ and ‘STONEES’ classify the signs and symptoms of localized infection (NERDS) and spreading infection (STONEES).

Presence of Superficial Bacteria

  • N - Non-healing wound
  • E - Exudate increased
  • R - Red friable (fragile tissue that bleeds easily)
  • D - Debris (presence of necrotic tissue (eschar/slough)) in wound
  • S - Smell

Presence of Spreading Bacteria (< 3 low bacteria count, >3 high bacteria count)

  • S - Size increasing
  • T - Temperature increased ( >3 degrees F difference)
  • O - Os (probes to bone or bone is increased)
  • N - New areas of breakdown
  • E - Exudate present
  • E - Erythema and/or Edema
  • S - Smell

In addition to recognizing the signs and symptoms of infection in surgical wounds, it may be helpful to obtain a culture and sensitivity (C&S) using a validated method of sampling to quantify bacteria in wounds. Tissue biopsies are considered the gold standard but unfortunately are not practical in many settings. Fortunately, a linear relationship between quantitative tissue biopsy and swab for C&S taken using the Levine method of sampling (see below) has been validated and is recommended for assessing any open wound. Swabs for C&S are important in determining the type of bacteria and the appropriate antibiotics, but are not necessary to confirm the presence or absence of infection. The C&S results may not reflect the presence or absence of biofilm.

Obtain a swab for C&S when:2
  • Clinically serious infection
  • Patients are hypersensitive to 1st line of antibiotics
  • Antibiotic-resistant pathogens suspected (recent hospitalization or out of country travel)
Levine Method for obtaining C&S laboratory swab:3
  • Cleanse wound thoroughly
  • Place swab on granulation tissue (must be granulation tissue only –if none present, tissue aspiration or biopsy may be required)
  • Apply enough pressure to extract fluid
  • Turn swab 360 degrees on fluid (avoid slough or debris)
  • Place swab in transport medium

Provide Local Wound Care  
  1. Ontario, Registered Nurses Association of. Assessment and Management of Venous Leg Ulcers. Toronto : s.n., 2004.
  2. Excellence, National Institute for Health and Clinical. Surgical Site Infection - Prevention and treatment of surgical site infection. London, U.K. : Royal College of Obstetricians and Gynaecologists, 2008.
  3. Increased bacterial burden and infection: The Story of NERDS and STONEES. Sibbald R G, Woo K, Ayello E. 8, s.l. : Advanced Skin and Wound Care, 2006, Vol. 19.

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