Use of Molecular Diagnostics Lab in the Wound Clinic

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Issue Number:  Volume 6 Issue 3 ­ April 2012 Author(s): Randall Wolcott, MD, CWS

Wound clinics are being assailed from many different directions in today’s healthcare environment to heal wounds more quickly. Third Party payers such as Medicare are now limiting the number of debridements and other services that can be provided to the patient, making it imperative to heal wounds efficiently. Also, for a wound treatment clinic to differentiate itself from the competitive pressure of other providers, wound healing outcomes must improve. To best serve each individual patient, wound healing should be as rapid as possible. Therefore, it is necessary for each wound treatment clinic to utilize the emerging technologies that will accomplish this goal.

Generally, wound care providers believe bacteria are an important reason why wounds don’t heal. More often than not (more than 68% of the time), we prescribe at least one course of antibiotics to a patient with a chronic wound.1 Such approaches work just enough of the time to keep us treating wounds with antibiotics and/or antimicrobial dressings. Plus, three of the top four wound dressings worldwide are antimicrobial. However, the literature does not support our actions. A recent Cochran analysis2 concludes there is no evidence to support the use of antibiotics for the treatment of venous leg ulcers, and the Infectious Disease Society of America guidelines for diabetic foot ulcers strongly discourage the general use of antibiotics, recommending only the most limited use of antibiotics when absolutely necessary. A literature review by Landis 3 found no evidence for the prophylactic or routine use of antibiotics when there are no signs of clinical infection or increased bacterial bioburden in chronic wounds.

Several studies1,4,5 show that, based on culture results, antibiotic use does not improve wound healing outcomes. Thus, objective data do not support clinicians' belief that microorganism management is crucial to wound healing. The issue may not be so much the limitation of the antibiotics or the dressings as the diagnostic tool we use to direct the use of these treatments. Wound care providers have long known that many wounds, especially diabetic foot ulcers, are polymicrobial.6

Only recently have we come to understand that wound microbial burden is usually organized as a biofilm on the surface of the wound.7 Biofilm in nature and in human chronic infections is generally polymicrobial and very resistant to antibiotics and its host immunity. 8 There is some concern that the minor species in an individual wound biofilm may just be contaminants and as such do not contribute to the virulence of the wound bioburden. However, until the science regarding the subject is better understood, it may be prudent not to ignore any of the constituents of the polymicrobial infection.9 Therefore, identifying all the different bacterial and fungal species of microorganisms that make up the wound biofilm, and securing accurate relative quantification of each species is important for today’s wound clinics. Because “time is tissue,” a test for microbial identification and quantification should be rapid. Any new diagnostic test also should be more accurate in identifying microbes than current clinical cultures.

The test should be sensitive enough to identify all different microorganisms regardless of their percentage of the whole community. The diagnostic test should be as free from bias (able to evaluate one group of bugs the same as another group of bugs) as possible. Plus, the microbial identification test must not break the bank.