In-Vitro Assessment of Wound Dressing Bacterial Sequestration

Introduction:

Chronic wounds are highly susceptible to infection due to their prolonged healing rates and therefore increased durations of time without the skin infection barrier. Bioburden within a wound has been linked to healing outcome and it is therefore desirable to remove bacteria from the wound surface. A selection of foam dressings were tested for their ability to sequester bacteria through absorption and retention.

Method:

A dressing (A) was tested for bacterial location following absorption of an overnight culture of MRSA. The dressing was dissected into components, and processed in stomacher bags to remove the bacteria. Total viable cell counts were conducted to determine the bacterial concentration within each component.

Four dressings (A,B,C &D) were tested for bacteria release upon compression. 35ml of Pseudomonas Aeruginosa culture at 153x10⁶CFU/ml was applied to each dressing, allowed to absorb and then left for a further 2 minutes. Each dressing was then compressed by hand until no further fluid was able to be removed. The fluid was collected and weighed. Total viable cell counts were conducted to determine bacteria concentration within the eluted fluid. This was then used to determine how much bacteria had been released from each dressing on compression

Results:

Dressing A was shown to store 99.7% of MRSA absorbed within its highly retentive absorbent core and therefore away from the wound.

Dressing A eluted 0.07g of fluid at 136x10⁶CFU/ml.

Dressing B eluted 23.16g of fluid at 138x10⁶CFU/ml.

Dressing C eluted 14.57g of fluid at 172x10⁶CFU/ml.

Dressing D eluted 20.78g of fluid at 184x10⁶CFU/ml.

Conclusion:

Dressing A was shown to have the highest capability for retaining solutions containing bacteria and therefore storing bacteria away from a wound.