132 Can a Topical Antimicrobial Agent Penetrate a Bi-Layered Cell Therapy and be Effective Against Methicillin-Resistant Staphylococcus Aureus?

Abstract

Background: Bilayered cell therapy (BLCT) is a significant advancement in the field of wound healing. BLCT expresses multiple growth factors found in normal skin, and provides a biologically active matrix in chronic wounds. Antibiotic-resistant bacterium continues to be a major problem in chronic wounds. The use of appropriate topical antimicrobial agents could be one of the first steps in prevention of wound infection, although their use with BLCT is limited due to reported toxicity to cultured keratinocytes. Objectives: This study was designed to see whether a topical antimicrobial agent is able to permeate through the BLCT and inhibits the growth of Methicillin-Resistant Staphylococcus Aureus (MRSA). Mupirocin was used because of its lack of toxicity to cultured keratinocytes. Methods: MRSA (ATCC# 33591) strain was used for these studies. The entire surface of blood agar plates were covered with a high inoclum of MRSA. BLCT specimens were placed on the agar plates and mupirocin was then applied on the top surface. As a positive control, mupirocin was applied directly on the agar plate, while BLCT specimens alone were used as negative control. The plates were subsequently incubated for 24 hours after which the zones of inhibition were assessed. Results: Placing mupirocin on top of BLCT gave a 41.9 ± 17.2 mm inhibition zone diameter. Although it was smaller than the inhibition zone diameter produced by direct administration of mupirocin (26.3 ± 9.4 mm), this difference was not statistically significant. BLCT by itself did not create a zone of inhibition. Conclusion: Mupirocin is able to permeate BLCT and inhibit the bacterial growth underneath it. This study may have important clinical implications.