[Effect of enzybiotics on the healing of Staphylococcus aureus-infected skin wounds in a pig model].

Abstract

Introduction: Staphylococcus aureus is a gram-positive, facultatively anaerobic coccus capable of causing infectious diseases in animals and humans. Especially dangerous are multidrug-resistant forms with poor or even no response to available treatments.

Objectives: The study aimed to verify the effect of enzybiotics on the healing of S. aureus-infected skin wounds in an experimental pig model.

Methodology: Two pigs were included in the experiment and wounds (10/pig) of 5 × 5 cm in size with 2 cm spacing were made by incision on their backs. The wounds were infected with a methicillin (oxacillin) and amoxicillin-resistant strain of S. aureus (MRSA). The experimental groups consisted of individual wounds that were infected with one sequence type of S. aureus at a concentration of 2 × 109 CFU/mL. Two wounds were left untreated (N), four wounds were using hydrogel with added lysostaphin, and four wounds were treated using hydrogel with added lysostaphin and endolysin. Subsequently, samples were taken from each wound on days 4, 7, 11, and 14. The material was processed using a standard histological technique of paraffin blocks and the sections were stained with hematoxylineosin.

Results: The results show that these defects present a full spectrum of reparative changes with re-epithelialization with alternating sections of necrosis and newly formed granulation tissue with an accompanying round cell inflammatory infiltrate in edematous tissue and surface scabs. On the surface of the wounds and also in smaller groups in the newly formed granulation tissue, coccoid formations corresponding to S. aureus are visible. Compared to untreated wounds, hydrogel dressings with added lysostaphin or lysostaphin and endolysin trapped greater numbers of S. aureus cocci colonies, which subsequently died off to a large extent.

Conclusion: Enzybiotics may have interesting potential in the topical therapy of MRSA-infected skin wounds.