Role of daptomycin on wound healing in a MRSA burn infected animal model [PublishAheadOfPrint]

Prolonged hospitalization and antibiotic therapy are risk factors for the development of methicillin-resistant S. aureus (MRSA) infections in thermal burn patients. We used a rat model to study the in vivo efficacy of daptomycin in the treatment of burn wound infections by S. aureus and we evaluated the wound healing process through morphological and immunohistochemical analysis. A copper bar heated in boiling water was applied on paraspinal site of each rat resulting in two full thickness burns. A small gauze was placed over each burn and inoculated with 5x10⁷ cfu of S. aureus ATCC 43300. The study included two control not infected groups, with and without daptomycin treatment, a control infected group that did not receive any treatment and two infected groups treated, respectively, with intraperitoneal daptomycin and teicoplanin. The main outcome measures were quantitative culture, histological evaluation of tissue repair and immunohistochemical expression of wound healing markers: Epidermal Growth Factor Receptor (EGFR) and Fibroblast Growth Factor 2 (FGF-2). The highest inhibition of infection was achieved in the group that received daptomycin reducing the bacterial load from 10⁷ cfu/mL to about 10³ cfu/g (P<0.01). The groups treated with daptomycin showed better overall healing with epithelialization and significantly higher collagen scores than the other groups, also confirmed by immunohistochemical data.

In conclusion, our results support the hypothesis that daptomycin, is an important modulator of wound repair by, possibly, reducing hypertrophic burn scar formation.

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