title: Inflammatory and antimicrobial responses to methicillin-resistant Staphylococcus aureus in an in vitro wound infection model.
abstract: Treatment of patients with burn wound infections may become complicated by the presence of antibiotic resistant bacteria and biofilms. Herein, we demonstrate an in vitro thermal wound infection model using human skin equivalents (HSE) and biofilm-forming methicillin-resistant Staphylococcus aureus (MRSA) for the testing of agents to combat such infections. Application of a liquid nitrogen-cooled metal device on HSE produced reproducible wounds characterized by keratinocyte death, detachment of the epidermal layer from the dermis, and re-epithelialization. Thermal wounding was accompanied by up-regulation of markers for keratinocyte activation, inflammation, and antimicrobial responses. Exposure of thermal wounded HSEs to MRSA resulted in significant numbers of adherent MRSA/HSE after 1 hour, and multiplication of these bacteria over 24-48 hours. Exposure to MRSA enhanced expression of inflammatory mediators such as TLR2 (but not TLR3), IL-6 and IL-8, and antimicrobial proteins human β-defensin-2, -3 and RNAse7 by thermal wounded as compared to control HSEs. Moreover, locally applied mupirocin effectively reduced MRSA counts on (thermal wounded) HSEs by more than 99.9% within 24 hours. Together, these data indicate that this thermal wound infection model is a promising tool to study the initial phase of wound colonization and infection, and to assess local effects of candidate antimicrobial agents.
authors: Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands ; Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Elisabeth M
authors: EM
authors: Haisma
authors: Marion H
authors: MH
authors: Rietveld
authors: Anna
authors: A
authors: de Breij
authors: Jaap T
authors: JT
authors: van Dissel
authors: Abdoelwaheb
authors: A
authors: El Ghalbzouri
authors: Peter H
authors: PH
authors: Nibbering
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D018441:Biofilms; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000166:cytology; D005786:Gene Expression Regulation; D006358:Hot Temperature; D006801:Humans; D007249:Inflammation / Q000473:pathology*; D053582:Interleukin-1alpha / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008954:Models, Biological; D016712:Mupirocin / Q000008:administration & dosage; D051381:Rats; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology*; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051196:Toll-Like Receptor 3 / Q000378:metabolism; D014946:Wound Infection / Q000188:drug therapy* / Q000382:microbiology*
chemical_list: D000890:Anti-Infective Agents; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; C495342:TLR2 protein, human; C495344:TLR3 protein, human; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D003094:Collagen; D016712:Mupirocin