title: Early implant-associated osteomyelitis results in a peri-implanted bacterial reservoir.
abstract: Implant-associated osteomyelitis (IAO) is a common complication in orthopedic surgery. The aim of this study was to elucidate how deep IAO can go into the peri-implanted bone tissue within a week. The study was performed in a porcine model of IAO. A small steel implant and either 104CFU/kg body weight of Staphylococcus aureus or saline was inserted into the right tibial bone of 12 pigs. The animals were consecutively killed on day 2, 4 and 6 following implantation. Bone tissue around the implant was histologically evaluated. Identification of S. aureus was performed immunohistochemically on tissue section and with scanning electron microscopy and peptide nucleic acid in situ hybridization on implants. The distance of the peri-implanted pathological bone area (PIBA), measured perpendicular to the implant, was significantly larger in infected animals compared to controls (p = 0.0014). The largest differences were seen after 4 and 6 days of inoculation, where PIBA measurements of up to 6 mm were observed. Positive S. aureus bacteria were identified on implants and from 25 μm to 6 mm into PIBA. This is important knowledge for optimizing outcomes of surgical debridement in osteomyelitis.
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Louise Kruse
authors.initials: LK
authors.lastname: Jensen
authors.affiliation: Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Janne
authors.initials: J
authors.lastname: Koch
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Bent
authors.initials: B
authors.lastname: Aalbaek
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Arshnee
authors.initials: A
authors.lastname: Moodley
authors.affiliation: Costerton Biofilm Center, Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bjarnsholt
authors.affiliation: Costerton Biofilm Center, Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Kasper Nørskov
authors.initials: KN
authors.lastname: Kragh
authors.affiliation: Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Petersen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Henrik Elvang
authors.initials: HE
authors.lastname: Jensen
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006651:Histocytochemistry; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008853:Microscopy; D010019:Osteomyelitis / Q000382:microbiology* / Q000473:pathology*; D016459:Prosthesis-Related Infections / Q000382:microbiology* / Q000473:pathology*; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000473:pathology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013552:Swine; D013977:Tibia / Q000473:pathology
keywords: 
  S. aureus
  ; Implant-associated osteomyelitis; animal experiment; histopathology