title: A new animal model for implant-related infected non-unions after intramedullary fixation of the tibia in rats with fluorescent in situ hybridization of bacteria in bone infection.
abstract: There is no adequate animal model to mimic the difficult clinical situation of infected non-union of the tibia after intramedullary stabilization. The purpose was to establish an animal model of implant-related infected non-unions of the tibia in rats. Furthermore, it was evaluated if detection of bacteria by fluorescent in situ hybridisation (FISH) technique is possible in bone infection. 17 rats were used in which osteotomy of the midshaft tibia was performed and stabilized with an intramedullary device. Two groups were tested: group 1: contamination of the osteotomy site with 10(4) colony forming units (CFUs) of Staphylococcus aureus (11 animals), group 2: no bacterial contamination (6 animals). The animals were sacrificed after 42 days and bone healing and infection were assessed clinically, by X-ray, micro-CT, and microbiological methods including FISH technique using EUB and STAPHY probes. Histology and scanning electron microscopy (SEM) for biofilm formation were performed. All animals of the control group showed uneventful bone healing after 6 weeks without any signs of local infections. 10 of 11 (90.9%) animals of group 1 with bacterial contamination exhibited infected non-union formation with positive clinical, radiological and microbiological infection signs of the tibia but without any systemic infection signs. FISH technique was able to identify bacteria in the infected bone. All intramedullary implants from the infected animals showed positive biofilm formation in SEM. This work presents the first animal model for the induction of intramedullary device-related infected non-union in the tibia and detection of bacteria by FISH technique in infected bone.
authors.affiliation: Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Giessen, Germany. volker.alt@chiru.med.uni-giessen.de
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Lips
authors.forename: Christoph
authors.initials: C
authors.lastname: Henkenbehrens
authors.forename: Dominik
authors.initials: D
authors.lastname: Muhrer
authors.forename: Márcia Cristina
authors.initials: MC
authors.lastname: Oliveira Cavalcanti
authors.forename: Marcia
authors.initials: M
authors.lastname: Cavalcanti-Garcia
authors.forename: Ursula
authors.initials: U
authors.lastname: Sommer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thormann
authors.forename: Gabor
authors.initials: G
authors.lastname: Szalay
authors.forename: Christian
authors.initials: C
authors.lastname: Heiss
authors.forename: Theodoros
authors.initials: T
authors.lastname: Pavlidis
authors.forename: Eugen
authors.initials: E
authors.lastname: Domann
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
mesh_terms: D000818:Animals; D018441:Biofilms; D001850:Bone Diseases, Infectious / Q000150:complications / Q000000981:diagnostic imaging / Q000382:microbiology* / Q000473:pathology; D004195:Disease Models, Animal; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects*; D005599:Fractures, Ununited / Q000150:complications* / Q000000981:diagnostic imaging / Q000382:microbiology / Q000473:pathology; D017404:In Situ Hybridization, Fluorescence; D016459:Prosthesis-Related Infections / Q000150:complications* / Q000000981:diagnostic imaging / Q000382:microbiology / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013211:Staphylococcus aureus / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D013978:Tibial Fractures / Q000150:complications* / Q000000981:diagnostic imaging / Q000382:microbiology / Q000473:pathology; D055114:X-Ray Microtomography; D014965:X-Rays