title: Impact of prophylactic CpG Oligodeoxynucleotide application on implant-associated Staphylococcus aureus bone infection.
abstract: TLR-9 ligand CpG oligodeoxynucleotide type B (CpG ODN) induces a proinflammatory environment. We evaluated the effects of a preoperative CpG ODN application in an implant-associated Staphylococcus aureus bone infection model by monitoring bacterial loads and cytokine and chemokine levels. A total of 95 rats were used in four different groups: CpG ODN group (group 1; n=25), non-CpG-ODN group (group 2; n=25); saline pretreatment (group 3; n=25), and one uninfected group (group 4; n=20). A single dose of CpG-ODN was administered to the left tibialis anterior muscle 3days prior to surgery and the tibia midshaft was osteotomized, stabilized by an intramedullary implant and subsequently contaminated with 10(3) colony forming units (CFUs) of S. aureus in groups 1-3. The osteotomy gap in animals of group 4 was not contaminated with S. aureus and those animals did not receive any pretreatment. CpG ODN administration resulted in significant reduction of the bacterial load in tibia tissue homogenate and on the implant surface on day 1 post-infection compared to non-CpG-ODN pretreatment (p<0.05; p<0.05). Reductions in bacterial CFUs, compared to non-treated (saline) controls, were approximately 67% and 77% for bone tissue homogenates and implants. No bacteria were detected in uninfected rats. Early reduction of bacterial CFUs in the tibia was accompanied by increased levels of proinflammatory mediators MIP-2, IL-1β and RANTES in bone tissue milieu of the CpG ODN treated group compared to controls. At day 42 post-infection, bone marrow tissue of rats pretreated with CpG ODN had comparable high bacterial CFU numbers as the non-CpG ODN or saline treated groups. Microbiological analysis of implants removed from CpG ODN treated rats showed high bacterial growth densities on their surfaces which were not different from those observed in controls. In histology, all animals of groups 1-3 showed established infected non-unions. Additionally, inflammatory mediator profiles in bone marrow homogenates of CpG ODN treated rats resembled those seen in infected controls. In this rat model, prophylactic administration of a single dose of CpG ODN, resulted in marked reduction of S. aureus load in the infected tibia during the initial stage of infection but failed to prevent development of chronic infection over time.
authors.affiliation: Institute of Medical Microbiology, Justus-Liebig-University Giessen, 35392 Giessen, Germany. Electronic address: shneh.sethi@gmx.de.
authors.forename: Shneh
authors.initials: S
authors.lastname: Sethi
authors.affiliation: Department of Trauma Surgery Giessen, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thormann
authors.affiliation: Laboratory of Experimental Trauma Surgery, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Sommer
authors.affiliation: Laboratory of Experimental Trauma Surgery, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Stötzel
authors.affiliation: Laboratory of Experimental Trauma Surgery, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Walid
authors.initials: W
authors.lastname: Mohamed
authors.affiliation: Department of Trauma Surgery Giessen, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
authors.affiliation: Institute of Medical Microbiology, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Eugen
authors.initials: E
authors.lastname: Domann
authors.affiliation: Institute of Medical Microbiology, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Trinad
authors.initials: T
authors.lastname: Chakraborty
authors.affiliation: Department of Trauma Surgery Giessen, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
mesh_terms: D000818:Animals; D001847:Bone Diseases / Q000382:microbiology*; D018946:Chemokine CCL5 / Q000378:metabolism; D054426:Chemokine CXCL2 / Q000378:metabolism; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D053583:Interleukin-1beta / Q000378:metabolism; D008024:Ligands; D008297:Male; D009838:Oligodeoxyribonucleotides / Q000627:therapeutic use*; D019736:Prostheses and Implants / Q000009:adverse effects; D016459:Prosthesis-Related Infections / Q000188:drug therapy / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000517:prevention & control*; D013211:Staphylococcus aureus; D013977:Tibia / Q000382:microbiology / Q000473:pathology; D051217:Toll-Like Receptor 9 / Q000235:genetics
chemical_list: C408982:CPG-oligonucleotide; D018946:Chemokine CCL5; D054426:Chemokine CXCL2; D018925:Chemokines; C513296:Cxcl2 protein, rat; D016207:Cytokines; C000594089:IL1B protein, rat; D053583:Interleukin-1beta; D008024:Ligands; D009838:Oligodeoxyribonucleotides; C489640:Tlr9 protein, rat; D051217:Toll-Like Receptor 9
keywords: Chronic bone infection; CpG-ODN; Cytokines; Implants; Staphylococcus aureus