title: Immunoproteomic Identification of In Vivo-Produced Propionibacterium acnes Proteins in a Rabbit Biofilm Infection Model.
abstract: Propionibacterium acnes is well-known as a human skin commensal but can also act as an invasive pathogen causing implant-associated infections. In order to resolve these types of P. acnes infections, the implants must be removed, due to the presence of an established biofilm that is recalcitrant to antibiotic therapy. In order to identify those P. acnes proteins produced in vivo during a biofilm infection, we established a rabbit model of implant-associated infection with this pathogen. P. acnes biofilms were anaerobically grown on dextran beads that were then inoculated into the left tibias of rabbits. At 4 weeks postinoculation, P. acnes infection was confirmed by radiograph, histology, culture, and PCR. In vivo-produced and immunogenic P. acnes proteins were detected on Western blot using serum samples from rabbits infected with P. acnes after these bacterial proteins were separated by two-dimensional gel electrophoresis. Those proteins that bound host antibodies were then isolated and identified by tandem mass spectrometry. Radiographs and histology demonstrated a disruption in the normal bone architecture and adherent biofilm communities in those animals with confirmed infections. A total of 24 immunogenic proteins were identified; 13 of these proteins were upregulated in both planktonic and biofilm modes, including an ABC transporter protein. We successfully adapted a rabbit model of implant-associated infection for P. acnes to identify P. acnes proteins produced during a chronic biofilm-mediated infection. Further studies are needed to evaluate the potential of these proteins for either a diagnostic test or a vaccine to prevent biofilm infections caused by P. acnes.
authors.affiliation: Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Baltimore, Maryland, USA Department of Infectious Diseases and Hospital Epidemiology, University of Zurich, Zurich, Switzerland.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Achermann
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: Bao
authors.initials: B
authors.lastname: Tran
authors.affiliation: Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: Misun
authors.initials: M
authors.lastname: Kang
authors.affiliation: Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: Janette M
authors.initials: JM
authors.lastname: Harro
authors.affiliation: Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Baltimore, Maryland, USA Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Baltimore, Maryland, USA mshirtliff@umaryland.edu.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Shirtliff
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D018441:Biofilms / Q000254:growth & development; D004195:Disease Models, Animal; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D020007:Implants, Experimental / Q000382:microbiology; D010019:Osteomyelitis / Q000000981:diagnostic imaging / Q000382:microbiology; D011425:Propionibacterium acnes / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D016459:Prosthesis-Related Infections / Q000382:microbiology*; D040901:Proteomics; D011817:Rabbits; D011859:Radiography; D053719:Tandem Mass Spectrometry; D013977:Tibia / Q000000981:diagnostic imaging / Q000382:microbiology; D015854:Up-Regulation
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins