title: Bad to the Bone: On In Vitro and Ex Vivo Microbial Biofilm Ability to Directly Destroy Colonized Bone Surfaces without Participation of Host Immunity or Osteoclastogenesis.
abstract: Bone infections are a significant public health burden associated with morbidity and mortality in patients. Microbial biofilm pathogens are the causative agents in chronic osteomyelitis. Research on the pathogenesis of osteomyelitis has focused on indirect bone destruction by host immune cells and cytokines secondary to microbial insult. Direct bone resorption by biofilm pathogens has not yet been seriously considered. In this study, common osteomyelitis pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Streptococcus mutans) were grown as biofilms in multiple in vitro and ex vivo experiments to analyze quantitative and qualitative aspects of bone destruction during infection. Pathogens were grown as single or mixed species biofilms on the following substrates: hydroxyapatite, rat jawbone, or polystyrene wells, and in various media. Biofilm growth was evaluated by scanning electron microscopy and pH levels were monitored over time. Histomorphologic and quantitative effects of biofilms on tested substrates were analyzed by microcomputed tomography and quantitative cultures. All tested biofilms demonstrated significant damage to bone. Scanning electron microscopy indicated that all strains formed mature biofilms within 7 days on all substrate surfaces regardless of media. Experimental conditions impacted pH levels, although this had no impact on biofilm growth or bone destruction. Presence of biofilm led to bone dissolution with a decrease of total volume by 20.17±2.93% upon microcomputed tomography analysis, which was statistically significant as compared to controls (p <0.05, ANOVA). Quantitative cultures indicated that media and substrate did not impact biofilm formation (Kruskall-Wallis test, post-hoc Dunne's test; p <0.05). Overall, these results indicate that biofilms associated with osteomyelitis have the ability to directly resorb bone. These findings should lead to a more complete understanding of the etiopathogenesis of osteomyelitis, where direct bone resorption by biofilm is considered in addition to the well-known osteoclastic and host cell destruction of bone.
authors.affiliation: Department of Pharmaceutical Microbiology and Parasitology, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Junka
authors.affiliation: Center for Advanced Manufacturing Technologies (CAMT/FPC), Faculty of Mechanical Engineering, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Szymczyk
authors.affiliation: Center for Advanced Manufacturing Technologies (CAMT/FPC), Faculty of Mechanical Engineering, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Ziółkowski
authors.affiliation: Division of Infectious Diseases of Animals and Veterinary Administration, Wroclaw University, Wroclaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Karuga-Kuzniewska
authors.affiliation: Department of Pharmaceutical Microbiology and Parasitology, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Smutnicka
authors.affiliation: Department of Clinical Chemistry, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Bil-Lula
authors.affiliation: Department of Pharmaceutical Microbiology and Parasitology, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Marzenna
authors.initials: M
authors.lastname: Bartoszewicz
authors.affiliation: Center for Biofilms and Craniofacial Molecular Biology, Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America.
authors.forename: Susan
authors.initials: S
authors.lastname: Mahabady
authors.affiliation: Center for Biofilms and Craniofacial Molecular Biology, Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America.
authors.forename: Parish Paymon
authors.initials: PP
authors.lastname: Sedghizadeh
mesh_terms: D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D017886:Durapatite / Q000494:pharmacology; D007568:Jaw / Q000382:microbiology* / Q000473:pathology; D008297:Male; D010006:Osteoblasts / Q000382:microbiology* / Q000648:ultrastructure; D010019:Osteomyelitis / Q000382:microbiology*; D011137:Polystyrenes / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology
chemical_list: D011137:Polystyrenes; D017886:Durapatite