title: Microbial biofilms are able to destroy hydroxyapatite in the absence of host immunity in vitro.
abstract: OBJECTIVE
  It is widely thought that inflammation and osteoclastogenesis result in hydroxyapatite (HA) resorption and sequestrum formation during osseous infections, and microbial biofilm pathogens induce the inflammatory destruction of HA. We hypothesized that biofilms associated with infectious bone disease can directly resorb HA in the absence of host inflammation or osteoclastogenesis. Therefore we developed an in vitro model to test this hypothesis.
  
  
  METHODS
  Customized HA discs were manufactured as a substrate for growing clinically relevant biofilm pathogens. Single-species biofilms of Streptococcus mutans, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans and mixed-species biofilms of C albicans plus S mutans were incubated on HA discs for 72 hours to grow mature biofilms. Three different non-biofilm control groups also were established for testing. HA discs were then evaluated by means of scanning electron microscopy, micro-computed tomography metrotomography, x-ray spectroscopy, and confocal microscopy with planimetric analysis. In addition, quantitative cultures and pH assessment were performed. Analysis of variance was used to test for significance between treatment and control groups.
  
  
  RESULTS
  All investigated biofilms were able to cause significant (P < .05) and morphologically characteristic alterations in HA structure as compared with controls. The highest number of alterations observed was caused by mixed biofilms of C albicans plus S mutans. S mutans biofilm incubated in medium with additional sucrose content was the most detrimental to HA surfaces among single-species biofilms.
  
  
  CONCLUSIONS
  Our findings suggest that direct microbial resorption of bone is possible in addition to immune-mediated destruction, which has important translational implications for the pathogenesis of chronic bone infections and for targeted antimicrobial therapeutics.
authors.affiliation: Researcher, Department of Pharmaceutical Microbiology and Parasitology, Medical University of Wroclaw, Wrocław, Poland. Electronic address: feliks.junka@gmail.com.
authors.forename: Adam Feliks
authors.initials: AF
authors.lastname: Junka
authors.affiliation: Researcher, Centre for Advanced Manufacturing Technologies, Wroclaw University of Technology, Wrocław, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Szymczyk
authors.affiliation: Researcher, Department of Pharmaceutical Microbiology and Parasitology, Medical University of Wroclaw, Wrocław, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Smutnicka
authors.affiliation: Resident, Department of Maxillofacial and Plastic Surgery, Klinikum Oldenburg, Oldenburg, Germany.
authors.forename: Marcin
authors.initials: M
authors.lastname: Kos
authors.affiliation: Researcher, Centre for Advanced Manufacturing Technologies, Wroclaw University of Technology, Wrocław, Poland.
authors.forename: Iryna
authors.initials: I
authors.lastname: Smolina
authors.affiliation: Department Head, Department of Pharmaceutical Microbiology and Parasitology, Medical University of Wroclaw, Wrocław, Poland.
authors.forename: Marzenna
authors.initials: M
authors.lastname: Bartoszewicz
authors.affiliation: Department Head, Centre for Advanced Manufacturing Technologies, Wroclaw University of Technology, Wrocław, Poland.
authors.forename: Edward
authors.initials: E
authors.lastname: Chlebus
authors.affiliation: Researcher, Department of Pharmaceutical Microbiology and Parasitology, Medical University of Wroclaw, Wrocław, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Turniak
authors.affiliation: Department Head, Ostrow School of Dentistry and Center for Biofilms, University of Southern California, Los Angeles, CA.
authors.forename: Parish P
authors.initials: PP
authors.lastname: Sedghizadeh
mesh_terms: D058491:Bacterial Load; D001431:Bacteriological Techniques; D018441:Biofilms / Q000254:growth & development; D002176:Candida albicans / Q000254:growth & development / Q000378:metabolism; D018920:Coculture Techniques; D015169:Colony Count, Microbial; D003470:Culture Media; D003773:Dental Plaque / Q000378:metabolism / Q000382:microbiology; D017886:Durapatite / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009172:Mycology / Q000379:methods; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission; D013211:Staphylococcus aureus / Q000254:growth & development / Q000378:metabolism; D013295:Streptococcus mutans / Q000254:growth & development / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014054:Tomography; D055114:X-Ray Microtomography
chemical_list: D003470:Culture Media; D013395:Sucrose; D017886:Durapatite