title: A comparison of Staphylococcus aureus biofilm formation on cobalt-chrome and titanium-alloy spinal implants.
abstract: The use of cobalt chrome (CoCr) implants in spinal surgery has become increasingly popular. However, there have been no studies specifically comparing biofilm formation on CoCr with that of titanium-alloy spinal implants. The objective of this study was to compare the difference in propensity for biofilm formation between these two materials, as it specifically relates to spinal rods. Staphylococcus aureus subsp. Aureus (ATCC 6538) were incubated with two different types of spinal rods composed of either CoCr or titanium-alloy. The spinal rods were then subject to a trypsin wash to allow for isolation of the colonized organism and associated biofilms. The associated optical density values (OD) from the bacterial isolates were obtained and the bacterial solutions were plated on brain-heart infusion agar plates and the resultant colony-forming units (CFU) were counted. The OD values for the titanium-alloy rods were 1.105±0.096nm (mean±SD) and 1.040±0.026nm at 48hours and 96hours, respectively. In contrast, the OD values for the CoCr rods were 1.332±0.161nm and 1.115±0.207nm at 48 and 96hours, respectively (p<0.05). The CFU values were 1481±417/100mm(2) and 745±159/100mm(2) at 48 and 96hours, respectively for the titanium-alloy group. These values were significantly lower than the CFU values obtained from the CoCr group which were 2721±605/100mm(2) and 928±88/100mm(2) (p<0.001) at both 48 and 96hours respectively. Our findings, evaluating both the OD and CFU values, indicate that implants composed of CoCr had a higher proclivity towards biofilm formation compared to titanium-alloy implants.
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA.
authors.forename: Shalin S
authors.initials: SS
authors.lastname: Patel
authors.affiliation: Division of Microbiology and Molecular Genetics, Loma Linda University School of Medicine, Loma Linda, CA 92354, USA.
authors.forename: Wilson
authors.initials: W
authors.lastname: Aruni
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA.
authors.forename: Serkan
authors.initials: S
authors.lastname: Inceoglu
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA.
authors.forename: Yusuf T
authors.initials: YT
authors.lastname: Akpolat
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Botimer
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA.
authors.forename: Wayne K
authors.initials: WK
authors.lastname: Cheng
authors.affiliation: Department of Orthopedic Surgery, Loma Linda University Medical Center, 11406 Loma Linda Drive, Suite 218, Loma Linda, CA 92354, USA. Electronic address: Odanisa@yahoo.com.
authors.forename: Olumide A
authors.initials: OA
authors.lastname: Danisa
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002858:Chromium Alloys; D006801:Humans; D019637:Orthopedic Procedures / Q000295:instrumentation; D019736:Prostheses and Implants / Q000382:microbiology*; D016459:Prosthesis-Related Infections / Q000382:microbiology*; D013131:Spine / Q000601:surgery; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000502:physiology*; D014025:Titanium
chemical_list: D002858:Chromium Alloys; D014025:Titanium
keywords: Biofilm; Cobalt chrome; Spinal implant; Staphylococcus aureus; Titanium alloy