title: Biofilm-forming Staphylococcus epidermidis expressing vancomycin resistance early after adhesion to a metal surface.
abstract: We investigated biofilm formation and time of vancomycin (VCM) resistance expression after adhesion to a metal surface in Staphylococcus epidermidis. Biofilm-forming Staphylococcus epidermidis with a VCM MIC of 1 μg/mL was used. The bacteria were made to adhere to a stainless steel washer and treated with VCM at different times and concentrations. VCM was administered 0, 2, 4, and 8 hours after adhesion. The amount of biofilm formed was evaluated based on the biofilm coverage rates (BCRs) before and after VCM administration, bacterial viability in biofilm was visually observed using the fluorescence staining method, and the viable bacterial count in biofilm was measured. The VCM concentration required to decrease BCR significantly compared with that of VCM-untreated bacteria was 4 μg/mL, even in the 0 hr group. In the 4 and 8 hr groups, VCM could not inhibit biofilm growth even at 1,024 μg/mL. In the 8 hr group, viable bacteria remained in biofilm at a count of 10(4) CFU even at a high VCM concentration (1,024 μg/mL). It was suggested that biofilm-forming Staphylococcus epidermidis expresses resistance to VCM early after adhesion to a metal surface. Resistance increased over time after adhesion as the biofilm formed, and strong resistance was expressed 4-8 hours after adhesion.
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Toshiyuki
authors: T
authors: Sakimura
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Shiro
authors: S
authors: Kajiyama
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Shinji
authors: S
authors: Adachi
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Ko
authors: K
authors: Chiba
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Akihiko
authors: A
authors: Yonekura
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Masato
authors: M
authors: Tomita
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Hironobu
authors: H
authors: Koseki
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Takashi
authors: T
authors: Miyamoto
authors: Department of Gross Anatomy, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Toshiyuki
authors: T
authors: Tsurumoto
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8501, Japan.
authors: Makoto
authors: M
authors: Osaki
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D015169:Colony Count, Microbial; D005453:Fluorescence; D008670:Metals / Q000494:pharmacology*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000502:physiology*; D013499:Surface Properties; D013997:Time Factors; D014640:Vancomycin / Q000494:pharmacology; D020713:Vancomycin Resistance / Q000187:drug effects
chemical_list: D008670:Metals; D014640:Vancomycin