title: Efficacy of titanium dioxide photocatalyst for inhibition of bacterial colonization on percutaneous implants.
abstract: The purpose of this study was to evaluate the efficacy of titanium dioxide photocatalyst in inhibition of bacterial colonization on percutaneous implants. Titanium dioxide photocatalyst was prepared by direct oxidization of pure titanium substrate, and a comparative study with pure titanium was performed. The bactericidal ability of the photocatalyst was examined using methicillin-resistant Staphylococcus aureus (MRSA) suspensions in a colony-forming assay according to the Japanese Industrial Standards committee standard. After exposing the MRSA suspension on sample plates to ultraviolet A (UVA) light, the number of surviving bacteria was estimated. Next, an animal model for inhibition of colonization was examined in vivo. Pins were inserted into the femurs of rabbits, were infected with 10(8) colony-forming units of MRSA suspension, and were illuminated with UVA light for 60 min daily; the number of colonizing bacteria was estimated after 7 days. The bactericidal ability of the photocatalyst was apparent after 60 min, when the bacteria had almost disappeared. The number of colonizing bacteria on photocatalytic pins was decreased significantly in vivo. The photocatalyst was effective even against resistant bacterial colonization. Clinically, the incidence of percutaneous implant infection such as pin tract infection in external fixation could be reduced using the titanium photocatalyst.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine,Kyoto 602-8566, Japan. y-oka@koto.kpu-m.ac.jp
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Oka
authors.forename: Wook-Cheol
authors.initials: WC
authors.lastname: Kim
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Toshiko
authors.initials: T
authors.lastname: Hirashima
authors.forename: Hisashi
authors.initials: H
authors.lastname: Mouri
authors.forename: Hidenori
authors.initials: H
authors.lastname: Urade
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Itoh
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D001858:Bone Nails / Q000382:microbiology*; D002384:Catalysis; D020007:Implants, Experimental / Q000382:microbiology*; D010777:Photochemistry; D011817:Rabbits; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D014466:Ultraviolet Rays
chemical_list: C009495:titanium dioxide; D014025:Titanium