title: Efficacy of (99m)Tc-Labeled Ceftizoxime in the Diagnosis of Subclinical Infections Associated with Titanium Implants in Rats.
abstract: BACKGROUND
  Metal implants are used frequently in orthopedic procedures and the occurrence of subclinical low-virulence infection is difficult to diagnose. The objective of this study was to examine the hypothesis that peri-prosthetic subclinical infections may be diagnosed effectively in a murine model system using scintigraphic imaging with (99m)Tc-labeled ceftizoxime.
  
  
  METHODS
  A sample population of 3-mo old Wistar rats (mean weight 327 g) was divided randomly into a control group (n=6), which received sterile implants, and an experimental group (n=6), which received implants contaminated with Staphylococcus aureus strain ATCC6538-P. Animals were anesthetized and femoral titanium implants were fixed beneath muscle tissue in left hind limbs. Three weeks after surgery, animals were injected with (99m)Tc-ceftizoxime solution (62.9 MBq) and scintigraphic images were obtained at 3.5 and 6.5 h after tracer injection.
  
  
  RESULTS
  According to the scintigraphic images, the radiopharmaceutical showed affinity for the operated thigh areas of experimental animals but not for those of the control group. There was no difference between the control and experimental groups regarding the amount of radioactivity in the regions of interest measured at 3.5 h after injection of radiolabeled antibiotic, but the between-group difference determined at 6.5 h after treatment was statistically significant (p=0.026). Moreover, the level of radioactivity recorded in resected thigh tissues derived from experimental animals was greater than that of the control group (p=0.035).
  
  
  CONCLUSIONS
  (99m)Tc-ceftizoxime scintigraphy can localize preferentially periprosthetic-infected areas adjacent to metal implants in a murine model. Furthermore, the radiolabeled antibiotic appears to be capable of detecting alterations in the micro-environment close to the implant and of reaching the bacteria attached to the implant surface.
authors.affiliation: 1Departamento do Aparelho Locomotor, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Luiz Eduardo Moreira
authors.initials: LE
authors.lastname: Teixeira
authors.affiliation: 2Serviço de Ortopedia e Traumatologia, Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Guilherme Gontijo
authors.initials: GG
authors.lastname: Soares
authors.affiliation: 2Serviço de Ortopedia e Traumatologia, Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Henrique Cembranelli
authors.initials: HC
authors.lastname: Teixeira
authors.affiliation: 3Departamento de Radioisótopos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Isabella Kuniko Tavares Magalhães
authors.initials: IK
authors.lastname: Takenaka
authors.affiliation: 3Departamento de Radioisótopos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Simone Odília Fernandes
authors.initials: SO
authors.lastname: Diniz
authors.affiliation: 1Departamento do Aparelho Locomotor, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Marco Antônio Percope
authors.initials: MA
authors.lastname: de Andrade
authors.affiliation: 3Departamento de Radioisótopos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Valbert Nascimento
authors.initials: VN
authors.lastname: Cardoso
authors.affiliation: 4Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Ivana Duval
authors.initials: ID
authors.lastname: de Araújo
mesh_terms: D000818:Animals; D058345:Asymptomatic Infections; D015296:Ceftizoxime / Q000008:administration & dosage*; D004195:Disease Models, Animal; D007553:Isotope Labeling / Q000379:methods*; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D019919:Prosthesis Implantation / Q000009:adverse effects*; D011877:Radionuclide Imaging / Q000379:methods*; D017208:Rats, Wistar; D013530:Surgical Wound Infection / Q000175:diagnosis*; D014025:Titanium
chemical_list: D015609:Organotechnetium Compounds; D015296:Ceftizoxime; D014025:Titanium