title: Evaluation of 99mTc-UBI 29-41 scintigraphy for specific detection of experimental Staphylococcus aureus prosthetic joint infections.
abstract: OBJECTIVE
  (99m)Tc-UBI 29-41 (UBI), an antimicrobial peptide, specifically targets bacteria. We tested the ability of UBI to discriminate between infected and uninfected prosthetic joints using a rabbit model previously validated.
  
  
  METHODS
  Left knee arthroplasty was performed on 20 New Zealand rabbits, then 10(7) cfu of S. aureus (n = 12) or sterile saline (n = 8) was injected into the joint. On days 9 and 20 after surgery, planar UBI scintigraphy was performed in six infected and four uninfected rabbits, 1 h and 4 h p.i. (150 MBq), on a gamma camera. Operated-to-normal knee activity ratio (ONKR) was calculated on each scintigram. Then, after sacrifice, tissue samples of both knees were counted in a gamma counter.
  
  
  RESULTS
  One rabbit injected with sterile saline had cutaneous infection at sacrifice and was excluded from analysis. ONKR was higher in infected than in uninfected animals 4 h p.i. 20 days after surgery: 1.75 +/- 0.48 vs 1.13 +/- 0.11, p = 0.04. From 1 h to 4 h p.i., ONKR increased in 9/12 infected and 0/7 uninfected animals. According to UBI uptake intensity and kinetics, scintigraphy was truly positive in all infected cases on day 9 and in four of six infected cases on day 20. It was truly negative in two of three sterile inflamed prosthetic knees on day 9, and in all cases on day 20. Biodistribution studies revealed increased UBI uptake in periprosthetic tissues in all animals 9 days after surgery, and only in infected animals on day 20.
  
  
  CONCLUSIONS
  In this experimental study, (99m)Tc-UBI 29-41 scintigraphy permitted the early detection of acute prosthetic joint infection, and exclusion of infection in chronic sterile prosthetic joint inflammation.
authors.affiliation: Université Denis Diderot-Paris 7, UMR S773, F-75018 Paris, France. sarda@bichat.inserm.fr
authors.forename: Laure
authors.initials: L
authors.lastname: Sarda-Mantel
authors.forename: Azzam
authors.initials: A
authors.lastname: Saleh-Mghir
authors.forename: Mick M
authors.initials: MM
authors.lastname: Welling
authors.forename: Alain
authors.initials: A
authors.lastname: Meulemans
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Vrigneaud
authors.forename: Olivier
authors.initials: O
authors.lastname: Raguin
authors.forename: Florence
authors.initials: F
authors.lastname: Hervatin
authors.forename: Geneviève
authors.initials: G
authors.lastname: Martet
authors.forename: Françoise
authors.initials: F
authors.lastname: Chau
authors.forename: Rachida
authors.initials: R
authors.lastname: Lebtahi
authors.forename: Dominique
authors.initials: D
authors.lastname: Le Guludec
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry; D005121:Extremities / Q000000981:diagnostic imaging; D005260:Female; D015902:Gamma Cameras; D007596:Joints / Q000382:microbiology*; D015609:Organotechnetium Compounds; D010446:Peptide Fragments; D011475:Prosthesis Failure; D011817:Rabbits; D011849:Radioactive Tracers; D011877:Radionuclide Imaging / Q000379:methods*; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000378:metabolism*
chemical_list: D023181:Antimicrobial Cationic Peptides; D015609:Organotechnetium Compounds; D010446:Peptide Fragments; D011849:Radioactive Tracers; C485080:technetium 99m ubiquicidin(29-41)