Evaluation of 99mTc-UBI 29-41 scintigraphy for specific detection of experimental Staphylococcus aureus prosthetic joint infections
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99mTc-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.
Left knee arthroplasty was performed on 20 New Zealand rabbits, then 107 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.
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.
In this experimental study, 99mTc-UBI 29-41 scintigraphy permitted the early detection of acute prosthetic joint infection, and exclusion of infection in chronic sterile prosthetic joint inflammation.
KeywordsAntimicrobial peptide Technetium Rabbits Prosthetic joint infection Scintigraphy
- 6.Osmon DR, Hanssen AD, Patel R. Prosthetic joint infection: criteria for future definitions. Clin Orthop Relat Res 2005:89–90.Google Scholar
- 10.Patel R, Osmon DR, Hanssen AD. The diagnosis of prosthetic joint infection: current techniques and emerging technologies. Clin Orthop Relat Res 2005:55–8.Google Scholar
- 17.Larikka MJ, Ahonen AK, Niemela O, Junila JA, Hamalainen MM, Britton K, et al. Comparison of 99mTc ciprofloxacin, 99mTc white blood cell and three-phase bone imaging in the diagnosis of hip prosthesis infections: improved diagnostic accuracy with extended imaging time. Nucl Med Commun 2002;23:655–61.CrossRefPubMedGoogle Scholar
- 29.Belmatoug N, Cremieux AC, Bleton R, Volk A, Saleh-Mghir A, Grossin M, et al. A new model of experimental prosthetic joint infection due to methicillin-resistant Staphylococcus aureus: a microbiologic, histopathologic, and magnetic resonance imaging characterization. J Infect Dis 1996;174:414–7.PubMedGoogle Scholar