Role of 99mTc-ubiquicidin 29-41 scintigraphy to monitor antibiotic therapy in patients with orthopedic infection: a preliminary study.

ABSTRACT

INTRODUCTION: Ubiquicidin (UBI) 29-41 is a cationic synthetic antimicrobial peptide fragment that binds preferentially with anionic microbial cell membranes at the site of infection. This study evaluated the potential ability of Tc-UBI 29-41 to assess response to antibiotic therapy in orthopedic infection. METHODS: A total of 12 patients, 10 men and two women (mean age, 41.6 years; range, 23-75 years), with suspected orthopedic infection (bone, soft tissue, or prosthesis) and positive Tc-UBI scan for infection were included in the study. One day after the Tc-UBI scan, a bone scan was performed as well. After this evaluation, eight of the nine treated cases responded to the treatment. Then, one nonresponder patient and two nontreated patients of three cases underwent antibiotic therapy and were evaluated again 10-14 days later. After this, one of the two patients not treated the first time responded to therapy and two patients did not. Moreover, one patient refused to undergo therapy both the first and second time. Thus, 11 treated cases were analyzed in this study and divided in two groups (a) nine treated responders and (b) two treated nonresponders. In all patients, erythrocyte sedimentation rate and C-reactive protein were measured and also wound cultures were assessed. RESULTS: Quantitative analysis of erythrocyte sedimentation rate, C-reactive protein, and bone scan before and after the 10-14-day interval showed no significant change in either group, but a quantitative Tc-UBI scan at 30, 60, and 120 min after tracer injection indicated significant reduction in radiotracer uptake after the 10-14-day interval compared with the Tc-UBI scan before this interval in the responder group, and no significant change in the nonresponder group. CONCLUSION: The Tc-UBI scan can determine response to antibiotic therapy in orthopedic infection in humans.