Résumé
Ubiquicidin [UBI] 29-41 is a synthetic antimicrobial peptide that binds with the microbial cell membrane at the location of infection. This study was conducted to evaluate its probable efficacy as an infection-imaging agent with potential to differentiate bacterial infection from sterile inflammation in humans. Fifteen diabetic foot patients [10 males and 5 females] with suspected bacterial infection, prior to starting antibiotic treatment, were selected for this study. First a routine three phase bone scan and later a [99m]Tc-UBI scan was performed for all the patients. 555-740 MBq of [99m]Tc-UBI was injected intravenously. A 10 minute dynamic study was followed by spot views of the suspected region of infection and corresponding normal areas [liver and kidneys] at 60 and 120 min. Whole-body anterior and posterior images were also acquired. To interpret the studies as positive or negative, visual score [0 -3] was used, with scores of 0 [minimal or no uptake; equivalent to soft tissue] and 1 [mild; less uptake than in liver] being considered negative and scores of 2 [moderate; uptake equal to or greater than that in liver] and 3 [intense uptake equal to or greater than that in kidneys] being considered positive. Of 15 studies performed with [99m]Tc-UBI, all had positive bacterial cultures. The result of bone scan was positive for osteomyelitis in 12 patients [80%]. [99m]Tc-UBI Scintigraphy was positive in 6 patients, but negative in nine. The sensitivity of [99m]Tc-UBI for detection of infection was therefore 40%. From 12 patients who had positive bone scans, only 6 had a positive [99m]Tc-UBI [50%] indicating the sensitivity of 50% for [99m]Tc-UBI in osteomyelitis cases. 99mTc-UBI was not positive in any patient who had evidence of soft tissue infection in the bone scan. Although [99m]Tc-UBI 29-41 was well tolerated by all the patients without any side effects, considering low sensitivity of this agent, this radiopharmaceutical is not of great value for diabetic foot infection diagnosis