ORIGINAL ARTICLE |
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Year : 2021 | Volume
: 20
| Issue : 3 | Page : 266-272 |
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Evaluation of 68Ga-DOTA-Ubiquicidin (29–41) for imaging Staphylococcus aureus (Staph A) infection and turpentine-induced inflammation in a preclinical setting
Dilip Kumar Boddeti1, Vijay Kumar2
1 Department of Nuclear Medicine and PET, Westmead Hospital; Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead; Westmead Clinical School, University of Sydney, Sydney NSW, Australia 2 Department of Nuclear Medicine and PET, Westmead Hospital; Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead; Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney NSW, Australia
Correspondence Address:
Prof. Vijay Kumar Department of Nuclear Medicine and PET, Westmead Hospital, Westmead 2145, NSW Australia
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/wjnm.WJNM_103_20
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Synthetic antimicrobial peptide fragment, 99mTc-Ubiquicidin 29–41, is shown to be sensitive and also specific for imaging bacterial infections. We undertook this study to explore the advantage of using a positron emission agent, 68Ga-DOTA-Ubiquicidin 29–41 (68Ga-DOTA-UBI), for detecting Staph-A infection in an animal model, and also evaluated its ability to distinguish a turpentine-induced sterile inflammation in an animal model. Pure Ga-68 was freshly eluted from a 68Ge/68Ga generator (IGG-100). DOTA-UBI (50 μg) was ra diolabeled with pure Ga-68 (500MBq) by incubating the reaction mixture at pH 4.5 for 10 min, 95°C. Rats were infected with Staph-A at the hind leg joint of rats to form bacterial abscess. Sterile inflammation was induced in the right thigh muscle by injecting 200 μl of 100% turpentine oil. Rats were injected intravenously with 10–15 MBq of tracer, and images were acquired at different time intervals with Siemens (Biograph mCT) positron emission tomography computed tomography scanner. The early images at 6 min postinjection clearly indicated mild uptake of the agent corresponding to the infection site, which increased dramatically at 20, 30, and 60 min postinjection. The target to background ratio (T/B) increased significantly over the same time period of study (1.6, 4.2, and 6.1, respectively). There was a mild uptake of 68Ga-DOTA-UBI at the site corresponding to sterile inflammation at 6 min postinjection, which was rapidly washed off as seen at 25 and 45 min images. The images indicated fast clearance of the agent from liver and soft tissues within 6 min. Control rats showed similar biodistribution of activity. The mild uptake of 68Ga-DOTA-UBI at the corresponding Staph-A infection lesion and very fast kinetics of clearance from the blood pool and soft tissues suggested a very high clinical potential for this agent. The absence of uptake of the agent at sterile inflammation site suggests that the agent may be useful in distinguishing infection from inflammation. |
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