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Kahts M, Summers B, Gutta A, Pilloy W, Ebenhan T. Recently developed radiopharmaceuticals for bacterial infection imaging. EJNMMI Radiopharm Chem 2024; 9:49. [PMID: 38896373 PMCID: PMC11187059 DOI: 10.1186/s41181-024-00279-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 06/10/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND Infection remains a major cause of morbidity and mortality, regardless of advances in antimicrobial therapy and improved knowledge of microorganisms. With the major global threat posed by antimicrobial resistance, fast and accurate diagnosis of infections, and the reliable identification of intractable infection, are becoming more crucial for effective treatment and the application of antibiotic stewardship. Molecular imaging with the use of nuclear medicine allows early detection and localisation of infection and inflammatory processes, as well as accurate monitoring of treatment response. There has been a continuous search for more specific radiopharmaceuticals to be utilised for infection imaging. This review summarises the most prominent discoveries in specifically bacterial infection imaging agents over the last five years, since 2019. MAIN BODY Some promising new radiopharmaceuticals evaluated in patient studies are reported here, including radiolabelled bacterial siderophores like [68Ga]Ga-DFO-B, radiolabelled antimicrobial peptide/peptide fragments like [68Ga]Ga-NOTA-UBI29-41, and agents that target bacterial synthesis pathways (folic acid and peptidoglycan) like [11C]para-aminobenzoic acid and D-methyl-[11C]-methionine, with clinical trials underway for [18F]fluorodeoxy-sorbitol, as well as for 11C- and 18F-labelled trimethoprim. CONCLUSION It is evident that a great deal of effort has gone into the development of new radiopharmaceuticals for infection imaging over the last few years, with remarkable progress in preclinical investigations. However, translation to clinical trials, and eventually clinical Nuclear Medicine practice, is apparently slow. It is the authors' opinion that a more structured and harmonised preclinical setting and well-designed clinical investigations are the key to reliably evaluate the true potential of the newly proposed infection imaging agents.
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Affiliation(s)
- Maryke Kahts
- Pharmaceutical Sciences Department, School of Pharmacy, Sefako Makgatho Health Sciences University, Ga-Rankuwa, 0208, South Africa.
| | - Beverley Summers
- Pharmaceutical Sciences Department, School of Pharmacy, Sefako Makgatho Health Sciences University, Ga-Rankuwa, 0208, South Africa
| | - Aadil Gutta
- Nuclear Medicine Department, Dr George Mukhari Academic Hospital, Ga-Rankuwa, 0208, South Africa
- School of Medicine, Sefako Makgatho Health Sciences University, Ga-Rankuwa, 0208, South Africa
| | - Wilfrid Pilloy
- Nuclear Medicine Department, Dr George Mukhari Academic Hospital, Ga-Rankuwa, 0208, South Africa
| | - Thomas Ebenhan
- Nuclear Medicine Department and Nuclear Medicine Research Infrastructure, University of Pretoria, Pretoria, 0001, South Africa
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Lochenie C, Duncan S, Zhou Y, Fingerhut L, Kiang A, Benson S, Jiang G, Liu X, Mills B, Vendrell M. Photosensitizer-Amplified Antimicrobial Materials for Broad-Spectrum Ablation of Resistant Pathogens in Ocular Infections. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2404107. [PMID: 38762778 DOI: 10.1002/adma.202404107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/17/2024] [Indexed: 05/20/2024]
Abstract
The emergence of multidrug resistant (MDR) pathogens and the scarcity of new potent antibiotics and antifungals are one of the biggest threats to human health. Antimicrobial photodynamic therapy (aPDT) combines light and photosensitizers to kill drug-resistant pathogens; however, there are limited materials that can effectively ablate different classes of infective pathogens. In the present work, a new class of benzodiazole-paired materials is designed as highly potent PDT agents with broad-spectrum antimicrobial activity upon illumination with nontoxic light. The results mechanistically demonstrate that the energy transfer and electron transfer between nonphotosensitive and photosensitive benzodiazole moieties embedded within pathogen-binding peptide sequences result in increased singlet oxygen generation and enhanced phototoxicity. Chemical optimization renders PEP3 as a novel PDT agent with remarkable activity against MDR bacteria and fungi as well as pathogens at different stages of development (e.g., biofilms, spores, and fungal hyphae), which also prove effective in an ex vivo porcine model of microbial keratitis. The chemical modularity of this strategy and its general compatibility with peptide-based targeting agents will accelerate the design of highly photosensitive materials for antimicrobial PDT.
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Affiliation(s)
- Charles Lochenie
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Sheelagh Duncan
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Yanzi Zhou
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Leonie Fingerhut
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Alex Kiang
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Sam Benson
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Guanyu Jiang
- Fluorescence Research Group, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Xiaogang Liu
- Fluorescence Research Group, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Bethany Mills
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Marc Vendrell
- Centre for Inflammation Research, University of Edinburgh, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, 4-5 Little France Drive, Edinburgh, EH16 4UU, UK
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Bhatt Mitra J, Chatterjee S, Kumar A, Khatoon E, Chandak A, Rakshit S, Bandyopadhyay A, Mukherjee A. Expanding a peptide-covalent probe hybrid for PET imaging of S. aureus driven focal infections. EJNMMI Radiopharm Chem 2024; 9:25. [PMID: 38530487 DOI: 10.1186/s41181-024-00252-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/04/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND The urgent demand for innovative theranostic strategies to combat bacterial resistance to antibiotics is evident, with substantial implications for global health. Rapid diagnosis of life-threatening infections can expedite treatment, improving patient outcomes. Leveraging diagnostic modalities i.e., positron emission tomography (PET) and single photon emission computed tomography (SPECT) for detecting focal infections has yielded promising results. Augmenting the sensitivity of current PET and SPECT tracers could enable effective imaging of pathogenic bacteria, including drug-resistant strains.UBI (29-41), an antimicrobial peptide (AMP) fragment recognizes the S. aureus membrane through electrostatic binding. Radiolabeled UBI (29-41) is a promising SPECT and PET-based tracer for detecting focal infections. 2-APBA (2-acetyl-phenyl-boronic acid), a non-natural amino acid, specifically targets lysyl-phosphatidyl-glycerol (lysyl-PG) on the S. aureus membranes, particularly in AMP-resistant strains. We propose that combining UBI with 2-APBA could enhance the diagnostic potential of radiolabeled UBI. RESULTS Present work aimed to compare the diagnostic potential of two radiolabeled peptides, namely UBI (29-41) and 2-APBA modified UBI (29-41), referred to as UBI and UBI-APBA. APBA modification imparted antibacterial activity to the initially non-bactericidal UBI against S. aureus by inducing a loss of membrane potential. The antibacterial activity demonstrated by UBI-APBA can be ascribed to the synergistic interaction of both UBI and UBI-APBA on the bacterial membrane. To enable PET imaging, we attached the chelator 1,4,7-triazacyclononane 1-glutaric acid 4,7-acetic acid (NODAGA) to the peptides for complexation with the positron emitter Gallium-68 (68Ga). Both NODAGA conjugates were radiolabeled with 68Ga with high radiochemical purity. The resultant 68Ga complexes were stable in phosphate-buffered saline and human serum. Uptake of these complexes was observed in S. aureus but not in mice splenocytes, indicating the selective nature of their interaction. Additionally, the APBA conjugate exhibited superior uptake in S. aureus while preserving the selectivity of the parent peptide. Furthermore, [68Ga]Ga-UBI-APBA demonstrated accumulation at the site of infection in rats, with an improved target-to-non-target ratio, as evidenced by ex-vivo biodistribution and PET imaging. CONCLUSIONS Our findings suggest that linking UBI, as well as AMPs in general, with APBA shows promise as a strategy to augment the theranostic potential of these molecules.
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Affiliation(s)
- Jyotsna Bhatt Mitra
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India
| | - Saurav Chatterjee
- Biomimetic Peptide Engineering Laboratory, Department of Chemistry, Indian Institute of Technology Ropar, Ropar, Punjab, India
| | - Anuj Kumar
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Elina Khatoon
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Ashok Chandak
- Board of Radiation and Isotope Technology, Navi Mumbai, India
| | | | - Anupam Bandyopadhyay
- Biomimetic Peptide Engineering Laboratory, Department of Chemistry, Indian Institute of Technology Ropar, Ropar, Punjab, India.
| | - Archana Mukherjee
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India.
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Nogueira SA, Barboza MRFFD, Bezerra RP, Cabeza JM, Dell'Aquila AM, Santos DDCB, Yamaga LYI, Osawa A. Antimicrobial peptide for bacterial infection imaging: first case reported in Brazil. EINSTEIN-SAO PAULO 2023; 21:eRC0621. [PMID: 38055555 DOI: 10.31744/einstein_journal/2023rc0621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/14/2023] [Indexed: 12/08/2023] Open
Abstract
Molecular imaging markers can be used to differentiate between infection and aseptic inflammation, determine the severity of infection, and monitor treatment responses. One of these markers is ubiquicidin(29-41) (UBI), a cationic peptide fragment that binds to the bacterial membrane wall and is labeled with gallium-68 (68Ga), a positron emitter radioisotope. The use of UBI in positron emission tomography (PET)/computed tomography (CT) for improved detection of lesions has been receiving considerable attention recently. Herein, we report the first case of 68Ga-UBI PET/CT performed in Brazil. The patient was a 39-year-old woman referred for a scan to confirm a clinical suspicion of chronic osteomyelitis of her fractured left tibia. PET images revealed radiotracer uptake near the posterior contour of the tibial fracture focus and the fixation plate, in the soft tissue around the distal half of the tibia, and in the non-consolidated fracture of the left distal fibula. Surgery for local cleaning was performed, and culture of a specimen collected from the surgical site confirmed the presence of Staphylococcus aureus. In the present case, 68Ga-UBI PET/CT, a non-invasive imaging modality, identified the infection foci in vivo, indicating its potential for clinical use.
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Affiliation(s)
- Solange Amorim Nogueira
- Department of Radiology and Diagnostic Imaging, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
| | | | - Rosemeire Pereira Bezerra
- Department of Radiology and Diagnostic Imaging, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
| | - Jorge Mejia Cabeza
- Department of Radiology and Diagnostic Imaging, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
| | - Adriana Macedo Dell'Aquila
- Department of Medicine and Infectious Diseases, Hospital do Servidor Público Estadual de São Paulo, São Paulo, SP, Brazil
| | | | - Lilian Yuri Itaya Yamaga
- Department of Radiology and Diagnostic Imaging, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
| | - Akemi Osawa
- Department of Radiology and Diagnostic Imaging, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
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Nogueira SA, de Barboza MF, Dell’Aquila AM, Santos DCB, Osawa A. Could 68 Ga-DOTA-UBI-29-41 Help Identify Chronic Osteomyelitis on PET/CT Images? A Pilot Study. Clin Nucl Med 2023; 48:982-984. [PMID: 37756436 PMCID: PMC10581417 DOI: 10.1097/rlu.0000000000004866] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/06/2023] [Indexed: 09/29/2023]
Abstract
ABSTRACT This pilot study aimed to confirm the presence of infectious agents in infection foci using PET/CT imaging with 68 Ga-DOTA-UBI (29-41) in 7 patients with chronic osteomyelitis and with indications for surgical cleaning at the site of the infection focus. The whole-body PET/CT was performed on Biograph mCT 40 PET/CT scanner (Siemens Healthineers); the image began 45-60 minutes postinjection of the radiotracer (148-260 MBq). This study demonstrated that, in 6 patients in whom the PET/CT was classified as positive for identified infectious foci, confirmed by culture of the secretion sample collected during surgery, only 1 patient in antibiotic therapy was negative.
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Affiliation(s)
| | | | - Adriana M. Dell’Aquila
- Department of Orthopedics and Traumatology–Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Mitra JB, Mukherjee A, Kumar A, Chandak A, Rakshit S, Yadav HD, Pandey BN, Sarma HD. Imaging of bacterial infection: Harnessing positron emission tomography and Cherenkov luminescence imaging with UBI-derived octapeptide. Drug Dev Res 2023; 84:1513-1521. [PMID: 37571805 DOI: 10.1002/ddr.22103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/07/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023]
Abstract
Noninvasive imaging techniques for the early detection of infections are in high demand. In this study, we present the development of an infection imaging agent consisting of the antimicrobial peptide fragment UBI (31-38) conjugated to the chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), which allows for labeling with the positron emitter Ga-68. The preclinical evaluation of [68 Ga]Ga-NODAGA-UBI (31-38) was conducted to investigate its potential for imaging bacterial infections caused by Staphylococcus aureus. The octapeptide derived from ubiquicidin, UBI (31-38), was synthesized and conjugated with the chelator NODAGA. The conjugate was then radiolabeled with Ga-68. The radiolabeling process and the stability of the radio formulation were confirmed through chromatography. The study included both in vitro evaluations using S. aureus and in vivo evaluations in an animal model of infection and inflammation. Positron emission tomography (PET) and Cherenkov luminescence imaging (CLI) were performed to visualize the targeted localization of the radio formulation at the site of infection. Ex vivo biodistribution studies were carried out to quantify the uptake of the radio formulation in different organs and tissues. Additionally, the uptake of [18 F]Fluorodeoxyglucose ([18 F] FDG) in the animal model was also studied for comparison. The [68 Ga]Ga-NODAGA-UBI (31-38) complex consistently exhibited high radiochemical purity (>90%) after formulation. The complex demonstrated stability in saline, phosphate-buffered saline, and human serum for up to 3 h. Notably, the complex displayed significantly higher uptake in S. aureus, which was inhibited in the presence of unconjugated UBI (29-41) peptide, confirming the specificity of the formulation for bacterial membranes. Bacterial imaging capability was also observed in PET and CLI images. Biodistribution results indicated a substantial target-to-nontarget ratio of approximately 4 at 1 h postinjection of the radio formulation. Conversely, the uptake of [18 F]FDG in the animal model did not allow for the discrimination of infected and inflamed sites. Our studies have demonstrated that [68 Ga]Ga-NODAGA-UBI (31-38) holds promise as a radiotracer for imaging bacterial infections caused by S. aureus.
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Affiliation(s)
- Jyotsna Bhatt Mitra
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Archana Mukherjee
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Anuj Kumar
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Ashok Chandak
- Board of Radiation & Isotope Technology, Navi Mumbai, India
| | - Sutapa Rakshit
- Radiation Medicine Centre, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Hansa D Yadav
- Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Badri Narain Pandey
- Homi Bhabha National Institute, Mumbai, India
- Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
| | - Haladhar Dev Sarma
- Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre (BARC), Mumbai, India
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Roll W, Faust A, Hermann S, Schäfers M. Infection Imaging: Focus on New Tracers? J Nucl Med 2023; 64:59S-67S. [PMID: 37918846 DOI: 10.2967/jnumed.122.264869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/31/2023] [Indexed: 11/04/2023] Open
Abstract
Infections account for relevant morbidity and mortality, especially if the cardiovascular system is affected. Clinical manifestations are often unspecific, resulting in a challenging diagnostic work-up. The use of molecular imaging methods, namely [18F]FDG PET and leukocyte scintigraphy, is increasingly recognized in recently published international guidelines. However, these 2 established methods focus on the host's immune response to the pathogen and are therefore virtually unable to differentiate infection from inflammation. Targeting the microorganism responsible for the infection directly with novel imaging agents is a promising strategy to overcome these limitations. In this review, we discuss clinically approved [18F]FDG PET with its advantages and limitations in cardiovascular infections, followed by new PET-based approaches for the detection of cardiovascular infections by bacteria-specific molecular imaging methods. A multitude of different targeting options has already been preclinically evaluated, but most still lack clinical translation. We give an overview not only on promising tracer candidates for noninvasive molecular imaging of infections but also on issues hampering clinical translation.
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Affiliation(s)
- Wolfgang Roll
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
| | - Andreas Faust
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Michael Schäfers
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
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