New PET tracer will play ‘vital role’ in identifying bacterial heart infections

Scientists have developed a novel PET radiotracer that outpaces current methods of imaging for cardiovascular bacterial infections, according to research presented at the 2018 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging in Philadelphia, Pennsylvania. 

“Early diagnosis is crucial for proper patient management, as early treatment can improve prognosis and patient outcome,” co-researcher Mirwais Wardak, PhD, of Stanford University School of Medicine in California, said in a release. “In the clinic right now, we really lack the tools to be able to specifically image bacterial infections.”

So, with the support of Stanford and the National Institutes of Health, Wardak and a team developed 6"-[18F]Fluoromaltotriose, a positron emission tomography tracer that’s transported to bacterial cells using the maltodextrin transporter. The transporter is exclusive to bacteria, Wardak said, so it’s ideal for imaging infections in the mammalian heart.

The researchers tested the diagnostic accuracy of 6"-[18F]Fluoromaltotriose in a Staphylococcus aureus-induced endocarditis mouse model. The tracer was able to image valvular infection with high sensitivity and specificity, with a 2.5-fold higher mean tracer uptake in the aortic valves of infected mice than their healthy counterparts. 

“The results of this research overcome several fundamental limitations of current methods and promise to significantly impact the clinical management of patients suffering from diseases of bacterial origin,” Wardak said. “We believe that 6"-[18F]Fluoromaltotriose PET/CT will play a vital role in the detection and monitoring of bacterial infection in patients, for example as a result of cardiovascular infection, infection after surgery, medical device-related infections, fever of unknown origin, et cetera. We also believe that PET imaging with 6"-[18F]Fluoromaltotriose will be helpful in the assessment of antibiotic therapy.”

The team is currently working on integrating the radiotracer into clinical practice, and Wardak said it could have implications that supersede infectious disease.

“For example, this tracer could be used to image the homing of bacteria against tumors and could, therefore, be used to monitor bacteria that have been trained to kill tumors,” Wardak said.