Real-Time Bacterial Tracking For Improved Treatments

By Chuck Seegert, Ph.D.

Researchers from Johns Hopkins have shown in mice that the epicenter of bacterial infection and the type of bacteria itself can be imaged accurately. This advance could change the way infections are treated, and could lead to a reduction in antibiotic use.

Infections are often treated using antibiotics to kill the bacteria at the heart of the condition. Unfortunately, however, the effectiveness of the antibiotics at treating a specific microorganism is difficult to ascertain. Different kinds of antibiotics are more effective against specific strains of bacteria and, if the wrong antibiotic is chosen, a patient’s infection may worsen.

A new method that involves positron emission tomography (PET) and contrast agents may change things completely, according a recent press release from John’s Hopkins University.

“What we have produced is essentially a system that localizes the epicenter of infection and provides real-time tracking of bacterial activity, giving us rapid feedback on how the bacteria respond to antibiotics,” said principal investigator Sanjay Jain, M.D., an infectious disease specialist at the Johns Hopkins Children’s Center and director of the Center for Inflammation Imaging and Research at Johns Hopkins, in the press release.

Using off-the-shelf technology, the team devised a marker specific to Gram-negative bacteria called 2-[¹⁸F]-fluorodeoxysorbitol (¹⁸F-FDS), according to a study published by the team in Science Translational Medicine. The compound is selectively assimilated by Gram-negative bacteria and non-mammalian cells, or Gram-positive bacteria. Through the use of a PET scanner, the bacteria can be localized and a concentration can be determined.

This method is ideal because it allows the identification of virulent forms of Enterobacteriaceae, which include germs like E. coli, Klebsiella, and Salmonella.

“Our approach could quickly and reliably detect infections caused by certain Gram-negative organisms and could speed up diagnosis and treatment by eliminating days-long waits for lab test results,” said study co-author Edward Weinstein, M.D., Ph.D., an infectious disease specialist at the Johns Hopkins University School of Medicine, in the press release.

Determining whether a bacteria is resistant to antibiotics is an important step in the diagnostic process of an infection. Recently, rapid diagnostic tests were also introduced to evaluate this type of bacterial resistance.