Better Diagnostics, More Collaboration Needed to Deal with Antimicrobial Resistance

In low-income countries, doctors often face a dilemma when treating patients with respiratory illnesses of an unknown cause. Do they wait for diagnostic tests, which can take time, if they are available at all? Or do they hedge their bets and start patients on antibiotics, which may not be necessary or effective?

When doctors choose the latter option, they may contribute to a growing global problem of antimicrobial resistance, or AMR. Overuse of antibiotics is a main driver in the evolution of drug-resistant bacteria, turning previously treatable infections lethal. More than 1 million people die from drug-resistant infections each year, a number that is expected to increase dramatically without new strategies to prevent microbes from developing resistance. 

“This is a silent, rapidly growing threat straining health systems worldwide,” said Ganga Moorthy, M.D., an assistant professor of pediatric infectious diseases and global health at Duke, during a March 5 Think Global event focused on AMR. 

Speakers at the event, hosted by the Duke Global Health Institute, discussed approaches that are being tried to prevent AMR, including expanding access to rapid diagnostics to help doctors guide treatment decisions. 

"It’s well recognized diagnostics are a cornerstone in managing infectious diseases and figuring out what’s causing an infection to avoid unnecessary antimicrobial use,” said Gayani Tillekeratne, M.D., an associate professor of medicine and global health at Duke who studies emerging infectious diseases in Sri Lanka. 

Tillekeratne noted one study that found 80 percent of doctors in Sri Lanka prescribed antibiotics to patients who later tested positive for influenza, a viral infection for which antibiotics are not effective. When doctors were encouraged to use rapid tests to screen for flu, antibiotic use dropped, but they were still given in a majority of cases, she said. 

Diagnostics are only one part of a “whole-system approach” that is necessary to combat AMR, noted Don Goldmann, M.D., a professor of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health. He said that many steps have to be in place just to get clinicians timely lab results, and even then, clinicians may not have a full understanding of the risks of using an antimicrobial drug in certain situations.

“It’s a complex system where failure at any one point can lead to failure in patient treatment,” Goldmann said. 

Siddhartha Thakur, Ph.D., executive director of North Carolina State University’s Global One Health Academy, advocated for an even wider lens on the problem, saying it is critical to understand the evolution of pathogens in environments where plants, animals and humans overlap, such as farms and food processing plants. He pointed to the use of antibiotics in food animals as a source of antimicrobial resistance in humans that has not been well studied.

“I don’t think we have used the right approach to tackle AMR problems,” he said. “There’s a huge environmental side that is often neglected or totally ignored.”

Thakur said a lack of trust and cooperation among medical research, agricultural industries and environmental scientists has prevented a more integrated approach, which could benefit both surveillance of resistant microbes and development of new antimicrobials.

Moorthy, a DGHI Master of Science in Global Health alumna who moderated the event, also noted that environmental factors such as climate change contribute to microbes evolving drug resistance. 

David McAdams, Ph.D., a professor of business administration and economics at Duke’s Fuqua School of Business. Discussed research in which he applies the economic principles of game theory to find more effective strategies to prevent AMR. He explained that when doctors know whether they are dealing with resistant strains, they can choose the most effective treatment and avoid using antimicrobials that will only expand resistance. 

 “What matters most is caregivers and public health authorities have both the capacity and incentive to deploy diagnostic-informed, transmission-disrupting interventions targeted against the resistant strain,” said McAdams, who is a DGHI affiliate. 

But Tillekeratne noted that more needs to be done to make both doctors and patients aware of the need for caution in using antimicrobials.

“In addition to clinicians, educating the community and patients about what antibiotics are, what they’re used for and when they shouldn’t be used is important,” she said. “More awareness and communication between these communities will be helpful."