It was a real mystery. People showing up at hospitals and clinics across the US were infected with a rare and troubling strain of bacteria that was resistant to most of the drugs used to treat it.

The strain itself had never been seen before. It was Pseudomonas aeruginosa, itself nothing rare. But this one carried a genetic change that allowed it to shake off the effects of even the strongest antibiotics usually used to treat it. Where had it come from?

It took a good deal of detective work, but the US Centers for Disease Control and Prevention and state health officials finally figured out the common source was eye drops. They tracked down a couple of brands of eye lubricants and contained the outbreak.

Now they’re working to find out how this particular germ got into eye drops in the first place, and how it acquired the mutations that made it so impervious to treatment. And they’re working to make sure that it’s not still lurking in the bodies of unsuspecting people.

Dr. Maroya Walters, a CDC epidemiologist and commander in the US Public Health Service, helped lead the investigation. In this episode of One World, One Health, Dr. Walters explains how the team tracked down the source of the unusual outbreak, and how it demonstrates that superbugs know no borders.


Image of Dr. Maroya Walters of the CDC.

Dr. Maroya Spalding Walters, PhD, ScM is a CDR in the USPHS and an Epidemiologist who leads the Antimicrobial Resistance Team in the Division of Healthcare Quality Promotion at the U.S. Centers for Disease Control & Prevention (CDC). Dr. Walters completed a B.A. in Chemistry at Carleton College, and a Sc.M. in Epidemiology, and Ph.D. in Biochemistry and Molecular Biology, both from the Johns Hopkins Bloomberg School of Public Health.  She joined the Epidemic Intelligence Service at the CDC in 2011, and continued at CDC as a staff epidemiologist, joining the Division of Healthcare Quality Promotion in 2014. Dr. Walters and her team prevent the spread of antimicrobial resistance through public health prevention and response activities.


Hosted and written by Maggie Fox
Special guest: Maroya Walters
Produced and edited by Samantha Serrano
Music composed and sound edited by Raquel Krügel