Superbugs surrender to Civil War-era medicines

Plant remedies from the Civil War may fight modern-day drug-resistant superbugs, researchers reported in a recent article in Scientific Reports.

At the height of the Civil War—1863—a Union blockade had a stranglehold on the Confederacy. Union ships blocked Confederate ports from receiving supplies. Necessities such as medicines for the wounded—quinine, morphine, and chloroform—couldn’t reach Confederate physicians. More soldiers died from infections and diseases (and the resulting amputations) than from bullets and bayonets. Something needed to be done.

To that end, the Surgeon General of the Confederacy, Samuel Moore, commissioned botanist Francis Porcher to find and document medicinal plants that grew in Southern states, including plant remedies used by Native Americans and enslaved Africans. Porcher’s findings included 37 plant species that could be used as antiseptics to treat gangrene and other infections. From Porcher’s research, Surgeon General Moore sent out a field guide of native plant medicines to battlefield physicians. The guide detailed how to collect, prepare, and administer these plant-based treatments.

The Confederate Army still lost the war, but perhaps it didn’t lose as many wounded soldiers thanks to the makeshift medicines.

A major threat

Fast-forward 7 score and 16 years later, to the year 2019… Antibiotic-resistant pathogens pose a dangerous threat to human health. Drug-resistant superbugs are at risk of causing local or perhaps even nationwide outbreaks. Something needs to be done.

To that end, a research team that included an ethnobotanist, a virulent disease specialist, biologists, and other experts looked to the past in hopes of finding effective antibiotics for the future. Specifically, they looked in Porcher’s Civil War-era compendium, Resources of the Southern Fields and Forests. They wondered: Could some of these rudimentary plant-based antiseptics defeat modern-day pathogens?

To find out, the scientists tested three plant species sourced from the campus at Emory University, Atlanta, GA, where many of the researchers are based. Samples included two common hardwoods, white oak (Quercus alba) and tulip poplar (Liriodendron tulipifera), as well as a thorny, woody shrub called devil’s walking stick (Aralia spinosa).

The scientists tested extracts of these plants to determine their ability to inhibit growth in three species of multidrug-resistant bacteria commonly found in wound infections: Staphylococcus aureus, Klebsiella pneumoniae, and Acinetobacter baumannii—which is better known as “Iraqibacter” due to its association with wounded soldiers returning from the Iraq War.

“[Iraqibacter] is emerging as a major threat for soldiers recovering from battle wounds and for hospitals in general,” said senior author Cassandra Quave, PhD, assistant professor, Emory Center for the Study of Human Health and the School of Medicine’s Department of Dermatology.

Laboratory testing showed that white oak extracts inhibited growth in all three species of bacteria, and both white oak and tulip poplar extracts inhibited S. aureus from forming biofilms.

Extracts from devil’s walking stick inhibited both biofilm formation and quorum sensing in S. aureus. Quorum sensing is a signaling system that bacteria use to ramp up the manufacture of toxins. Blocking this system disables the bacteria from rampant growth.

“These results support that this selection of plants exhibited some antiseptic properties in the prevention and management of wound infections during the conflict,” the researchers wrote.

Next steps

First author and Emory research specialist Micah Dettweiler said: “Our research might one day benefit modern wound care, if we can identify which compounds are responsible for the antimicrobial activity.”

If the active ingredients can be identified, “it is my hope that we can then [further] test these molecules in our world-renowned models of bacterial infection,” said coauthor Daniel Zurawski, PhD, chief of pathogenesis and virulence, Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, MD.

The next logical step in this research is in vivo testing of the antibacterial properties of these extracts. In addition, the researchers are considering testing the antibacterial abilities of the 30-odd other plants named as antiseptics in Porcher’s book

“As the global spread of antibiotic-resistant strains of bacteria continues, it is increasingly important to consider all possible sources of new, and perhaps old, treatments,” the study authors concluded.