A tiny worm lives unhindered by bacteria somewhere on the Pacific Ocean floor in nearly freezing water under pressure strong enough to destroy most life. It’s not a coincidence. Researchers have long suspected that some of the planet’s harshest habitats, where sunlight never reaches and temperatures are barely above freezing, are secretly creating chemistry that may save lives. A growing amount of evidence now indicates that they were correct.
For decades, the pipeline of antibiotics has essentially stalled. Since 1980, only two truly novel classes of antibiotics have been approved, and the bugs are quickly catching up. Globally, antimicrobial resistance already claims the lives of an estimated 1.2 million people annually. In the US alone, the CDC has identified eighteen drug-resistant bacterial threats. Twelve bacterial families have been identified by the World Health Organization as serious threats to human health. The majority of the medications currently in use were found during the heyday of antibiotic research, which came to an end sometime in the middle of the 20th century. It’s a slow-moving emergency.
Because of this, current deep-sea bioprospecting research feels more urgent than merely fascinating. Darobactin, a novel antibiotic compound, was discovered to be concealed in the gut of a nematode, a tiny parasitic worm found in soil, by researchers at Northeastern University under the direction of biologist Kim Lewis.
The compound was created by the bacteria called Photorhabdus that lived inside this worm, not for human benefit but merely to survive. For the first time, an antibiotic found in an animal’s microbiome had genuine potential for use in humans. Darobactin eliminated E. coli and Klebsiella pneumoniae infections in mice without showing any toxicity. Lewis himself pointed out that there had never been an antibiotic with a structure like this.
Alvinella pompejana, also referred to as the Pompeii worm, is a polychaete worm that lives on deep-sea hydrothermal vents and withstands temperatures and chemical conditions that would kill most living things. Researchers studying it discovered that the worm itself produces a peptide called alvinellacin that kills Pseudomonas aeruginosa and Staphylococcus aureus, two of the most tenacious pathogens causing lung infections in people with cystic fibrosis. This is especially remarkable because alvinellacin remains effective even in the oxygen-poor, chemically hostile environment found inside a diseased lung. There, conventional antibiotics lose their effectiveness. This one doesn’t. Additionally, bacteria exposed to it did not develop resistance after more than a month of testing.
That final point is worth pausing on. It’s not just a nice bonus that resistance cannot be triggered. Perhaps the entire issue with current medications is this. Bacteria change over time. Over time, they have developed a workaround for every antibiotic we have given them. Compounds that were created in settings where chemical ingenuity has been necessary for survival for millions of years appear to function differently, attacking bacterial membranes in ways that are difficult to stop.
For more than thirty years, the Harbor Branch Oceanographic Institute at Florida Atlantic University has been quietly preparing for this day. Over half of the approximately 19,000 marine microorganisms that scientists have gathered there come from depths greater than 45 meters. More than 1,000 strains of actinobacteria, the same group that produces more than half of all antibiotics currently in use, are included in those collections. Over half of the 50 strains of deep-sea sponges screened in the study exhibited antimicrobial activity. One strain produced substances that were more effective than vancomycin against C. difficile, a pathogen that kills almost 30,000 people in the US each year.
Researchers from New Zealand have expanded this narrative. A compound was extracted from a deep-sea sponge that was collected from 800 meters below the surface off the Kermadec Ridge by marine biologists at the University of Auckland. Theoretically, the molecule makes it more difficult for bacteria to evolve around it because it seems to disrupt bacterial cell walls through a mechanism different from any currently in use. 99 percent of multidrug-resistant infections were eradicated in lab tests without showing any signs of harm to human cells.
This is not going to be a complete remedy. The pharmaceutical economics of antibiotic development are still very depressing—drugs you take for ten days aren’t as profitable as drugs you take for life—and phase I human trials for some of these compounds are still years away. However, this body of evidence suggests that the ocean floor is starting to provide what terrestrial soil can no longer consistently provide. The majority of this planet is covered by the deep sea. Very little has been done to search it. And for longer than medicine has existed, it has been conducting its own chemistry in the dark and under unimaginable pressure.
