Discovery of Drug-Resistant Vibrio Bacteria in Israeli Seawater
Researchers from Tel Aviv University have identified drug-resistant Vibrio bacteria in seawater samples collected from beaches in Tel Aviv, Ma’agan Michael, and the Gulf of Eilat. These bacteria pose health risks to both humans and marine animals, and their link to antibiotic resistance is increasingly concerning.
The research was conducted by doctoral student Katarzyna Kanarek under the supervision of Prof. Dor Salomon and Prof. Motti Gerlic in the university’s Department of Microbiology and Clinical Immunology. The findings were published in the mSphere journal with funding from Tel Aviv University’s Center for Combating Pandemics.
“Vibrio is a large family of bacteria found in saltwater environments,” noted Prof. Salomon. “Many of these strains can be harmful to humans and marine life. What’s particularly alarming is their ability to exchange genetic material, including traits that help them attack immune cells. They also thrive in warmer waters, which means, as global temperatures rise, we may see more widespread infections.”
While Israel hasn’t experienced significant outbreaks linked to Vibrio in recent decades, reports from the Health Ministry indicate a gradual increase in isolated Vibrio strains in patients. These bacteria can cause various ailments, including gastrointestinal issues and ear infections, as well as significant harm to marine life like corals and shellfish.
A notable outbreak occurred in 1996 with Vibrio vulnificus, often referred to as a “flesh-eating” bacterium. “We aimed to assess the epidemic potential of Vibrio in marine settings,” Salomon explained.
In the summer of 2023, the team collected water samples from the Mediterranean and Red Seas. They sequenced the genomes of 23 local Vibrio strains and evaluated their capacity to harm immune cells—a shocking half of the samples effectively did so. Although no strain was universally resistant to all known antibiotics, many showed significant resistance to azithromycin, a commonly used treatment.
Additionally, researchers identified a bacterium from the Red Sea producing a toxin that has been associated with serious damage to shrimp farms in Southeast Asia and the Americas. The presence of such a toxin in Israeli waters raises flags about the potential for local bacteria to develop similar capabilities, which could threaten domestic aquaculture.
While there isn’t an immediate cause for concern, the research team is pushing for stricter monitoring of Vibrio in Israel’s coastal waters. “Monitoring efforts here tend to focus primarily on hospitals,” Salomon mentioned.
“Israel’s national Vibrio monitoring center examines strains from patients and assesses their antibiotic resistance. However, strains that may seem innocuous today could turn hazardous down the line, particularly for humans or marine farming. The potential for pathogenicity already exists in our regions.”
He urged local authorities to implement a structured monitoring system—before any infections occur—and recommended public caution. “Avoid swimming with open wounds,” he advised, “and exercise care with raw seafood, especially shellfish, as they can filter and accumulate bacteria from the surrounding water.”
