When it comes to seafood, there’s one bacteria that strikes fear into the hearts of many – Listeria monocytogenes. But there’s another lesser-known foe lurking in our fishy meals: Aeromonas. This emerging pathogen is causing illness in humans who consume undercooked fish.
To understand the threat posed by Aeromonas, researchers conducted a study in Norway, analyzing raw fish products available for purchase. They discovered 22 strains of Aeromonas across eight different species.
Study author Hyejeong Lee explains, “The results show that the mild processing these fish products receive does not guarantee that the growth of Aeromonas bacteria will be inhibited. The majority of these Aeromonas variants are possibly pathogenic and there are often several different risk factors associated with them.”
Upon analyzing the bacteria strains found in the fish, the researchers found genes that enable these pathogens to invade and destroy host cells. They also noted a high incidence of enterotoxins, substances that harm the digestive system, explaining the association between Aeromonas and gastrointestinal and extraintestinal infections.
But the researchers made an even more alarming discovery. They found evidence that Aeromonas may contribute to the growing antibiotic resistance crisis. These bacteria regularly exchange genetic material with other microbes in the sea, potentially acquiring genes that enable them to tolerate antibiotics and pass them on to other bacteria.
Lee warns, “Some strains of Aeromonas can also spread antibiotic resistance from one type of bacteria to another. Eating seafood infected by resistant bacteria is a likely way these bacteria can spread from marine animals and environments to humans.”
The researchers found multiple antimicrobial resistance genes in all Aeromonas strains, suggesting that these bacteria in the food chain could potentially be pathogenic and act as a vector for disseminating antibiotic resistance genes to other bacteria in the same environments.
This eye-opening study is published in the journal Frontiers in Microbiology.
