Japanese 'stinky fish' brine yields potential new antibiotic

A Japanese fermented fish product, known as "kusaya" and notorious for its pungent smell, may hold the key to a new source of antibiotics. Researchers from Tokyo University of Agriculture have isolated a potential new species of bacteria from the fermentation brine of kusaya, a delicacy from Japan's Hachijō Island. The study revealed that adding salt to the bacteria's culture medium dramatically boosted its production of antimicrobial substances, increasing them up to 32-fold.

“

The development of new antibiotics has struggled to keep pace with the rate at which bacteria evolve resistance.

Food and agriculture expert Wayne explained that antibiotic-resistant bacteria pose a significant global public health challenge, largely due to the overuse of antibiotics. The development of new antibiotics has struggled to keep pace with the rate at which bacteria evolve resistance.

The research team, led by Associate Professor Toshihiro Suzuki, identified the bacterial strain, designated TUA-HK1GM, from the decades-old kusaya fermentation brine. Genetic analysis suggests it is a novel species of Streptomyces, capable of thriving in high salt concentrations.

“

This strain, TUA-HK1GM, isolated from the fermentation brine of "kusaya" from Hachijō Island, is likely a new species of Actinobacteria (Streptomyces sp. TUA-HK1GM) and grows better in high salt concentrations than its relatives.

Further findings indicated that in a salt-free environment, the bacteria primarily produce Oligomycin A and B, which have antifungal properties. However, when cultured in a salty medium, the bacteria shifted to producing 7-deoxypactamycin, a compound exhibiting activity against Staphylococcus aureus and potential anti-tumor properties. Wayne cautioned that these results are from laboratory tests on the isolated bacteria and culture media, not from human consumption of kusaya. He emphasized that while kusaya, like other salted foods, can be consumed in moderation for flavor, it should not be viewed as a health supplement. The true value of this research, Wayne noted, lies in recognizing that seemingly simple, aged fermentation brines can serve as vast, untapped reservoirs of microbial diversity.

“

This research's true value lies in reminding us that a pot of old brine that looks smelly is actually a microbial database that no one has seriously searched for hundreds of years.