We've updated our Privacy Policy to make it clearer how we use your personal data. We use cookies to provide you with a better experience. You can read our Cookie Policy here.


Novel Protein Treats Sick Farmed Fish Without Risking Antibiotic Resistance

A painting of striped bass.
Credit: WikiImages / Pixabay.
Listen with
Register for free to listen to this article
Thank you. Listen to this article using the player above.

Want to listen to this article for FREE?

Complete the form below to unlock access to ALL audio articles.

Read time: 1 minute

Scientists at the United States Department of Agriculture (USDA)’s Agricultural Research Service (ARS) developed a green antibiotic alternative to treat the deadly pathogen Streptococcus iniae in hybrid striped bass, the fourth most farmed finfish in the United States, according to a recent study.  

S. iniae is the causative agent of streptococcosis, a disease prevalent in aquaculture and causes a worldwide economic loss of $150 million annually. Disease outbreaks can bankrupt fish farms and put farmers at risk of getting the disease when handling infected fish.

Current vaccines provide only short-term protection for S. iniae, and fish farmers more often rely on antibiotics to treat the disease. ARS scientists aimed to develop a natural treatment since antimicrobial resistance — a process when germs like bacteria and fungi develop the ability to fight drugs designed to kill them — is a major concern for aquaculture farmers when treating bacterial diseases. 

Want more breaking news?

Subscribe to Technology Networks’ daily newsletter, delivering breaking science news straight to your inbox every day.

Subscribe for FREE

"Together with collaborators, we developed a novel antimicrobial protein and treatment regimen, that specifically kills only Streptococcus bacteria, and does not leave any chemical residues in the environment,” said Michael Deshotel, research microbiologist at the Harry K. Dupree Stuttgart National Aquaculture Research Center in Stuttgart, Arkansas. "According to our study’s results, this protein effectively cures S. iniae infectionsinhybrid striped bass."

According to Deshotel, the protein, known as ClyX-2, showed a 95 percent survival rate for the fish in the treatment groups in comparison to the 5 percent survival rate of fish in the control groups during the study. The results showed that the protein was statistically as effective at treating S. iniae as antibiotic treatments like carbenicillin (85 percent cure rate).

In the future, Deshotel and the researchers plan to study how to treat water to prevent diseases caused by S. iniae before they can infect fish.

Reference: Deshotel MB, Dave UM, Farmer B, Kemboi D, Nelson DC. Bacteriophage endolysin treatment for systemic infection of Streptococcus iniae in hybrid striped bass. Fish & Shellfish Immunology. 2024;145:109296. doi: 10.1016/j.fsi.2023.109296

This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.