Deadly Colistin-Resistance Genes Found in Imported Seafood

Researchers at the University of Georgia have identified colistin-resistance genes in bacteria present in imported shrimp and scallops sold in markets throughout Atlanta. This discovery raises alarms about the growing threat of antibiotic resistance, particularly concerning colistin, a last-resort antibiotic crucial for treating severe infections.

Colistin is available in two formulations: colistimethate sodium, which can be injected or inhaled, and colistin sulfate, typically administered orally or topically. As bacterial resistance to this antibiotic increases, experts express concerns that common dietary choices, such as seafood, could be a contributing factor to this public health issue.

The research team’s findings indicate that imported seafood may facilitate the spread of transmissible colistin resistance genes. The study, published in the journal mSphere, is significant as it reinforces earlier research from 2016, which also linked imported seafood to the presence of these resistance genes. With approximately 90% of the shrimp consumed in the United States being imported, the implications for public health are considerable.

Understanding Colistin Resistance

The colistin-resistance mechanism is primarily associated with mobile genetic elements known as mcr genes. These genes can transfer between bacteria through plasmids, allowing once-treatable infections to potentially become life-threatening. Since the initial identification of these genes, researchers have identified at least ten variants, or alleles, which indicate a rising complexity in the genetic landscape of antibiotic resistance.

The dominant bacteria found in imported shrimp typically belong to the Gram-negative genera Serratia and Aeromonas. These findings suggest that aquaculture practices in exporting countries may be a significant source of mcr genes.

Researchers emphasize the interconnectedness of our global food supply, stating, “We live in a very connected world. We move a lot, we travel a lot, our food travels, and we are going to spread whatever emerges, even across national borders.” This underscores the urgent need for enhanced monitoring systems to track and manage antimicrobial resistance on a global scale.

Implications and Future Directions

The presence of colistin-resistance genes in imported seafood is a pressing issue that warrants immediate attention. The findings prompt calls for collaboration between international health organizations and governments to implement stricter regulations in food safety and antibiotic use in agriculture.

In a related development, researchers have recently uncovered a new class of antibiotics that specifically targets Neisseria gonorrhoeae, the bacterium responsible for gonorrhea. This discovery highlights the ongoing race against time to develop new treatments in the face of rising antibiotic-resistant infections.

The potential public health implications of finding colistin-resistance genes in seafood cannot be overstated. As consumers increasingly seek out seafood as a dietary staple, awareness of the risks associated with imported products is crucial. Continued research and vigilance will be essential in combating the spread of antibiotic resistance and ensuring the safety of our food supply.