Imported Seafood Linked to Deadly Colistin Resistance Genes

Research from the University of Georgia has revealed alarming findings about colistin-resistance genes in imported seafood, specifically shrimp and scallops sold in markets in Atlanta. This discovery raises significant concerns regarding the efficacy of colistin, a vital last-resort antibiotic, as rising bacterial resistance threatens its effectiveness.

Colistin exists in two primary forms: colistimethate sodium, which can be injected or inhaled, and colistin sulfate, typically applied topically or taken orally. Microbiologists fear that increasing bacterial resistance is undermining the power of this crucial antibiotic. The research team identified colistin-resistance genes in bacteria sourced from imported seafood, highlighting a potential pathway for the spread of these dangerous genes.

Understanding the Resistance Mechanism

The resistance genes, known as mcr genes, have been identified since their first isolation in 2016 from imported seafood. These genes can move between bacteria via plasmids, effectively transforming previously treatable infections into serious health threats. The research indicates that approximately 90% of the shrimp consumed in the U.S. is imported, amplifying the risk of disseminating colistin resistance.

The predominant bacteria in imported shrimp are Gram-negative organisms, primarily from the genus Serratia spp. and Aeromonas spp.. The existence of the mcr gene has been documented in bacteria isolated from seafood originating from various exporting countries, suggesting that aquaculture practices may be a significant source of this resistance.

The researchers emphasized the interconnectedness of the 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 highlights the urgent need for enhanced monitoring systems and international collaboration to address antimicrobial resistance effectively.

Implications for Public Health

The findings illustrate the potential hazards associated with imported seafood and the need for stringent surveillance measures. As colistin is also employed in agriculture to treat infections and promote growth, the implications for both human and animal health are considerable. Addressing this issue is critical, especially given the role of antibiotics in maintaining health standards in both fields.

These findings have been documented in the journal mSphere, under the title “Introduction of the transmissible mobile colistin resistance genes mcr-3 and mcr-9 to the USA via imported seafood.”

In related developments, researchers have also discovered a new class of antibiotics that target Neisseria gonorrhoeae, the bacterium responsible for gonorrhea. This novel approach triggers a self-destruction program in these pathogens, including multi-resistant varieties, further emphasizing the ongoing battle against antibiotic resistance.

As the global community grapples with these challenges, public awareness and policy adjustments will be crucial in mitigating the risks associated with antibiotic resistance from food sources.