UK Edition
Fish supper may carry risk of drug-resistant superbugs
A plate of fish and chips is increasingly likely to expose people to untreatable bacteria because of the spread of superbugs at sea, new research has found.
A study of dolphins revealed a surge in antibiotic-resistant bugs that are dangerous to humans in the marine environment in just a handful of years.
While the mammals themselves are eaten in very few parts of the world, they are considered a good indicator for the safety of sea life that does end up as food.
Investigators at Florida Atlantic University periodically captured, swabbed then released Bottlenose dolphins from 2003 to 2015 in the Indian River Lagoon on the US Atlantic Coast.
They found that between 2009 and 2015 resistance to common antibiotics in various strains of E. coli more than doubled.
Meanwhile the resistance to drugs of a pathogen called Vibrio alginolyticus, known to cause serious seafood poisoning, also showed a significant increase.
Scientists also found evidence of resistant Acinetobacter baumannii, which is traditionally the cause of serious hospital-acquired infections.
Published in the journal Aquatic Mammals, the findings raise the prospect that diners of raw or undercooked fish could fall ill with bugs for which there are no useful medicines.
It comes days after Public Health England revealed there have been 19 new drug-resistant types of bacteria discovered in the UK over the past 10 years.
Antimicrobial resistance (AMR) is one of the gravest public health emergencies facing the world, threatening to make common infections deadly for the first time in almost a century.
AMR occurs when the DNA of bacteria mutates, or where different types of bacteria acquire DNA off each other, rendering antibiotics ineffective.
It has been driven by profligate use of antibiotics in both human and animal health and by the fact that no new classes of the drugs have been developed in decades.
PHE estimates that roughly 5,000 people die due to the problem in Britain each year.
Adam Schaefer, who led the new research, said: “We have been tracking changes over time and have found a significant increase in antibiotic resistance in isolates from these animals.
“This trend mirrors reports from human health care settings.
“Based on our findings, it is likely that these isolates from dolphins originated from a source where antibiotics are regularly used, potentially entering the marine environment through human activities or discharges from terrestrial sources."
Over 13 years the Florida team collected samples containing 733 pathogen isolates from 171 different Bottlenose dolphins.
Eighty-eight per cent of these isolates were resistant to at least one antibiotic.
The most common resistance - found in 91.6 per cent - was to erythromycin.
Dr Peter McCarthy, co-author, described the drug resistance found in the Indian River Lagoon, which is good model marine environments comparably close to dense human habitation, as a “significant public health concern.
"The nationwide human health impact of the pathogen Acinetobacter baumannii is of substantial concern as it is a significant nosocomial [originating in hospital] pathogen with increasing infection rates over the past 10 years.” he said.
"In addition to nosocomial infections, resistant strains associated with fish and fish farming have been reported globally.”
Global health chiefs are currently warning that increasing numbers of tuberculosis strains are becoming resistant to antibiotics.
The were nearly 5,000 cases of TB in the UK last year.