Antibiotic resistant bacteria in agricultural soils could spread into the food chain, according to some research findings, and experts have warned that this environmental threat is being given too little attention. New research is aiming to improve understanding in this area and assess the threat.

In February, researchers at Newcastle University warned that policy makers risk ‘losing the fight’ against antibiotic resistance, unless they tackle the problem of resistance on all fronts, and claimed resistant genes, which could eventually make bacteria impossible to treat with even last resort medicines, are freely crossing environmental, agricultural and clinical boundaries.

The Newcastle experts had examined soil samples dating back to 1923 and found a parallel between the appearance of antibiotic resistant bacteria in medicine and similar resistant microorganisms in agricultural soils treated with animal manure. They said their findings indicated that using manure and antibiotic substitutes could allow soil bacteria to acquire resistance genes to new antibiotics and recommended “reducing antibiotic use across all sectors if we are to reduce global antibiotic resistance.”

Now, new research at the University of Southampton is to investigate this source of antibiotic resistance, and whether the bacteria pose a threat to humans through the food chain.

Researchers said they will look into how AMR is introduced into natural soil bacteria, whether through applications of manure from treated animals, or from droppings of domestic or wild animals and birds, and will inform the government’s strategy for dealing with the threat of resistance. The work is being funded by the Natural Environment Research Council (NERC).

Professor Bill Keevil and Dr Marc Dumont from the University’s Network on Antimicrobial Resistance and Infection Prevention (NAMRIP) are leading the study. Professor Keevil said, “The project addresses if antibiotic resistant bacteria introduced by agricultural practice (animal husbandry, human wastewater disposal, improperly composted manures) or domesticated and wild animal faecal droppings contribute antibiotic resistance genes to the soil microbiome communities or gain resistance genes from the soil antibiotic resistance gene pool (the ‘resistome’), becoming more difficult to treat if they are spread in the food chain causing disease.”

As part of the project, scientists will take clay, loam and sandy soils obtained from different parts of the country for analysis of their natural antibiotic resistant species before adding important antibiotic resistant or sensitive bacteria to monitor antibiotic resistance transfer.

Published last week, the government’s O’Neill Review on antimicrobial resistance warned that, if left unchecked, antibiotic resistant bacteria will kill more people than cancer, claiming a life every three seconds by 2050. They called for a raft of measures to avert this scenario, including incentives for research into developing new antibiotics, reducing the use of antibiotics on livestock and banning the use of last resort treatments in animal agriculture.