Vegetables could be transmitting antibiotic-resistant bacteria to humans

25 Jun 2019

Image: Digifuture

It is estimated that of the 2m antibiotic-resistant infections reported each year in the US, 20pc are linked to agriculture.

As anxiety about the impending post-antibiotic era has intensified over the last few years, many have suggested turning to a plant-based diet to minimise our exposure to meat laden with antibiotics and antibiotic-resistant bacteria.

Now, it looks like things may not be that simple. While going vegan or vegetarian could benefit you in a number of other ways, it can no longer guarantee you won’t be exposed to the antibiotic-resistant bacteria that can be found in meat.

At ASM Microbe, the annual meeting of the American Society for Microbiology held in San Francisco each year, researchers presented findings suggesting that plant foods can serve as vehicles for transmitting antibiotic resistance to the gut microbiome.

The US Centers for Disease Control and Prevention estimated that of the 2m antibiotic-resistant infections reported each year in the US, 20pc are linked to agriculture. Until now, little had been done to determine how eating plants contributes to the spread of antibiotic-resistant ‘superbugs’.

Lead author on the study presented at ASM Microbe, Marlène Maeusli, said that the findings “highlight the importance of tackling foodborne antibiotic resistance from a complete food chain perspective that includes plant foods in addition to meat”.

Mauesli, a PhD candidate at the Keck School of Medicine at the University of Southern California, explained that in order to replicate the silent, asymptomatic colonisation of bacteria that occurs in the gut after consumption (which does not result in immediate illness), her team grew lettuce and exposed it to antibiotic-resistant E coli, before feeding it to mice and analysing their faecal samples over time.

“We mimicked antibiotic and antacid treatments, as both could affect the ability of superbugs to survive passage from the stomach to the intestines.”

EurekAlert reported: “Exposure to one type of antibiotic did not increase the ability of superbugs to hide in the mouse intestines, whereas a second antibiotic resulted in stable gut colonisation after ingestion. Ingestion of bacteria with food also changed colonisation, as did administering antacid before ingesting bacteria.”

The research team is still seeking out the plant characteristics and the host factors that result in key microbial community shifts in the gut, both those that put us at risk for colonisation and those that prevent it.

Mauesli concluded: “The environment and human health – in this context via agriculture and microbiomes – are inextricably linked.”

Lettuce growing in the ground. Image: Digifuture/Depositphotos

Kelly Earley was a journalist with Silicon Republic