Meet the cultured solution for food-borne superbugs

Bacterial food contamination can wreak havoc on the digestive system, with E. coli and Salmonella pathogens particularly capable of causing a range of complications including, in some cases, death.

And with antibiotic resistance growing among pathogens, medicine is rapidly searching for new ways to beat back superbugs.

Researchers at the University of Connecticut (US) have found a potential candidate to combat food-borne illnesses: other bacteria.

Dr Dennis D’Amico and his team at UConn’s College of Agriculture have tested the ability of two Salmonella variations against a commensal bacteria called Hafnia alvei B16. Commensal bacterial cultures are found in the human microbiome and are considered ‘good’ bacteria which provide the body protection against bad pathogens.

The variation studied by D’Amico’s team are known to cause salmonella outbreaks in food.

They’re also increasingly antibiotic resistant.

“One of the biggest challenges in food safety, just like in human medicine, is this emergence of superbugs,” D’Amico says.

“And these particular strains, as with a lot of Salmonella, have developed resistance to most of the antibiotics we use in food production and human medicine, so we wanted to focus on them as a target.”

Using bacterial cultures against bacteria may seem counterintuitive, but a tiny percentage of bacterial species on Earth are capable of infecting and harming humans. Over 99% are either beneficial or harmless.

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D’Amico explains that cultures of protective bacteria and interact with other species to generate metabolic substances which have antimicrobial properties.

In the presence of these metabolites, a pathogen can effective shut itself down to prolong its survival. In doing so, these cultures can render the negative effects of bad bacteria obsolete.

“What we learned from our previous work is that not only can these protective cultures stop the growth of pathogens in different situations … but they also had these impacts on the virulence of those pathogens when they were able to grow,” D’Amico says.

Although metabolic compounds are capable of switching off pathogen functions, the entire presence of the H. alvei B16 bacterium relative to E. coli or Salmonella pathogens was found to reduce the chances of infection by over 90 percent, according to the research.

This, D’Amico believes, may be the result of the B16 culture prompting nearby intestinal cells to fortify themselves against pathogens.

“Because the Salmonella could still adhere to, but not invade intestinal cells, this culture could potentially have stimulated those cells to protect themselves against the invading pathogen, so that could be another mechanism by which these protective cultures exert an effect,” he says.