Listeria-busting discovery could be adapted for processing plants

10 Jan 2012

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Research that may lead to a human drug to combat Listeria monocytogenes could also be adapted to fight the deadly bug in food processing plants, said the team leader behind the breakthrough.

Scientists from Cornell University have discovered a compound that stops Listeria from transforming itself from a harmless microbe into a potentially lethal human pathogen. They said Listeriosis – the disease caused by the bacteria – is responsible for 10% of all deaths in the US from foodborne diseases.

The substance called fluoro-phenyl-styrene-sulfonamide (FPSS) hinders the bacteria’s ability to survive a raft of ‘environmental assaults’ thrown at it from rapid changes in temperatures during food production and storage to highly acidic stomach conditions and osmotic and anaerobic states in the small intestines, said Professor Kathryn Boor.

The team from Cornell found Listeria has developed an anti-stress capacity called sigma B after robotically screening 57,000 natural and synthetic small compounds held in the libraries of other research institutes.

This ‘stress responsive alternative factor’ controls more than 150 genes which are key in its capabilities connected to factors such as virulence and survival in hosts.

The research, published in mBio, a journal of the American Society for Microbiology, could lead to the development of a human drug to fight against Listeria and other bacterial infections.

Food plant application?

While the team had focused on the ability of FPPS to tackle Listeria in the human gut, Prof Boor said the same discovery could, in principle, be applied in a food processing environment.

‘It is reasonable to hypothesize that treatment of surfaces with FPSS could make Listeria monocytogenes that might contaminate such a treated surface easier to kill, as the organism would be likely to be impaired in its ability to respond to environmental stresses, such as treatment with sanitizers,’ she said.

Prof Boor said the project was part of a ‘newly emerging approach in the search for antibiotics that are not dangerous to mammals but stop such pathogens as Listeria, and could be a possible treatment against other organisms’.

She added that further research was needed to better understand how FSPP controls sigma B activity and whether the compound affects the same mechanism in such pathogens as B. cereus (foodborne illness), Staphylococcus aureus (cause of acne and pneumonia) and Bacillus anthracis (anthrax).

Source: mBio