Scientists Create Medical And Food Safety Tool From Virus

Professor Mike Gasson from the Institute of Food Research in Norwich discovered the potential of viruses while researching flavour development in cheese in the early 1990s. And with the help of Profos AG, an international company specialising in bacterial viruses and antimicrobial agents, and PBL, technology transfer experts on the Norwich Research Park, the germ of an idea is translating into practical technology. A new, exclusive worldwide licence marks a first step towards commercialisation.

"Viruses can infect bacteria as well as humans. A virus invades bacterial cells, multiplies and then produces an enzyme to burst the cell wall, enabling it to escape and infect more cells," says Professor Gasson. "We targeted an enzyme with this fire-power, to develop its potential in combating pathogenic bacteria."

Viruses that infect bacteria are called bacteriophages. The bacteria-bursting enzymes that caught Gasson's attention are called lysins. Different lysins attack specific bacteria, so could be used as a diagnostic tool as well as an antimicrobial therapy in people and animals. The bacteriophage lysins covered in the licence can be used to detect or selectively kill Listeria and Clostridium. They could even provide an alternative to antibiotics in some applications.

Rapid detection is particularly important for some of the more virulent bacteria, such as Listeria monocytogenes. Listeria exists naturally in the soil and general environment, but in some soft mould-ripened cheeses and pâtés can be present in higher numbers. The elderly, pregnant women and babies are most vulnerable, which is why pregnant women are advised against eating soft, mould-ripened cheeses such as Brie, Camembert and blue-veined varieties.

When listeriosis takes hold, it is often severe and life-threatening. The United States government operates a zero tolerance policy of Listeria in food. But there is no other simple rapid test available for large scale use by food manufacturers.

"Listeria is the food industry's nightmare. Professor Gasson had the vision to spot the potential of using a virus to destroy it. With the expertise at Profos we're turning that investigative science into a significant food safety tool to benefit the public," says Jan Chojecki, Managing Director of PBL.

The licence also covers lysins that destroy Clostridium. This bacteria forms hardy spores, resistant to heating and drying. In poultry, Clostridium perfringens causes necrotic enteritis, currently cured with antibiotics. In humans, Clostridium difficile causes diarrhoea in patients receiving antibiotic treatment - the bacterium seizes the opportunity to infect provided by disruption to naturally-occurring bacteria of the bowel.

"The demand for commercial alternatives to antibiotics is growing, in response to the need to tackle bacterial antibiotic resistance. As well as providing a new tool to combat bacteria now, there is interest in developing bacteriophage lysins to replace antibiotics in some applications in the future. Unlike antibiotics, this technology provides a precision tool, designed to kill specific bacteria while leaving other micro-organisms intact," says Professor Gasson.