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, an international company specialising in bacterial viruses and antimicrobial agents, and PBL, technology transfer experts on the Norwich Research Park, Gasson was able to develop a practical technique.
"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," said 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.
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 industry1s nightmare. Professor Gasson had the vision to spot the potential of using a virus to destroy it. With the expertise at Profos we1re turning that investigative science into a significant food safety tool to benefit the public," said PBL managing director Jan Chojecki.
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," said Gasson.
The mission of the Institute of Food Research is to carry out independent basic, and strategic research on food safety, quality, nutrition and health. It is a company limited by guarantee, with charitable status, grant aided by the Biotechnology and Biological Sciences Research Council (BBSRC).