New Source of World’s Deadliest Toxin Discovered

Quadram Institute scientists have identified genes encoding a previously undiscovered version of the botulinum neurotoxin in bacteria from a cow’s gut.

This is the first time that an intact cluster of genes for making botulinum neurotoxin have been found outside of the bacterium Clostridium botulinum or its close relatives and only the second report of a new botulinum toxin in the past 40 years.

Clostridium botulinum, a dangerous pathogen when ingested, is also used in a range of medical procedures, as well as for cosmetic purposes. The discovery of this new type of botulinum neurotoxin, therefore holds potential for development opportunities.

Dr Jason Brunt and Dr Andrew Carter, working with Professor Mike Peck and Dr Sandra Stringer, screened the National Centre for Biotechnology Information’s Whole Genome Sequence database, for other entries that were similar to the predicted proteins that the botulinum toxin gene would produce. This search identified a previously undiscovered gene cluster encoding a new botulinum neurotoxin and accessory proteins in the genome of a species of Enterococcus bacteria that had been isolated from cow faeces from stock in the USA.

“Once expressed as a protein, this new neurotoxin may possess novel properties, such as immunomodulatory properties making it useful for a very wide range of medical problems. It may also have properties that make it an ideal candidate for use as an alternative to existing botulinum neurotoxins such as Botox®” said Dr Jason Brunt.

“It is an intriguing question as to how this Enterococcus strain acquired a botulinum neurotoxin gene cluster, what benefit it brings to this bacterium and further work is required to explore the implications of our important finding with regard to the possibility of its transfer between bacteria. Further work is also required to characterise this novel toxin, but initial indications are that this may be a highly significant discovery. We will now determine the potency of this new botulinum toxin and how it may be used as a therapeutic agent” said Dr Andrew Carter.

The study was funded by the Biotechnology and Biological Sciences Research Council.

Reference: Identification of a novel botulinum neurotoxin gene cluster in Enterococcus, Jason Brunt, Andrew T. Carter, Sandra C. Stringer, Michael W. Peck FEBS Letters (2018) DOI:10.1002/1873-3468.12969