Overview of botulinum neurotoxin-producing clostridia in soils in France

Botulism is a flaccid paralysis disease caused by one of the seven neuroparalytic toxins produced by anaerobic spore-forming clostridia. While soil is reported in the literature as being an important reservoir of clostridia capable of producing botulinum neurotoxins, no study has been conducted in France up to now to establish its prevalence and study soil factors influencing its occurrence. The significance of our research is in providing a global picture of the unequal distribution of botulinum neurotoxin-producing clostridia and detected subtypes countrywide, showing that types involved in human botulism outbreaks are commonly detected, while those involved in animal outbreaks are rare. Finally, the stability of spores was evaluated. Results showed a high persistence of spores under tested conditions. This study provides new data regarding the distribution of botulinum neurotoxin-producing clostridia in soils that are crucial for a better understanding and management of animal and human botulism outbreaks.