Botulism outbreaks in natural environments – an update

Abstract

Clostridium botulinum comprises a diverse group of botulinum toxin-producing anaerobic rod-shaped spore-forming bacteria that are ubiquitously distributed in soils and aquatic sediments. Decomposition of plants, algae, and animals creates anaerobic environments that facilitate growth of C. botulinum, which may then enter into food webs leading to intoxication of animals. Via saprophytic utilization of nutrients, the bacteria rapidly sporulate, creating a reservoir of highly robust spores. In the present review, we focus on the occurrence of C. botulinum in non-clinical environments, and examine factors influencing growth and environmental factors associated with botulism outbreaks. We also outline cases involving specific environments and their biota. In wetlands, it has been found that some C. botulinum strains can associate with toxin-unaffected organisms–-including algae, plants, and invertebrates–-in which the bacteria appear to germinate and stay in the vegetative form for longer periods of time. We suggest the need for future investigations to resolve issues related to the environments in which C. botulinum spores may accumulate and germinate, and where the vegetative forms may multiply.

The Exosporium Layer of Bacterial Spores: a Connection to the Environment and the Infected Host

“…Botulism results from exposure to a potent neurotoxin produced by the spore-forming bacterium Clostridium botulinum (22)(23)(24). There are five main kinds of botulism.…”

A review of the abundance, behaviour and detection of clostridial pathogens in agricultural soils

“…Some BTPC toxinotypes are endemic to geographical areas or environments. Based on the literature, toxin type A is frequently isolated in North American soils west of the Mississippi River and in uncultivated soils, whereas type B prevails in soils to the east of the Mississippi, European soils and cultivated soils (Haagsma, ; Dodds, ; Espelund & Klaveness, ). Types C, D, G and C/D mosaic strains are also common in European soils, with C, D and C/D strains frequently associated with environmental botulism outbreaks.…”

“…Types C, D, G and C/D mosaic strains are also common in European soils, with C, D and C/D strains frequently associated with environmental botulism outbreaks. Type E is commonly isolated from marine environments, such as fish gut contents and coastal sediments, with research indicating this toxinotype has a higher affinity for permanently wet environments (Haagsma, ; Espelund & Klaveness, ). Lúquez et al () identified BTPC in 23.5% of 2009 Argentinean soil samples, which is high compared to the 5.7% and 16.5% prevalence found in British (Smith & Young, ) and Japanese soils (Yamakawa et al, ), respectively.…”

“…For example, despite highly effective vaccination programmes, tetanus ( C. tetani ) caused over 10 000 confirmed deaths in 2015 alone (World Health Organisation, ), and C. perfringens is a leading cause of gastroenteritis in both the UK and the USA. Other significant clostridial diseases include botulism ( C. botulinum , C. baratii and C. butyricum ) (Fach et al, ; Espelund & Klaveness, ) and various gangrenous and necrotic diseases ( C. perfringens , C. novyi , C. septicum and C. chauvoei ) (Sasaki et al, ; Brynestad & Granum, ; Lindström et al, ; Skarin & Segerman, ). The formerly‐assigned Clostridium species, Clostridioides difficile , Paeniclostridium sordellii and Paraclostridium bifermentans , are genetically and phenotypically akin to Clostridium sensu stricto species, and, due to their significant role in disease mediation, will also be discussed within this review.…”

Surviving Between Hosts: Sporulation and Transmission

“…C. perfringens has been reported in wastewater treatment systems and can be isolated from animal intestinal tracks (5, 203). C. botulinum spores are found in animal carcasses and even algal mats, where accumulation of botulinum toxin is central to human disease occurrence (204). Multiple strains of C. difficile , including those associated with disease and those less commonly found in patients, have been isolated from water and sediments.…”