Association of Toxin-Producing Clostridium botulinum with the Macroalga Cladophora in the Great Lakes

BioTechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States.
Environmental Science & Technology (Impact Factor: 5.33). 03/2013; 47(6). DOI: 10.1021/es304743m
Source: PubMed


Avian botulism, a paralytic disease of birds, often occurs on a yearly cycle and is increasingly becoming more common in the Great Lakes. Outbreaks are caused by bird ingestion of neurotoxins produced by Clostridium botulinum, a spore-forming, gram-positive, anaerobe. The nuisance, macrophytic, green alga Cladophora (Chlorophyta; mostly Cladophora glomerata L.) is a potential habitat for the growth of C. botulinum. A high incidence of botulism in shoreline birds at Sleeping Bear Dunes National Lakeshore (SLBE) in Lake Michigan coincides with increasingly massive accumulations of Cladophora in nearshore waters. In this study, free-floating algal mats were collected from SLBE and other shorelines of the Great Lakes between June and October 2011. The abundance of C. botulinum in algal mats was quantified and the type of botulism neurotoxin (bont) genes associated with this organism were determined by using most-probable-number PCR (MPN-PCR) and five distinct bont gene-specific primers (A, B, C, E, and F). The MPN-PCR results showed that 16 of 22 (73%) algal mats from the SLBE and 23 of 31(74%) algal mats from other shorelines of the Great Lakes contained the bont type E (bont/E) gene. C. botulinum was present up to 15 000 MPN per gram dried algae based on gene copies of bont/E. In addition, genes for bont/A and bont/B, which are commonly associated with human diseases, were detected in a few algal samples. Moreover, C. botulinum was present as vegetative cells rather than as dormant spores in Cladophora mats. Mouse toxin assays done using supernatants from enrichment of Cladophora containing high densities of C. botulinum (>1000 MPN/g dried algae) showed that Cladophora-borne C. botulinum were toxin-producing species (BoNT/E). Our results indicate that Cladophora provides a habitat for C. botulinum, warranting additional studies to better understand the relationship between this bacterium and the alga, and how this interaction potentially contributes to botulism outbreaks in birds.

Download full-text


Available from: Chan Lan Chun, May 20, 2014
1 Follower
87 Reads
  • Source
    • "Les moules zébrées peuvent jouer un rôle supplémentaire à celui de porteur en créant des conditions favorables aux spores via les déchets qu'elles produi‐ sent. Les cladophores contiennent une quantité élevée de C. botulinum (entre 1 et 10 000 NPP par gramme d'algues sèches selon la mé‐ thode de dénombrement du nombre le plus probable (NPP)) et constituent donc une source de C. botulinum de type E. C. botulinum est présent dans les algues à la fois sous forme végétative et sous forme de spores [3] [6]. La prévention et la gestion des épisodes restent délicates. "

  • Source
    • "Such an approach has recently been successfully used to develop a mostprobable-number PCR (MPN PCR) method to detect type E C. botulinum in samples collected from beaches on Lakes Michigan and Ontario and to demonstrate the presence of vegetative cells and not spore cells. In this study, all heattreated samples were negative for the bont/E gene whereas they were positive without heat treatment after enrichment, demonstrating that only viable cells were detected by PCR despite the presence of a small number of dead cells in the enrichment (Chun et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Between 2011 and 2013, 17 poultry botulism outbreaks were investigated in France. All cases were associated with C. botulinum type C-D. Presence of C. botulinum was studied in 7 areas: poultry house, changing room, ventilation system, surroundings, animal reservoirs, water and feed. Swabs, litter, soil, darkling beetles, rodents and wild bird droppings, feed and water samples were collected. The presence of C. botulinum type C-D in the environment of affected flocks was detected in 39.5% of the 185 samples analyzed by real-time PCR. C. botulinum type C-D was reported in each area. Four areas were more frequently contaminated, being found positive in more than half of farms: darkling beetles (9/11), poultry house (14/17), water (13/16) and surroundings (11/16). After cleaning and disinfection, the ventilation system and/or the soil (in the houses and the surroundings) returned positive results in 4 out of 8 poultry farms. Consequently, darkling beetles, the drinking water, the ventilation system and the soil in the surroundings and the houses were identified as the main critical contaminated areas to consider in poultry farms to prevent recurrence of botulism outbreaks.
    Avian Pathology 08/2014; 43(5):1-22. DOI:10.1080/03079457.2014.957644 · 1.64 Impact Factor
  • Source
    • "However, bird botulism has been reported in ponds on the shores of Neusiedler See (Zechmeister et al., 2005). In Spain, inland wetlands are more often troubled by bird botulism (Vidal et al., 2013) than coastal wetlands with a tidal regime (Contreras de Vera et al., 1991). This is probably due to both the water movement and the salt concentration. "
    [Show abstract] [Hide abstract]
    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.
    Frontiers in Microbiology 06/2014; 5:287. DOI:10.3389/fmicb.2014.00287 · 3.99 Impact Factor
Show more