Persistence of Bacillus thuringiensis subsp. kurstaki in Urban Environments following Spraying

Cuyk, Sheila Van; Deshpande, Alina; Hollander, Attelia; Duval, Nathan; Ticknor, Lawrence O.; Layshock, Julie; Gallegos-Graves, Laverne; Omberg, Kristin M.

doi:10.1128/aem.05207-11

Cited by 32 publications

(17 citation statements)

References 34 publications

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“…In spite of the immense exploitation of B. thuringiensis as a biopesticide, few evaluations of its dispersal and persistence following aerosol application have been reported (19)(20)(21)(22). More recently, evaluations of this organism specifically as a spore surrogate (23)(24)(25) and also as released in dry (26) and wet (27) aerosols have been reported.…”

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confidence: 99%

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Bishop

Stapleton

2016

Appl Environ Microbiol

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Spores of an acrystalliferous derivative of Bacillus thuringiensis subsp. kurstaki, termed Btcry؊, are morphologically, aerodynamically, and structurally indistinguishable from Bacillus anthracis spores. Btcry؊ spores were dispersed in a large, openended barn together with spores of Bacillus atrophaeus subsp. globigii, a historically used surrogate for Bacillus anthracis. Spore suspensions (2 ؋ 10 12 CFU each of B. atrophaeus subsp. globigii and Btcry؊) were aerosolized in each of five spray events using a backpack misting device incorporating an air blower; a wind of 4.9 to 7.6 m s ؊1 was also flowing through the barn in the same direction. Filter air samplers were situated throughout the barn to assess the aerosol density of the spores during each release. Trays filled with a surfactant in aqueous buffer were placed on the floor near the filter samplers to assess spore deposition. Spores were also recovered from arrays of solid surfaces (concrete, aluminum, and plywood) that had been laid on the floor and set up as a wall at the end of the barn. B. atrophaeus subsp. globigii spores were found to remain airborne for significantly longer periods, and to be deposited on horizontal surfaces at lower densities, than Btcry؊ spores, particularly near the spray source. There was a 6-fold-higher deposition of Btcry؊ spores than of B. atrophaeus subsp. globigii spores on vertical surfaces relative to the surrounding airborne density. This work is relevant for selecting the best B. anthracis surrogate for the prediction of human exposure, hazard assessment, and hazard management following a malicious release of B. anthracis. IMPORTANCEThere is concern that pathogenic bacteria could be maliciously disseminated in the air to cause human infection and disruption of normal life. The threat from spore-forming organisms, such as the causative agent of anthrax, is particularly serious. In order to assess the extent of this risk, it is important to have a surrogate organism that can be used to replicate the dispersal characteristics of the threat agent accurately. This work compares the aerosol dispersal and deposition behaviors of the surrogates Btcry؊ and B. atrophaeus subsp. globigii. Btcry؊ spores remained in the air for a shorter time, and were markedly more likely to adhere to vertical surfaces, than B. atrophaeus subsp. globigii spores. Bacillus anthracis is an important bacterial agent of concern (1). It is pathogenic to humans, particularly by inhalational exposure (2). The organism's endospores manifest greater environmental persistence and higher resistance to chemical decontaminants than those of other bacteria. Understanding of the threat posed by malicious use of B. anthracis and the development of effective countermeasures require a comparable, nonpathogenic surrogate. Bacillus atrophaeus subsp. globigii has, for many decades, been a B. anthracis surrogate (3). B. atrophaeus subsp. globigii and other surrogates related to Bacillus subtilis have generated useful information regarding spore dispersal (4, 5)....

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Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Bishop

Stapleton

2016

Appl Environ Microbiol

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“…The modes of action of some B. thuringiensis subspecies together with their fate in the environment have been largely studied (6,30,45). B. thuringiensis is a natural larval pathogen (bacterium) that produces a toxic crystal during its sporulation (34), and its fate in the field can be monitored by using three different approaches.…”

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Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

Tetreau

Alessi

Veyrenc

et al. 2012

Appl Environ Microbiol

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Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores. In the present article, we show that the high concentration of toxins found in these litters is consistent with spore recycling in the field, which gave rise to the production of new crystal toxins. Furthermore, in these toxic leaf litter samples, Cry4Aa and Cry4Ba toxins became the major toxins instead of Cyt1Aa in the commercial mixture. In a microcosm experiment performed in the laboratory, we also demonstrated that the toxins, when added in their crystal form to nontoxic leaf litter, exhibited patterns of differential persistence consistent with the proportions of toxins observed in the field-collected toxic leaf litter samples (Cry4 > Cry11 > Cyt). These results give strong evidence that B. thuringiensis subsp. israelensis recycled in specific breeding sites containing leaf litters, and one would be justified in asking whether mosquitoes can become resistant when exposed to field-persistent B. thuringiensis subsp. israelensis for several generations.

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“…Only incomplete and contradictory data are available about the Bacillus spp. persistence in seawater (Menon and de Mestral, 1985;Surgeoner and Farkas, 1990;Tilquin et al, 2008;Van Cuyk et al, 2011).…”

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confidence: 99%

Eco-physiological response of two marine bivalves to acute exposition to commercial Bt-based pesticide

Manachini

Arizza

Rinaldi

et al. 2013

Marine Environmental Research

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a b s t r a c tMicrobial products based on the entomopathogenic bacterium Bacillus thuringiensis (Bt) are among the most common biopesticides used worldwide to suppress insect pests in forests, horticulture and agricultural crops. Some of the effects of commercial Bt have been recorded for terrestrial and freshwater non-target organisms but little research is available on marine fauna. Nevertheless, due to the contiguity of agro-ecosystems and coastal habitats, marine fauna may be highly influenced by this control method. We studied the effect of a commercial Bt product on the physiological and ecological responses and the energy budget of two of the most frequent marine intertidal bivalves in the Mediterranean, the native Mytilaster minimus and the invasive Brachidontes pharaonis. To test the effects experimentally, we simulated the worst scenarios possible using the average dose applied to fields and a hypothetical accumulation dose. The results showed the feeding rates of both species were affected detrimentally by the different experimental conditions; higher concentrations led to higher respiration rates, however neither species showed any significant difference in excretion rates. The biopesticide had a significant effect on the energy budget, the values decreasing with doses. In addition, it led to high mortality for the worst treatments and, in both species, induced significantly higher cardiac activity than in the controls. These results indicate a measurable effect of Bt commercial products on marine organisms, and great attention should be paid to biopesticides composed by entomopathogenic bacteria and addictive compounds. In addition, the results highlight the urgent need to study not only the effects of anthropogenic pressures on target organisms but also to extend our view to other ecosystems not expected to be influenced. Gaining data at the organismal level should help increase the sustainability of pest control and reduce the consequences of side-effects.

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Persistence of Bacillus thuringiensis subsp. kurstaki in Urban Environments following Spraying

Cited by 32 publications

References 34 publications

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

Eco-physiological response of two marine bivalves to acute exposition to commercial Bt-based pesticide

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