Population structure and toxin gene profiles of Bacillus cereus sensu lato isolated from flour products

2019 ◽  
Vol 366 (20) ◽  
Author(s):  
Patrick Kindle ◽  
Danai Etter ◽  
Roger Stephan ◽  
Sophia Johler
Keyword(s):  
Risk Assessment ◽  
Population Structure ◽  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Toxin Gene ◽  
Type Iii ◽  
Gene Profiles ◽  
Enterotoxin Genes ◽  
Parasporal Crystals ◽  
Bacillus Cereus Sensu Lato

ABSTRACT Data on the occurrence, population structure and toxinogenic potential of Bacillus cereus sensu lato isolated from flour is essential to enable improved risk assessment. We aimed to provide data on the occurrence of B. cereus sensu lato in flour products at retail level. In addition, we screened the isolates for Bacillus thuringiensis and Bacillus cytotoxicus and determined population structure and toxin gene profiles. We screened 89 flour products for presence of B. cereus sensu lato, resulting in 75 positive samples (84%). We were able to show that the population structure of members of the B. cereus group isolated from flour is highly diverse. Isolates were assigned to panC types II (4%), III (21%), IV (39%) and V (36%). Production of parasporal crystals characteristic for Bacillus thuringiensis was detected in seven isolates assigned to panC type III, IV and V. No B. cytotoxicus were detected. Two of the isolates harbored ces encoding cereulide, which causes the emetic syndrome. Various enterotoxin genes were found, with all isolates harboring nhe, 75% of isolates harboring hbl and 51% of the isolates harboring cytK-2. Our findings suggest that toxinogenic B. cereus sensu lato are common in flour products at retail level.

Occurrence of Toxigenic Bacillus cereus and Bacillus thuringiensis in Doenjang, a Korean Fermented Soybean Paste

2016 ◽  
Vol 79 (4) ◽  
pp. 605-612 ◽  
Author(s):  
KYUNG MIN PARK ◽  
HYUN JUNG KIM ◽  
MOON CHEOL JEONG ◽  
MINSEON KOO
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Detection Rate ◽  
Fermented Soybean ◽  
Toxin Genes ◽  
Soybean Paste ◽  
Enterotoxin Genes ◽  
Soybean Food

ABSTRACT This study determined the prevalence and toxin profile of Bacillus cereus and Bacillus thuringiensis in doenjang, a fermented soybean food, made using both traditional and commercial methods. The 51 doenjang samples tested were broadly contaminated with B. cereus; in contrast, only one sample was positive for B. thuringiensis. All B. cereus isolates from doenjang were positive for diarrheal toxin genes. The frequencies of nheABC and hblACD in traditional samples were 22.7 and 0%, respectively, whereas 5.1 and 5.1% of B. cereus isolates from commercial samples possessed nheABC and hblACD, respectively. The detection rate of ces gene was 10.8%. The predominant toxin profile among isolates from enterotoxigenic B. cereus in doenjang was profile 4 (entFM-bceT-cytK). The major enterotoxin genes in emetic B. cereus were cytK, entFM, and nheA genes. The B. thuringiensis isolate was of the diarrheagenic type. These results provide a better understanding of the epidemiology of the enterotoxigenic and emetic B. cereus groups in Korean fermented soybean products.

scholarly journals Adaptation of Bacillus thuringiensis to plant colonisation affects differentiation and toxicity

2020 ◽  
Author(s):  
Yicen Lin ◽  
Monica Alstrup ◽  
Janet Ka Yan Pang ◽  
Gergely Maróti ◽  
Mériem Er-Rafik ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Single Cells ◽  
Toxin Production ◽  
Causative Mutation ◽  
Insect Larvae ◽  
Transcription Terminator ◽  
Fitness Advantage ◽  
Two Populations ◽  
Bacillus Cereus Sensu Lato

AbstractAlthough certain isolates from the Bacillus cereus group (Bacillus cereus sensu lato) are used as probiotics, safety concerns remain due to pathogenic traits. For example, toxin production might shift as an adaptive survival strategy in natural niches (the soil and plant rhizosphere). Therefore, it is crucial to explore bacterial evolutionary adaptation to the environment. Herein, we investigated Bacillus thuringiensis (Cry-) adaptation to the colonisation of Arabidopsis thaliana roots, and monitored changes in cellular differentiation in experimentally evolved isolates. Isolates from two populations displayed improved iterative ecesis on roots and increased toxicity against insect larvae. Molecular dissection and recreation of a causative mutation revealed the importance of a non-sense mutation in the rho transcription terminator gene. Transcriptome analysis revealed how Rho impacts various B. thuringiensis genes involved in carbohydrate metabolism and virulence. Our work suggests that evolved multicellular aggregates have a fitness advantage over single cells when colonising plants, creating a trade-off between swimming and multicellularity in evolved lineages, in addition to unrelated alterations in pathogenicity.

scholarly journals Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

2020 ◽  
Vol 8 (4) ◽  
pp. 524
Author(s):  
José Luis Hernández Flores ◽  
Diana Salinas Landaverde ◽  
Yonuen Pacheco Huerta ◽  
Vania Lizeth Guerra Castillo ◽  
María de los Ángeles Barrios Sánchez ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Bacillus Cereus ◽  
Single Copy ◽  
Foodborne Illnesses ◽  
Regulatory Requirements ◽  
Bee Pollen ◽  
Enterotoxin Genes ◽  
Genes Encoding ◽  
Commercial Source ◽  
Bacillus Cereus Sensu Lato

Endospore-forming bacteria related to the Bacillus cereus group produce toxins that cause illnesses in organisms from invertebrates to mammals, including foodborne illnesses in humans. As commercial bee pollen can be contaminated with these bacteria, a comprehensive microbiological risk assessment of commercial bee pollen must be incorporated into the relevant regulatory requirements, including those that apply in Mexico. To facilitate detection of members of this group of bacteria, we have developed a PCR strategy that is based on the amplification of the single-copy tRNACys gene and specific genes associated with tRNACys to detect Bacillus cereus sensu lato (B. cereus s.l.). This tRNACys-PCR-based approach was used to examine commercial bee pollen for endospore-forming bacteria. Our analysis revealed that 3% of the endospore-forming colonies isolated from a commercial source of bee pollen were related to B. cereus s.l., and this result was corroborated by phylogenetic analysis, bacterial identification via MALDI-TOF MS, and detection of enterotoxin genes encoding the HBL and NHE complexes. The results show that the isolated colonies are closely related phylogenetically to B. cereus, B. thuringiensis, and B. bombysepticus. Our results indicate that the tRNACys-PCR, combined with other molecular tools, will be a useful approach for identifying B. cereus s.l. and will assist in controlling the spread of potential pathogens.

scholarly journals Adaptation and phenotypic diversification of Bacillus thuringiensis 407 biofilm are accompanied by a fuzzy spreader morphotype

2021 ◽  
Author(s):  
Yicen Lin ◽  
Gergely Maróti ◽  
Mikael Lenz Strube ◽  
Ákos T. Kovács
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Experimental Evolution ◽  
Insertion Sequence ◽  
Competitive Ability ◽  
Genetic Characterization ◽  
Phenotypic Diversification ◽  
Bacillus Cereus Sensu Lato ◽  
Adhesive Forces

AbstractBacillus cereus group (Bacillus cereus sensu lato) has a diverse ecology, including various species that produce biofilms on abiotic and biotic surfaces. While genetic and morphological diversification enable the adaptation of multicellular communities, this area remains largely unknown in the Bacillus cereus group. In this work, we dissected the experimental evolution of Bacillus thuringiensis 407 Cry-during continuous recolonization of plastic beads. We observed the evolution of a distinct colony morphotype that we named fuzzy spreader (FS) variant. Most multicellular traits of the FS variant displayed higher competitive ability versus the ancestral strain, suggesting an important role for diversification in the adaptation of B. thuringiensis to the biofilm lifestyle. Further genetic characterization of FS variant revealed the disruption of a guanylyltransferase gene by an insertion sequence (IS) element, which could be similarly observed in the genome of a natural isolate. The evolved FS and the deletion mutant in the guanylyltransferase gene (Bt407ΔrfbM) displayed similarly altered aggregation and hydrophobicity compared to the ancestor strain, suggesting that adaptation process highly depends on the physical adhesive forces.

scholarly journals Enterotoxin Gene Distribution and Genotypes of Bacillus cereus sensu lato Isolated from Cassava Starch

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 131
Author(s):  
Jennifer Sánchez-Chica ◽  
Margarita M. Correa ◽  
Angel E. Aceves-Diez ◽  
Laura M. Castañeda-Sandoval
Keyword(s):  
Bacillus Cereus ◽  
Raw Materials ◽  
Cassava Starch ◽  
Genomic Diversity ◽  
Enterotoxin Gene ◽  
Future Studies ◽  
Toxin Genes ◽  
Human Pathogenic Bacterium ◽  
Enterotoxin Genes ◽  
Bacillus Cereus Sensu Lato

Bacillus cereus is a human pathogenic bacterium found in foods with the potential to cause emesis and diarrhea. This study estimated the presence, toxigenic and genomic diversity of B. cereus s.l. obtained from cassava starch samples collected in bakeries and powdered food companies in Medellín (Colombia). Bacillus cereuss.l. was found in 43 of 75 (57%) cassava starch samples and 98 isolates were obtained. The nheABC, hblCDAB, cytK2, entFM and cesB toxin genes were detected by multiplex PCR and the most frequent operon was nheABC, whereas cesB gene was not found. Twelve toxigenic profiles were determined by the detection of toxin genes, and the most frequent profiles harbored all enterotoxin genes. A broad genomic diversity was detected according to GTG5-PCR fingerprinting results with 76 B. cereus s.l. grouped in sixteen clusters and the 22 isolates clustering separately. No relationship was observed between genomic background and toxigenic profiles. In general, the results showed a high genomic and enterotoxigenic diversity in B. cereus s.l. found in cassava starch. These results should incentive future studies to understand the distribution of B. cereus s.l. isolated on raw materials in comparison with finished products.

scholarly journals Bacillus cereus in Packaging Material: Molecular and Phenotypical Diversity Revealed

2021 ◽  
Vol 12 ◽  
Author(s):  
Paul Jakob Schmid ◽  
Stephanie Maitz ◽  
Clemens Kittinger
Keyword(s):  
Bacillus Cereus ◽  
Packaging Material ◽  
Pcr Analysis ◽  
Toxin Gene ◽  
Phylogenetic Groups ◽  
Group Vi ◽  
Gene Profiles ◽  
Water Plants ◽  
Crystal Toxin ◽  
Hemolysin Bl

The Bacillus cereus group has been isolated from soils, water, plants and numerous food products. These species can produce a variety of toxins including several enterotoxins [non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), cytotoxin K, and enterotoxin FM], the emetic toxin cereulide and insecticidal Bt toxins. This is the first study evaluating the presence of B. cereus in packaging material. Among 75 different isolates, four phylogenetic groups were detected (II, III, IV, and VI), of which the groups III and IV were the most abundant with 46.7 and 41.3%, respectively. One isolate was affiliated to psychrotolerant group VI. Growth experiments showed a mesophilic predominance. Based on PCR analysis, nhe genes were detectable in 100% of the isolates, while hbl genes were only found in 50.7%. The cereulide encoding gene was found in four out of 75 isolates, no isolate carried a crystal toxin gene. In total, thirteen different toxin gene profiles were identified. We showed that a variety of B. cereus group strains can be found in packaging material. Here, this variety lies in the presence of four phylogenetic groups, thirteen toxin gene profiles, and different growth temperatures. The results suggest that packaging material does not contain significant amounts of highly virulent strains, and the low number of cereulide producing strains is in accordance with other results.

Cloning of novel enterotoxin genes from Bacillus cereus and Bacillus thuringiensis.

1997 ◽  
Vol 63 (3) ◽  
pp. 1054-1057 ◽  
Author(s):  
S I Asano ◽  
Y Nukumizu ◽  
H Bando ◽  
T Iizuka ◽  
T Yamamoto
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Enterotoxin Genes

scholarly journals Activity of spore-crystal mixtures of new Bacillus thuringiensis strains against Dendrolimus pini (Lepidoptera: Lasiocampidae) and Spodoptera exigua (Lepidoptera: Noctuidae)

2018 ◽  
Vol 60 (2) ◽  
pp. 91-98
Author(s):  
Edyta Konecka ◽  
Adam Kaznowski ◽  
Małgorzata Stachowiak ◽  
Mirosław Maciąg
Keyword(s):  
Bacillus Thuringiensis ◽  
Spodoptera Exigua ◽  
Toxin Gene ◽  
Toxin Genes ◽  
Gene Profiles ◽  
Lepidoptera Noctuidae

AbstractWe estimated the usefulness of spore-crystals preparations of the twoB. thuringiensisisolates, MPU B9 and MPU B54, for reducing the number of pests. The potential insecticidal toxicities ofB. thuringiensisisolates were assessed by the analysis of the genes coding for crystalline proteins. The activities of spore-crystals preparations were determined againstDendrolimus piniL. (Lepidoptera: Lasiocampidae) and compared with the toxicity of spores and crystals ofB. thuringiensissubsp.kurstakiHD-1 from commercial biopesticide Foray. Although the analysis of crystalline toxin gene profiles indicated potentially higher activities of MPU B9 and MPU B54 crystals against the pests than that of HD-1, the toxicities of isolate and HD-1 preparations againstD. pinicaterpillars were similar. The LC50amounted to 3.42×104spores and crystals for HD-1, 3.36×104for MPU B9 and 3.5×104for MPU B54. Additionally, the toxicity of the MPU B54 preparation was evaluated againstSpodoptera exigua(Hubner) (Lepidoptera: Noctuidae). The LC50was 4.5×105spores and crystals of MPU B54, and 2.69×106spores and crystals of HD-1. The LC50of the MPU B54 preparation againstS. exiguawas approximately six-fold higher than that of HD-1. However, due to the very wide fiducidal limits for LC50values, which for both preparations overlap to a large extent, the toxicity of the preparations should be considered the same. The varied profiles of crystalline toxin genes and important toxicity of spore-crystal mixtures of isolates againstS. exiguaandD. piniindicate the effectiveness of the mixtures against pests and make the strains an alternative for HD-1 for reducing the number of insects.

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