scholarly journals Characteristics of the Protein Complexes and Pores Formed by Bacillus cereus Hemolysin BL

Toxins ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 672 ◽  
Author(s):  
Nadja Jessberger ◽  
Richard Dietrich ◽  
Kristina Schauer ◽  
Stefanie Schwemmer ◽  
Erwin Märtlbauer ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Lipid Bilayers ◽  
Single Channel ◽  
Protein Complexes ◽  
Food Poisoning ◽  
Cell Binding ◽  
Channel Diameter ◽  
Toxic Activity ◽  
Target Cell Membrane ◽  
Hemolysin Bl

Bacillus cereus Hemolysin BL is a tripartite toxin responsible for a diarrheal type of food poisoning. Open questions remain regarding its mode of action, including the extent to which complex formation prior to cell binding contributes to pore-forming activity, how these complexes are composed, and the properties of the pores formed in the target cell membrane. Distinct complexes of up to 600 kDa were found on native gels, whose structure and size were primarily defined by Hbl B. Hbl L1 and L2 were also identified in these complexes using Western blotting and an LC-MS approach. LC-MS also revealed that many other proteins secreted by B. cereus exist in complexes. Further, a decrease of toxic activity at temperatures ≥60 °C was shown, which was unexpectedly restored at higher temperatures. This could be attributed to a release of Hbl B monomers from tight complexation, resulting in enhanced cell binding. In contrast, Hbl L1 was rather susceptible to heat, while heat treatment of Hbl L2 seemed not to be crucial. Furthermore, Hbl-induced pores had a rather small single-channel conductance of around 200 pS and a probable channel diameter of at least 1 nm on planar lipid bilayers. These were highly instable and had a limited lifetime, and were also slightly cation-selective. Altogether, this study provides astonishing new insights into the complex mechanism of Hbl pore formation, as well as the properties of the pores.

scholarly journals Exposure to Bacillus cereus in Water Buffalo Mozzarella Cheese

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1899
Author(s):  
Angela Michela Immacolata Montone ◽  
Federico Capuano ◽  
Andrea Mancusi ◽  
Orlandina Di Maro ◽  
Maria Francesca Peruzy ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Dairy Products ◽  
Water Buffalo ◽  
Diarrheal Disease ◽  
Food Poisoning ◽  
Mozzarella Cheese ◽  
Food Borne ◽  
Genes Encoding ◽  
Spoilage Bacterium ◽  
Hemolysin Bl

Bacillus cereus is a spoilage bacterium and is recognized as an agent of food poisoning. Two food-borne illnesses are caused by B. cereus: a diarrheal disease, associated with cytotoxin K, hemolysin BL, non-hemolytic enterotoxin and enterotoxin FM, and an emetic syndrome, associated with the cereulide toxin. Owing to the heat resistance of B. cereus and its ability to grow in milk, this organism should be considered potentially hazardous in dairy products. The present study assessed the risk of B. cereus poisoning due to the consumption of water buffalo mozzarella cheese. A total of 340 samples were analyzed to determine B. cereus counts (ISO 7932:2005); isolates underwent molecular characterization to detect the presence of genes encoding toxins. Eighty-nine (26.1%) samples harbored B. cereus strains, with values ranging from 2.2 × 102 to 2.6 × 106 CFU/g. Isolates showed eight different molecular profiles, and some displayed virulence characteristics. Bacterial counts and the toxin profiles of isolates were evaluated both separately and jointly to assess the risk of enteritis due to B. cereus following the consumption of buffalo mozzarella cheese. In conclusion, the results of the present study showed that the risk of poisoning by B. cereus following the consumption of this cheese was moderate.

Genetic Diversity, Antimicrobial Resistance, and Toxigenic Profiles of Bacillus cereus Strains Isolated from Sunsik

2012 ◽  
Vol 75 (2) ◽  
pp. 225-230 ◽  
Author(s):  
NARI LEE ◽  
JE MIN SUN ◽  
KYUNG YOON KWON ◽  
HYUN JUNG KIM ◽  
MINSEON KOO ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Fruits And Vegetables ◽  
Food Poisoning ◽  
Pcr Analysis ◽  
Contamination Level ◽  
Detection Rates ◽  
Its Gene ◽  
Hemolysin Bl ◽  
Encoding Genes ◽  
Element Sequence

Bacillus cereus can cause emetic and diarrheal types of food poisoning, but little study has been done on the toxins and toxin-encoding genes of B. cereus strains isolated from Sunsik, a Korean ready-to-eat food prepared from grains, fruits, and vegetables. In this study, 39 unique B. cereus strains were isolated and identified from Sunsik samples, with an average contamination level of 10 to 200 CFU/g. The detection rates of the hblACD, cytK, and bceT genes among all the strains were 48.7, 66.7, and 87.1%, respectively. All 39 B. cereus strains carried nheABC and entFM genes, and 36 strains also had the ces gene, which encodes an emetic toxin. Nonhemolytic enterotoxin and hemolysin BL enterotoxin were produced by 39 and 26 strains, respectively. The strains were separated into 13 profiles based on the presence or absence of toxins and their genes, as determined by antibody tests and PCR analysis. Profile 1 was the largest group, comprising 30.7% (12 of 39) of the B. cereus strains tested; these strains harbored all toxins and their genes. The B. cereus strains were susceptible to most of the antibiotics tested but were highly resistant to β-lactam antibiotics. The repetitive element sequence polymorphism PCR fingerprints of the B. cereus strains were not influenced by the presence of toxin genes or antibiotic resistance profiles. Our results suggest that B. cereus strains from Sunsik could cause either the diarrheal or emetic types of food poisoning because all strains isolated contained at least one toxin and its gene, although the level of B. cereus contamination in Sunsik was low.

scholarly journals DETECTION OF HBLD TOXIN GENE BY BACILLUS CEREUS ISOLATED FROM MEAT CURRY FOOD SAMPLES IN MALAYSIAN RESTAURANTS

2020 ◽  
Vol 4 (2) ◽  
pp. 68-72
Author(s):  
Marwan Msarah ◽  
Ahmed Alsier ◽  
Sahilah, A.M.
Keyword(s):  
Bacillus Cereus ◽  
Foodborne Pathogen ◽  
Food Poisoning ◽  
Egg Yolk ◽  
Food Samples ◽  
Blood Agar ◽  
Toxin Gene ◽  
Biochemical Tests ◽  
Isolation Medium ◽  
Hemolysin Bl

Bacillus cereus is a ubiquitous foodborne pathogen, can cause food poisoning, leading to infections, have two major types of food poisoning emetic and diarrheal. Foods rich in protein such as meat are associated with foodborne outbreaks of diarrhea caused by B. cereus. The aim of this study is to isolate and identify B. cereus from ready to eat (RTE) meat curry from restaurants in Malaysia and to detect hblD pathogenic gene of B. cereus isolates. Mannitol egg yolk polymyxin agar was used as a selective isolation medium. Commercially available kits and boiling methods were used for DNA extraction, samples acquired from restaurants were examined for the presence of Hemolysin BL gene by polymerase chain reaction (PCR). Among all isolates, twenty-four of B. cereus isolates detected for HBL enterotoxin production by the discontinuous pattern on HBL sheep blood agar then confirmed by biochemical tests. More than 58.33 % of the isolate showed discontinuous hemolysis pattern on HBl blood agar and 29.16% of the samples were shown positive for hblD gene that can cause diarrhea with the size of 807bp on gel. This study demonstrated that RTE meat curry was a potential source for entero-toxigenic B. cereus and the presence of the hblD toxin genes for the HBL complex in the isolates tested were highly associated. Therefore, these meat curry isolates should be regarded as potential toxin producers.

scholarly journals The Food Poisoning Toxins of Bacillus cereus

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 98 ◽  
Author(s):  
Richard Dietrich ◽  
Nadja Jessberger ◽  
Monika Ehling-Schulz ◽  
Erwin Märtlbauer ◽  
Per Einar Granum
Keyword(s):  
Bacillus Cereus ◽  
Diarrheal Disease ◽  
Current Knowledge ◽  
Food Poisoning ◽  
Toxin Production ◽  
Gastrointestinal Diseases ◽  
High Variability ◽  
Target Cells ◽  
Toxin Secretion ◽  
Hemolysin Bl

Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.

scholarly journals Binding to The Target Cell Surface Is The Crucial Step in Pore Formation of Hemolysin BL from Bacillus cereus

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 281 ◽  
Author(s):  
Nadja Jessberger ◽  
Richard Dietrich ◽  
Stefanie Schwemmer ◽  
Franziska Tausch ◽  
Valerie Schwenk ◽  
...  
Keyword(s):  
Cell Surface ◽  
Bacillus Cereus ◽  
Target Cell ◽  
Mode Of Action ◽  
Pore Formation ◽  
Food Poisoning ◽  
Crucial Step ◽  
Sequential Binding ◽  
L1 And L2 ◽  
Hemolysin Bl

A major virulence factor involved in Bacillus cereus food poisoning is the three-component enterotoxin hemolysin BL. It consists of the binding component B and the two lytic components L1 and L2. Studying its mode of action has been challenging, as natural culture supernatants additionally contain Nhe, the second three-component enterotoxin, and purification of recombinant (r) Hbl components has been difficult. In this study, we report on pore-forming, cytotoxic, cell binding and hemolytic activity of recently generated rHbl components expressed in E. coli. It is known that all three Hbl components are necessary for cytotoxicity and pore formation. Here we show that an excess of rHbl B enhances, while an excess of rHbl L1 hinders, the velocity of pore formation. Most rapid pore formation was observed with ratios L2:L1:B = 1:1:10 and 10:1:10. It was further verified that Hbl activity is due to sequential binding of the components B - L1 - L2. Accordingly, all bioassays proved that binding of Hbl B to the cell surface is the crucial step for pore formation and cytotoxic activity. Binding of Hbl B took place within minutes, while apposition of the following L1 and L2 occurred immediately. Further on, applying toxin components simultaneously, it seemed that Hbl L1 enhanced binding of B to the target cell surface. Overall, these data contribute significantly to the elucidation of the mode of action of Hbl, and suggest that its mechanism of pore formation differs substantially from that of Nhe, although both enterotoxin complexes are sequentially highly related.

scholarly journals Production of Diarrheal Enterotoxins and Other Potential Virulence Factors by Veterinary Isolates of Bacillus Species Associated with Nongastrointestinal Infections

2003 ◽  
Vol 69 (4) ◽  
pp. 2372-2376 ◽  
Author(s):  
Neil J. Rowan ◽  
George Caldow ◽  
Curtis G. Gemmell ◽  
Iain S. Hunter
Keyword(s):  
Bacillus Cereus ◽  
Virulence Factors ◽  
Dna Sequences ◽  
Food Poisoning ◽  
Brain Heart Infusion ◽  
Bacillus Species ◽  
Genes Encoding ◽  
Test Cell Line ◽  
Etiological Agents ◽  
Hemolysin Bl

ABSTRACT With the exceptions of Bacillus cereus and Bacillus anthracis, Bacillus species are generally perceived to be inconsequential. However, the relevance of other Bacillus species as food poisoning organisms and etiological agents in nongastrointestinal infections is being increasingly recognized. Eleven Bacillus species isolated from veterinary samples associated with severe nongastrointestinal infections were assessed for the presence and expression of diarrheagenic enterotoxins and other potential virulence factors. PCR studies revealed the presence of DNA sequences encoding hemolysin BL (HBL) enterotoxin complex and B. cereus enterotoxin T (BceT) in five B. cereus strains and in Bacillus coagulans NB11. Enterotoxin HBL was also harbored by Bacillus polymyxa NB6. After 18 h of growth in brain heart infusion broth, all seven Bacillus isolates carrying genes encoding enterotoxin HBL produced this toxin. Cell-free supernatant fluids from all 11 Bacillus isolates demonstrated cytotoxicity toward human HEp-2 cells; only one Bacillus licheniformis strain adhered to this test cell line, and none of the Bacillus isolates were invasive. This study constitutes the first demonstration that Bacillus spp. associated with serious nongastrointestinal infections in animals may harbor and express diarrheagenic enterotoxins traditionally linked to toxigenic B. cereus.

Enterotoxigenic and Genetic Profiles of Bacillus cereus Strains of Food Origin in Brazil

2008 ◽  
Vol 71 (10) ◽  
pp. 2115-2118 ◽  
Author(s):  
LINA CASALE ARAGON-ALEGRO ◽  
GABRIELA PALCICH ◽  
GRACIELA VOLZ LOPES ◽  
VINÍCIUS BUCCELLI RIBEIRO ◽  
MARIZA LANDGRAF ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Genetic Characterization ◽  
Protein Complexes ◽  
Toxin Production ◽  
Foodborne Illnesses ◽  
Good Practices ◽  
Production Capacities ◽  
Genetic Profiles ◽  
Hemolysin Bl

In Brazil, the incidence of Bacillus cereus outbreaks is unknown, and there is little information about B. cereus occurrence in food. In addition, data on toxin production and genetic characterization of the B. cereus isolates cannot be found. This pathogen causes two distinct types of toxin-mediated foodborne illnesses known as diarrheal and emetic syndromes. Diarrheal syndrome has been linked to three different enterotoxins: two protein complexes, hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE); and an enterotoxic protein, cytotoxin K (cytK). Emetic syndrome is related to cereulide, a toxin encoded by the ces gene. In this study, NHE and HBL production capacities of 155 strains of B. cereus isolated from Brazilian food products were evaluated with an immunoassay. Strains were also tested for the presence of the genes of the HBL and NHE complexes, cytK, cytK-1, cytK-2, and ces, using PCR. HBL was detected in 105 (67.7%) strains and NHE in 154 (99.4%) strains. All the strains harbored at least one gene of the NHE complex, while 96.1% of them were positive for at least one of those of the HBL complex. Genes cytK1 and ces were not detected. All strains showed toxigenic capacity and could represent a risk for consumers if good practices are not followed. This is the first report on toxigenic and genetic profiles of B. cereus strains isolated in Brazil.

KEJADIAN LUAR BIASA KERACUNAN “CUMI-CUMIAN” DI SEKOLAH DASAR NEGERI 1 TRASAN BANDONGAN KABUPATEN MAGELANG

2018 ◽  
Vol 7 (2) ◽  
pp. 131-136
Author(s):  
Nasir Ahmad
Keyword(s):  
Abdominal Pain ◽  
Bacillus Cereus ◽  
Rhodamine B ◽  
Attack Rate ◽  
Food Poisoning ◽  
Health Department ◽  
Analysis Data ◽  
Food Samples ◽  
Bivariate Analysis ◽  
School Committee

Background: On May 4th, 2016, at 12:30 district surveillance officer of Magelang Health Department received reports from Public Health Center of Bandongan about 21 students of SDN 1 Trasan who suffered from the same food-poisoning symptoms. Objective: Investigation was carried out to identify the source, how it spread and how to control it. Methods: This study used descriptive analytic and mapping the cases distribution location. The case was people experiencing symptoms of dizziness or abdominal pain or nausea or vomiting. Data analysis was done by using bivariate analysis. Data collection were done through interviews, observations and laboratory tests on the food samples. Results: The case was 50 students (from 1-6 grade students). The perceived symptoms were dizziness (77%), nausea (42%), abdominal pain (40%) and vomiting (8%). Attack rate found ranged from 14.3% to 60% with the highest Attack rate found on class three (60%). The incubation period of 15-240 minutes (mean 72.3 minutes). Calamari like positive Bacillus cereus and Rhodamine-B 10 mg/kg. Conclusion: The outbreak of food poisoning because calamari like contaminated Bacillus cereus. We suggested the school committee to provide the socialization of harmful food for the students. The teachers should restrict the permission for the food vendor to sell at school.   Keywords: Bacillus cereus, , Food Poisoning, Outbreak, Rhodamine B, School Food

scholarly journals Incidence and characterisation of Bacillus cereus bacteriophages from Thua Nao, a Thai fermented soybean product

2021 ◽  
Vol 12 (1) ◽  
pp. 85-93
Author(s):  
Wallapat Phongtang ◽  
Ekachai Chukeatirote
Keyword(s):  
Bacillus Cereus ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Morphological Analysis ◽  
Food Poisoning ◽  
Fermented Soybean ◽  
Foodborne Pathogenic Bacteria ◽  
Ph Range ◽  
Potential Use

Abstract Bacillus cereus is considered to be an important food poisoning agent causing diarrhea and vomiting. In this study, the occurrence of B. cereus bacteriophages in Thai fermented soybean products (Thua Nao) was studied using five B. cereus sensu lato indicator strains (four B. cereus strains and one B. thuringiensis strain). In a total of 26 Thua Nao samples, there were only two bacteriophages namely BaceFT01 and BaceCM02 exhibiting lytic activity against B. cereus. Morphological analysis revealed that these two bacteriophages belonged to the Myoviridae. Both phages were specific to B. cereus and not able to lyse other tested bacteria including B. licheniformis and B. subtilis. The two phages were able to survive in a pH range between 5 and 12. However, both phages were inactive either by treatment of 50°C for 2 h or exposure of UV for 2 h. It should be noted that both phages were chloroform-insensitive, however. This is the first report describing the presence of bacteriophages in Thua Nao products. The characterization of these two phages is expected to be useful in the food industry for an alternative strategy including the potential use of the phages as a biocontrol candidate against foodborne pathogenic bacteria.

scholarly journals Production of the Vacuolation Factor of Bacillus cereus Isolated from Vomiting-Type Food Poisoning.

1992 ◽  
Vol 54 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Kunihiro SHINAGAWA ◽  
Shoji OTAKE ◽  
Naonori MATSUSAKA ◽  
Shunji SUGII
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning
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