scholarly journals Further Insights into the Toxicity of Bacillus cytotoxicus Based on Toxin Gene Profiling and Vero Cell Cytotoxicity Assays

Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 234
Author(s):  
Johanna Burtscher ◽  
Danai Etter ◽  
Michael Biggel ◽  
Janine Schlaepfer ◽  
Sophia Johler

Bacillus cytotoxicus belongs to the Bacillus cereus group that also comprises the foodborne pathogen Bacillus cereus sensu stricto, Bacillus anthracis causing anthrax, as well as the biopesticide Bacillus thuringiensis. The first B. cytotoxicus was isolated in the context of a severe food poisoning outbreak leading to fatal cases of diarrheal disease. Subsequent characterization of the outbreak strain led to the conclusion that this Bacillus strain was highly cytotoxic and eventually resulted in the description of a novel species, whose name reflects the observed toxicity: B. cytotoxicus. However, only a few isolates of this species have been characterized with regard to their cytotoxic potential and the role of B. cytotoxicus as a causative agent of food poisoning remains largely unclear. Hence, the aim of this study was to gain further insights into the toxicity of B. cytotoxicus. To this end, 19 isolates were obtained from mashed potato powders and characterized by toxin gene profiling and Vero cell cytotoxicity assays. All isolates harbored the cytK1 (cytotoxin K1) gene and species-specific variants of the nhe (non-hemolytic enterotoxin) gene. The isolates exhibited low or no toxicity towards Vero cells. Thus, this study indicates that the cytotoxic potential of B. cytotoxicus may be potentially lower than initially assumed.

2020 ◽  
Vol 4 (2) ◽  
pp. 68-72
Author(s):  
Marwan Msarah ◽  
Ahmed Alsier ◽  
Sahilah, A.M.

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.


Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2667 ◽  
Author(s):  
Nalini Ramarao ◽  
Seav-Ly Tran ◽  
Marco Marin ◽  
Jasmina Vidic

Bacillus cereus is an opportunistic foodborne pathogen causing food intoxication and infectious diseases. Different toxins and pathogenic factors are responsible for diarrheal syndrome, like nonhemolytic enterotoxin Nhe, hemolytic enterotoxin Hbl, enterotoxin FM and cytotoxin K, while emetic syndrome is caused by the depsipeptide cereulide toxin. The traditional method of B. cereus detection is based on the bacterial culturing onto selective agars and cells enumeration. In addition, molecular and chemical methods are proposed for toxin gene profiling, toxin quantification and strain screening for defined virulence factors. Finally, some advanced biosensors such as phage-based, cell-based, immunosensors and DNA biosensors have been elaborated to enable affordable, sensitive, user-friendly and rapid detection of specific B. cereus strains. This review intends to both illustrate the state of the B. cereus diagnostic field and to highlight additional research that is still at the development level.


2022 ◽  
Vol 52 (4) ◽  
Author(s):  
Hayriye Yeşim Can ◽  
Mehmet Elmalı ◽  
Alper Karagöz ◽  
Hüseyin Burak Dişli

ABSTRACT: Bacillus cereus is an aerobic and facultatively anaerobic, spore-forming bacterium, and it is found naturally in soil and poses a risk factor for the contamination of food and foodstuffs including cereals, vegetables, spices, ready-to-eat (RTE) foods, meats, milk, and dairy products. This study determined the prevalence of B. cereus in raw poultry meat, raw cow’s milk, cheese, spices, and RTE foods in Hatay province. The study also analysed the psychrotrophic properties, toxigenic characteristics, and pulsed-field gel electrophoresis (PFGE) profiles of the isolates. The levels of contamination with B. cereus determined for cheese, raw milk, RTE foods, spices, and raw poultry meat were 16.6%, 34.2%, 42.8%, 49%, and 55.5%, respectively. B. cereus was isolated from 84 (42%) of the 200 samples analysed and the 84 isolates were verified by PCR analysis targeting the haemolysin gene specific for B. cereus. Of the total isolates, 64 (76.1%) were psychrotrophic. The toxin gene profiling of B. cereus isolates was determined by amplifying the four genes nhe, hbl, cytK, and ces. The nhe and cytK genes were most frequently detected in the isolates, while the hbl and ces genes were not found. In addition, a high genetic relationship between the isolates was detected at a 92% similarity level by PFGE analysis. In conclusion, the occurrence of both psychrotrophic and toxigenic B. cereus strains in this study indicated a potential risk for food spoilage and food poisoning.


Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1899
Author(s):  
Angela Michela Immacolata Montone ◽  
Federico Capuano ◽  
Andrea Mancusi ◽  
Orlandina Di Maro ◽  
Maria Francesca Peruzy ◽  
...  

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.


Toxins ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 454 ◽  
Author(s):  
Xiao-Ye Liu ◽  
Qiao Hu ◽  
Fei Xu ◽  
Shuang-Yang Ding ◽  
Kui Zhu

Bacillus cereus is a common and ubiquitous foodborne pathogen with an increasing prevalence rate in dairy products in China. High and unmet demands for such products, particularly milk, raise the risk of B. cereus associated contamination. The presence of B. cereus and its virulence factors in dairy products may cause food poisoning and other illnesses. Thus, this review first summarizes the epidemiological characteristics and analytical assays of B. cereus from dairy products in China, providing insights into the implementation of intervention strategies. In addition, the recent achievements on the cytotoxicity and mechanisms of B. cereus are also presented to shed light on the therapeutic options for B. cereus associated infections.


2005 ◽  
Vol 68 (10) ◽  
pp. 2123-2130 ◽  
Author(s):  
I-CHEN YANG ◽  
DANIEL YANG-CHIH SHIH ◽  
TSUI-PING HUANG ◽  
YUN-PU HUANG ◽  
JAN-YI WANG ◽  
...  

Five different enterotoxins and one emetic toxin of Bacillus cereus have been characterized. To amplify all of the enterotoxin and emetic-specific sequences of the species in the B. cereus group, a multiplex PCR with 12 primer pairs was established. In developing the assay method, a common terminal sequence at the 3′ ends of all primers was chosen and a hot start Taq polymerase was used to overcome primer dimer formation. The assay was successfully applied to analyze the toxigenic potential of 162 food-poisoning and food-related strains. Results showed that there were 10 toxigenic patterns for all the test strains. All of the B. cereus strains carried at least one toxin gene. More than 70% of Bacillus mycoides strains carried no known toxin genes. The toxin profiles and toxin genes of B. mycoides strains were significantly different from B. cereus strains (P < 0.05), although the two species were closely related. The results suggest that many B. mycoides strains might be less prone to cause food poisoning. They also indicate the importance of detecting the toxin genes together with the detection of the species in the B. cereus group.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 98 ◽  
Author(s):  
Richard Dietrich ◽  
Nadja Jessberger ◽  
Monika Ehling-Schulz ◽  
Erwin Märtlbauer ◽  
Per Einar Granum

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.


LWT ◽  
2021 ◽  
Vol 140 ◽  
pp. 110824
Author(s):  
Hui Guo ◽  
Pengfei Yu ◽  
Shubo Yu ◽  
Juan Wang ◽  
Junhui Zhang ◽  
...  

2020 ◽  
Vol 8 (3) ◽  
pp. 76-79
Author(s):  
Mahtab Hamidpour ◽  
Saman Mahdavi

Background: Bacillus cereus is a gram-positive and spore-forming bacterium which is widespread in nature. It also has been known as a major foodborne pathogen that often plays a role in the contamination of ready-to-eat and dairy products. It causes two different types of food poisoning in human: the diarrheal type and the emetic type. Objective: The current study was planned to determine the prevalence of ces and cytk genes of Bacillus cereus isolated from raw milk in Tabriz, Iran. Materials and Methods: In this study, 40 B. cereus strains isolated from cow raw milk, that had already been identified phenotypically, were assessed for molecular confirmation by polymerase chain reaction (PCR) method. Then, they were evaluated for presence of ces and cytK genes by specific primers. Results: Of 40 B. cereus strains, 39 strains were confirmed molecularly. The frequency of cytK and ces genes was reported 38 (97.43%) and 0 (0%), respectively. Conclusion: The results of present study showed that B. cereus strains isolated from raw milk had high potential in causing diarrhea poisoning. Therefore, using procedures to reduce the bacterial contamination during the processing of dairy product is essential.


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