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FEMS Microbiology Reviews Jul 2008Bacillus cereus is widespread in nature and frequently isolated from soil and growing plants, but it is also well adapted for growth in the intestinal tract of insects... (Review)
Review
Bacillus cereus is widespread in nature and frequently isolated from soil and growing plants, but it is also well adapted for growth in the intestinal tract of insects and mammals. From these habitats it is easily spread to foods, where it may cause an emetic or a diarrhoeal type of food-associated illness that is becoming increasingly important in the industrialized world. The emetic disease is a food intoxication caused by cereulide, a small ring-formed dodecadepsipeptide. Similar to the virulence determinants that distinguish Bacillus thuringiensis and Bacillus anthracis from B. cereus, the genetic determinants of cereulide are plasmid-borne. The diarrhoeal syndrome of B. cereus is an infection caused by vegetative cells, ingested as viable cells or spores, thought to produce protein enterotoxins in the small intestine. Three pore-forming cytotoxins have been associated with diarrhoeal disease: haemolysin BL (Hbl), nonhaemolytic enterotoxin (Nhe) and cytotoxin K. Hbl and Nhe are homologous three-component toxins, which appear to be related to the monooligomeric toxin cytolysin A found in Escherichia coli. This review will focus on the toxins associated with foodborne diseases frequently caused by B. cereus. The disease characteristics are described, and recent findings regarding the associated toxins are discussed, as well as the present knowledge on virulence regulation.
Topics: Animals; Bacillus cereus; Diarrhea; Enterotoxins; Food Microbiology; Foodborne Diseases; Gastrointestinal Tract; Gene Expression Regulation, Bacterial; Humans; Pore Forming Cytotoxic Proteins; Soil Microbiology; Vomiting
PubMed: 18422617
DOI: 10.1111/j.1574-6976.2008.00112.x -
Microbiology (Reading, England) May 2021is recognized as a causative agent of gastrointestinal syndromes, but can also cause a devastating form of intraocular infection known as endophthalmitis. We have...
is recognized as a causative agent of gastrointestinal syndromes, but can also cause a devastating form of intraocular infection known as endophthalmitis. We have previously reported that the PlcR/PapR master virulence factor regulator system regulates intraocular virulence, and that the S-layer protein (SlpA) contributes to the severity of endophthalmitis. To better understand the role of other virulence genes in endophthalmitis, expression of a subset of factors was measured at the midpoint of disease progression in a murine model of endophthalmitis by RNA-Seq. Several cytolytic toxins were expressed at significantly higher levels than in BHI. The virulence regulators , , and were also expressed . However, at this timepoint, / was not detectable, although we previously reported that a mutant deficient in PlcR was attenuated in the eye. The motility-related genes , , and , and the chemotaxis-related gene were detected during infection. We have shown previously that motility and chemotaxis phenotypes are important in endophthalmitis. The variant of manganese superoxide dismutase was the most highly expressed gene . Expression of the surface layer protein gene, , an activator of Toll-like receptors (TLR)-2 and -4, was also detected during infection, albeit at low levels. Genes expressed in a mouse model of endophthalmitis might play crucial roles in the unique virulence of endophthalmitis, and serve as candidates for novel therapies designed to attenuate the severity of this often blinding infection.
Topics: Animals; Bacillus cereus; Bacterial Proteins; Endophthalmitis; Female; Gene Expression Regulation, Bacterial; Humans; Male; Mice; Mice, Inbred C57BL; Virulence
PubMed: 34032564
DOI: 10.1099/mic.0.001057 -
Toxins Feb 2021The emetic toxin cereulide is a 1.2 kDa dodecadepsipeptide produced by the food pathogen . As cereulide poses a serious health risk to humans, sensitive and specific...
The emetic toxin cereulide is a 1.2 kDa dodecadepsipeptide produced by the food pathogen . As cereulide poses a serious health risk to humans, sensitive and specific detection, as well as toxin purification and quantification, methods are of utmost importance. Recently, a stable isotope dilution assay tandem mass spectrometry (SIDA-MS/MS)-based method has been described, and an method for the quantitation of cereulide in foods was established by the International Organization for Standardization (ISO). However, although this SIDA-MS/MS method is highly accurate, the sophisticated high-end MS equipment required for such measurements limits the method's suitability for microbiological and molecular research. Thus, we aimed to develop a method for cereulide toxin detection and isolation using equipment commonly available in microbiological and biochemical research laboratories. Reproducible detection and relative quantification of cereulide was achieved, employing reversed phase chromatography (RPC). Chromatographic signals were cross validated by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS). The specificity of the RPC method was tested using a test panel of strains that included non-emetic representatives of the group, emetic strains, and cereulide-deficient isogenic mutants. In summary, the new method represents a robust, economical, and easily accessible research tool that complements existing diagnostics for the detection and quantification of cereulide.
Topics: Bacillus cereus; Chromatography, Reverse-Phase; Depsipeptides; Foodborne Diseases; Gram-Positive Bacterial Infections; Humans; Reproducibility of Results; Vomiting
PubMed: 33557428
DOI: 10.3390/toxins13020115 -
Clinical Microbiology Reviews Oct 1993Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the... (Review)
Review
Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the consumption of rice-based dishes. The organism produces an emetic or diarrheal syndrome induced by an emetic toxin and enterotoxin, respectively. Other toxins are produced during growth, including phospholipases, proteases, and hemolysins, one of which, cereolysin, is a thiol-activated hemolysin. These toxins may contribute to the pathogenicity of B. cereus in nongastrointestinal disease. B. cereus isolated from clinical material other than feces or vomitus was commonly dismissed as a contaminant, but increasingly it is being recognized as a species with pathogenic potential. It is now recognized as an infrequent cause of serious nongastrointestinal infection, particularly in drug addicts, the immunosuppressed, neonates, and postsurgical patients, especially when prosthetic implants such as ventricular shunts are inserted. Ocular infections are the commonest types of severe infection, including endophthalmitis, panophthalmitis, and keratitis, usually with the characteristic formation of corneal ring abscesses. Even with prompt surgical and antimicrobial agent treatment, enucleation of the eye and blindness are common sequelae. Septicemia, meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections are other manifestations of severe disease. B. cereus produces beta-lactamases, unlike Bacillus anthracis, and so is resistant to beta-lactam antibiotics; it is usually susceptible to treatment with clindamycin, vancomycin, gentamicin, chloramphenicol, and erythromycin. Simultaneous therapy via multiple routes may be required.
Topics: Bacillaceae Infections; Bacillus; Bacillus cereus; Bacteremia; Enterotoxins; Eye Infections, Bacterial; Foodborne Diseases; Hemolysin Proteins; Humans; Phospholipases; Wound Infection
PubMed: 8269390
DOI: 10.1128/CMR.6.4.324 -
Gene cloning and molecular characterization of a thermostable chitosanase from Bacillus cereus TY24.BMC Biotechnology Oct 2022An important conceptual advance in health and the environment has been recognized that enzymes play a key role in the green processing industries. Of particular...
BACKGROUND
An important conceptual advance in health and the environment has been recognized that enzymes play a key role in the green processing industries. Of particular interest, chitosanase is beneficial for recycling the chitosan resource and producing chitosan oligosaccharides. Also, chitosan gene expression and molecular characterization will promote understanding of the biological function of bacterial chitosanase as well as explore chitosanase for utilizing chitosan resources.
RESULTS
A chitosanase-producing bacterium TY24 was isolated and identified as Bacillus cereus. Moreover, the chitosanase gene was cloned and expressed in Escherichia coli. Sequence analysis reveals that the recombinant chitosanase (CHOE) belongs to the glycoside hydrolases 8 family. The purified CHOE has a molecular weight of about 48 kDa and the specific activity of 1150 U/mg. The optimal pH and temperature of CHOE were 5.5 and 65 °C, respectively. The enzyme was observed stable at the pH range of 4.5-7.5 and the temperature range of 30-65 °C. Especially, the half-life of CHOE at 65 °C was 161 min. Additionally, the activity of CHOE was remarkably enhanced in the presence of Mn, Cu, Mg and K, beside Ca at 5 mM. Especially, the activity of CHOE was enhanced to more than 120% in the presence of 1% of various surfactants. CHOE exhibited the highest substrate specificity toward colloid chitosan.
CONCLUSION
A bacterial chitosanase was cloned from B. cereus and successfully expressed in E. coli (BL21) DE3. The recombinant enzyme displayed good stability under acid pH and high-temperature conditions.
Topics: Bacillus cereus; Chitosan; Escherichia coli; Glycoside Hydrolases; Cloning, Molecular; Hydrogen-Ion Concentration
PubMed: 36303174
DOI: 10.1186/s12896-022-00762-6 -
PloS One 2021Bacillus cereus is a foodborne pathogen and can form biofilms on food contact surfaces, which causes food hygiene problems. While it is necessary to understand...
Bacillus cereus is a foodborne pathogen and can form biofilms on food contact surfaces, which causes food hygiene problems. While it is necessary to understand strain-dependent variation to effectively control these biofilms, strain-to-strain variation in the structure of B. cereus biofilms is poorly understood. In this study, B. cereus strains from tatsoi (BC4, BC10, and BC72) and the ATCC 10987 reference strain were incubated at 30°C to form biofilms in the presence of the extracellular matrix-degrading enzymes DNase I, proteinase K, dispase II, cellulase, amyloglucosidase, and α-amylase to assess the susceptibility to these enzymes. The four strains exhibited four different patterns in terms of biofilm susceptibility to the enzymes as well as morphology of surface-attached biofilms or suspended cell aggregates. DNase I inhibited the biofilm formation of strains ATCC 10987 and BC4 but not of strains BC10 and BC72. This result suggests that some strains may not have extracellular DNA, or their extracellular DNA may be protected in their biofilms. In addition, the strains exhibited different patterns of susceptibility to protein- and carbohydrate-degrading enzymes. While other strains were resistant, strains ATCC 10987 and BC4 were susceptible to cellulase, suggesting that cellulose or its similar polysaccharides may exist and play an essential role in their biofilm formation. Our compositional and imaging analyses of strains ATCC 10987 and BC4 suggested that the physicochemical properties of their biofilms are distinct, as calculated by the carbohydrate to protein ratio. Taken together, our study suggests that the extracellular matrix of B. cereus biofilms may be highly diverse and provides insight into the diverse mechanisms of biofilm formation among B. cereus strains.
Topics: Bacillus cereus; Biofilms; Cellulase; Deoxyribonuclease I; Endopeptidase K; Endopeptidases; Enzymes; Extracellular Matrix; Glucan 1,4-alpha-Glucosidase; Spores, Bacterial; alpha-Amylases
PubMed: 34133441
DOI: 10.1371/journal.pone.0245708 -
BMC Microbiology Oct 2020Bacillus cereus is a foodborne pathogen commonly found in nature and food and can cause food spoilage and health issues. Although the prevalence of B. cereus in foods...
BACKGROUND
Bacillus cereus is a foodborne pathogen commonly found in nature and food and can cause food spoilage and health issues. Although the prevalence of B. cereus in foods has been reported worldwide, the extent of contamination in edible fungi, which has become increasingly popular as traditional or functional food, is largely unknown. Here we investigated the prevalence, toxin genes' distribution, antibiotic resistance, and genetic diversity of B. cereus isolated from edible fungi in China.
RESULTS
Six hundred and ninety-nine edible fungi samples were collected across China, with 198 (28.3%) samples found to be contaminated by B. cereus, with an average contamination level of 55.4 most probable number (MPN)/g. Two hundred and forty-seven B. cereus strains were isolated from the contaminated samples. Seven enterotoxin genes and one cereulide synthetase gene were detected. The detection frequencies of all enterotoxin genes were ≥ 80%, whereas the positive rate of the cesB gene in B. cereus was 3%. Most isolates were resistant to penicillins, β-lactam/β-lactamase inhibitor combinations, cephems, and ansamycins, but were susceptible to penems, aminoglycosides, macrolides, ketolide, glycopeptides, quinolones, phenylpropanol, tetracyclines, lincosamides, streptogramins, and nitrofurans. Meanwhile, 99.6% of all isolates displayed multiple antimicrobial resistance to three or more classes of antimicrobials. Using genetic diversity analysis, all isolates were defined in 171 sequence types (STs), of which 83 isolates were assigned to 78 new STs.
CONCLUSIONS
This study provides large-scale insight into the prevalence and potential risk of B. cereus in edible fungi in China. Approximately one-third of the samples were contaminated with B. cereus, and almost all isolates showed multiple antimicrobial resistance. Detection frequencies of all seven enterotoxin genes were equal to or more than 80%. These new findings may indicate a need for proper pre-/post-processing of edible fungi to eliminate B. cereus, thereby preventing the potential risk to public health.
Topics: Agaricales; Anti-Bacterial Agents; Bacillus cereus; China; Colony Count, Microbial; Drug Resistance, Microbial; Enterotoxins; Food Contamination; Food Microbiology
PubMed: 33054711
DOI: 10.1186/s12866-020-01996-0 -
Biological & Pharmaceutical Bulletin 2020Bacillus cereus is well known as a causative agent of food poisoning but it also causes bacteremia and endophthalmitis in nosocomial infections. However, as an... (Review)
Review
Bacillus cereus is well known as a causative agent of food poisoning but it also causes bacteremia and endophthalmitis in nosocomial infections. However, as an environmental bacterium that lives in soil, it is often treated as simple contamination by hospitals. In recent years, highly pathogenic B. cereus strains that are similar to Bacillus anthracis have been detected in hospitals. The B. cereus sphingomyelinase contributes to its pathogenicity, as do sphingomyelinases produced by Staphylococcus aureus, Pseudomonas aeruginosa, Helicobacter pylori, and B. anthracis. Highly pathogenic B. cereus produces a large amount of sphingomyelinase. In this review, we describe the regulation of sphingomyelinase expression through the PlcR-PapR system, the pathogenicity of bacterial sphingomyelinases, and their potential as therapeutic drug targets.
Topics: Bacillus cereus; Humans; Sphingomyelin Phosphodiesterase
PubMed: 32009113
DOI: 10.1248/bpb.b19-00762 -
Journal of Food Protection Mar 2005The genus Bacillus includes members that demonstrate a wide range of diversity from physiology and ecological niche to DNA sequence and gene regulation. The species of... (Review)
Review
The genus Bacillus includes members that demonstrate a wide range of diversity from physiology and ecological niche to DNA sequence and gene regulation. The species of most interest tend to be known for their pathogenicity and are closely linked genetically. Bacillus anthracis causes anthrax, and Bacillus thuringiensis is widely used for its insecticidal properties but has also been associated with foodborne disease. Bacillus cereus causes two types of food poisoning, the emetic and diarrheal syndromes, and a variety of local and systemic infections. Although in this review we provide information on the genus and a variety of species, the primary focus is on the B. cereus strains and toxins that are involved in foodborne illness. B. cereus produces a large number of potential virulence factors, but for the majority of these factors their roles in specific infections have not been established. To date, only cereulide and the tripartite hemolysin BL have been identified specifically as emetic and diarrheal toxins, respectively. Nonhemolytic enterotoxin, a homolog of hemolysin BL, also has been associated with the diarrheal syndrome. Recent findings regarding these and other putative enterotoxins are discussed.
Topics: Bacillus cereus; Bacterial Typing Techniques; Enterotoxins; Foodborne Diseases; Humans; Phylogeny; Species Specificity
PubMed: 15771198
DOI: 10.4315/0362-028x-68.3.636 -
PloS One 2021Microorganisms that cause foodborne illnesses challenge the food industry; however, environmental studies of these microorganisms on raw grain, prior to food processing,...
Microorganisms that cause foodborne illnesses challenge the food industry; however, environmental studies of these microorganisms on raw grain, prior to food processing, are uncommon. Bacillus cereus sensu lato is a diverse group of bacteria that is common in our everyday environment and occupy a wide array of niches. While some of these bacteria are beneficial to agriculture due to their entomopathogenic properties, others can cause foodborne illness; therefore, characterization of these bacteria is important from both agricultural and food safety standpoints. We performed a survey of wheat and flax grain samples in 2018 (n = 508) and 2017 (n = 636) and discovered that B. cereus was present in the majority of grain samples, as 56.3% and 85.2%, in two years respectively. Whole genome sequencing and comparative genomics of 109 presumptive B. cereus isolates indicates that most of the isolates were closely related and formed two genetically distinct groups. Comparisons to the available genomes of reference strains suggested that the members of these two groups are not closely related to strains previously reported to cause foodborne illness. From the same data set, another, genetically more diverse group of B. cereus was inferred, which had varying levels of similarity to previously reported strains that caused disease. Genomic analysis and PCR amplification of genes linked to toxin production indicated that most of the isolates carry the genes nheA and hbID, while other toxin genes and gene clusters, such as ces, were infrequent. This report of B. cereus on grain from Canada is the first of its kind and demonstrates the value of surveillance of bacteria naturally associated with raw agricultural commodities such as cereal grain and oilseeds.
Topics: Bacillus cereus; Bacterial Proteins; Bacterial Toxins; Canada; Edible Grain; Flax; Genome, Bacterial; Genomics; High-Throughput Nucleotide Sequencing; Phylogeny; Triticum; Whole Genome Sequencing
PubMed: 34735500
DOI: 10.1371/journal.pone.0259209