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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 -
Ultrasonics Sonochemistry Oct 2021This study was aimed at providing new insights on the proteomic response of bacterial spores to ultrasound. Data-independent-acquisition method was used to quantify the...
This study was aimed at providing new insights on the proteomic response of bacterial spores to ultrasound. Data-independent-acquisition method was used to quantify the proteome change of Bacillus cereus spores after ultrasound treatment (200 W). This study revealed that 2485 proteins were extracted from Bacillus cereus spores, most of them were related to metabolism. After ultrasound treatment, the expression of 340 proteins were significantly changed (the fold change ≥ 2 and p < 0.05), of which 207 proteins were significantly down-regulated. KEGG pathway analysis showed that differentially expressed proteins mainly distributed in metabolism pathway, cell process pathway and genetic information processing pathway after ultrasound treatment. Furthermore, this study analyzed the differentially expressed proteins in significant enrichment pathways. In particular, the expression of key proteins in the phosphorylation reaction of spores was significantly decreased after ultrasound treatment. Thus, ATP synthesis rate decreased and the phosphorylation reaction inhibited. Also, the decrease of the expression of key proteins related to the tricarboxylic acid cycle led to the decrease of nutrients metabolism of spores. Ultrasound treatment induced the down-regulation of fatty acid synthetase expression and promoted fatty acid metabolism at the same time. The content of fatty acids decreased in spores consequently.
Topics: Bacillus cereus; Proteome; Proteomics; Spores, Bacterial; Ultrasonic Waves
PubMed: 34474268
DOI: 10.1016/j.ultsonch.2021.105732 -
MSphere Apr 2021The exosporium is the outermost spore layer of some and species and related organisms. It mediates the interactions of spores with their environment, modulates spore...
The exosporium is the outermost spore layer of some and species and related organisms. It mediates the interactions of spores with their environment, modulates spore adhesion and germination, and has been implicated in pathogenesis. In , the exosporium consists of a crystalline basal layer, formed mainly by the two cysteine-rich proteins CotY and ExsY, surrounded by a hairy nap composed of glycoproteins. The morphogenetic protein CotE is necessary for the integrity of the exosporium, but how CotE directs exosporium assembly remains unknown. Here, we used super-resolution fluorescence microscopy to follow the localization of SNAP-tagged CotE, CotY, and ExsY during sporulation and evidenced the interdependencies among these proteins. Complexes of CotE, CotY, and ExsY are present at all sporulation stages, and the three proteins follow similar localization patterns during endospore formation that are reminiscent of the localization pattern of CotE. We show that CotE guides the formation of one cap at both forespore poles by positioning CotY and then guides forespore encasement by ExsY, thereby promoting exosporium elongation. By these two actions, CotE ensures the formation of a complete exosporium. Importantly, we demonstrate that the assembly of the exosporium is not a unidirectional process, as previously proposed, but occurs through the formation of two caps, as observed during coat morphogenesis, suggesting that a general principle governs the assembly of the spore surface layers of Spores of are enveloped in an outermost glycoprotein layer. In the group, encompassing the and pathogens, this layer is easily recognizable by a characteristic balloon-like appearance and separation from the underlying coat by an interspace. In spite of its importance for the environmental interactions of spores, including those with host cells, the mechanism of assembly of the exosporium is poorly understood. We used super-resolution fluorescence microscopy to directly visualize the formation of the exosporium during the sporulation of , and we studied the localization and interdependencies of proteins essential for exosporium morphogenesis. We discovered that these proteins form a morphogenetic scaffold before a complete exosporium or coat is detectable. We describe how the different proteins localize to the scaffold and how they subsequently assemble around the spore, and we present a model for the assembly of the exosporium.
Topics: Bacillus cereus; Bacterial Proteins; Microscopy, Fluorescence; Spores, Bacterial
PubMed: 33883264
DOI: 10.1128/mSphere.00007-21 -
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 -
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 -
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 -
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 -
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 -
PloS One 2016We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory... (Comparative Study)
Comparative Study
We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed.
Topics: Bacillus cereus; Biosynthetic Pathways; Carbohydrates; Food Microbiology; Genome, Bacterial; Genotype; Phylogeny; Sequence Analysis, DNA
PubMed: 27272929
DOI: 10.1371/journal.pone.0156796