Diarrhoeal toxin production at low temperature by selected strains
 
of Bacillus cereus

Fermanian, Christophe; Lapeyre, C.; Frémy, J. M.; Claisse, Maurice

doi:10.1017/s0022029997002379

Cited by 22 publications

(15 citation statements)

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“…In a first systematic approach we compared enterotoxin gene expression of a representative B. cereus strain set. Previous studies compared enterotoxin expression in single B. cereus strains under varying growth temperature (Van Netten et al, 1990 ; Fermanian et al, 1997 ; Rejasse et al, 2012 ), oxygen availability (Duport et al, 2004 ; Van Der Voort and Abee, 2009 ), lowered oxidation-reduction potential (ORP) (Duport et al, 2006 ; Zigha et al, 2007 ; Esbelin et al, 2009 ) and differing availability of nutrients, for instance sugars (Ouhib et al, 2006 ; Ouhib-Jacobs et al, 2009 ). In our study, quantification of nheB and hblD mRNA levels at early exponential and late exponential growth phase/transition phase by qRT-PCR revealed highly strain-dependent variations in toxin gene transcript levels and transcription efficiency.…”

Section: Discussionmentioning

confidence: 99%

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

et al. 2015

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In recent years Bacillus cereus has gained increasing importance as a food poisoning pathogen. It is the eponymous member of the B. cereus sensu lato group that consists of eight closely related species showing impressive diversity of their pathogenicity. The high variability of cytotoxicity and the complex regulatory network of enterotoxin expression have complicated efforts to predict the toxic potential of new B. cereus isolates. In this study, comprehensive analyses of enterotoxin gene sequences, transcription, toxin secretion and cytotoxicity were performed. For the first time, these parameters were compared in a whole set of B. cereus strains representing isolates of different origin (food or food poisoning outbreaks) and of different toxic potential (enteropathogenic and apathogenic) to elucidate potential starting points of strain-specific differential toxicity. While toxin gene sequences were highly conserved and did not allow for differentiation between high and low toxicity strains, comparison of nheB and hblD enterotoxin gene transcription and Nhe and Hbl protein titers revealed not only strain-specific differences but also incongruence between toxin gene transcripts and toxin protein levels. With one exception all strains showed comparable capability of protein secretion and so far, no secretion patterns specific for high and low toxicity strains were identified. These results indicate that enterotoxin expression is more complex than expected, possibly involving the orchestrated interplay of different transcriptional regulator proteins, as well as posttranscriptional and posttranslational regulatory mechanisms plus additional influences of environmental conditions.

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Section: Discussionmentioning

confidence: 99%

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

et al. 2015

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“…In a study carried out by Kunisaki and Hyashi [27], they reported that resting cells of Escherichia coli formed N-nitrosamines at an optimum pH of 8.0, whereas an optimum pH of 3.4 was noticed during chemical nitrosation. Certain microbiological studies revealed that optimum growth of B cereus occurred at a pH range of 4.9 -10.0 [31,32]. However, Shukor et al [33] reported a pH range of 6.8 -7.0 for the optimum growth of this bacterium.…”

Section: Discussionmentioning

confidence: 99%

N-Nitrosation of Dimethylamine by Bacillus cereus Isolated from Fermented Palm Sap (Elaeis guineensis)

Adeleke¹,

Adedosu²,

Oyewo³

et al. 2018

CRJ

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This study investigated the nitrosating activities of intact cells and cell fractions of Bacillus cereus isolated from fermented palm wine (Elaeis guineensis) during incubation with dimethylamine and nitrite or nitrate. The pH values of the incubation mixtures were 7.2 ± 0.07 and 7.1 ± 0.07 in the presence of nitrite and nitrate, respectively. The N-Nitrosodimethylamine (NDMA) level in cell debris was significantly higher compared with cell extract, cell suspension and sterile controls. The time-course of NDMA formation in cell debris showed a significant (p < 0.05) early decline followed by an increase. The kinetic data obtained from Lineweaver-Burk plots of NDMA formation showed that Michaelis-Menten constant (K m) value was 37.5% lower, while initial velocity (V max) was 20.0% higher in cell debris relative to cell extract, when a fixed DMA concentration was used against varying nitrite concentrations. However, at a fixed nitrite concentration against varying DMA concentration, K m value was 44.4% lower, while V max was 166.7% higher in cell debris compared with cell extract. Investigation of nitrosation mechanism showed that V max values in the cell debris were 41.7, 50.0 and 55.6 µmol NDMA/mg protein, while the values were 34.5, 37.0 and 43.5 µmol NDMA/mg protein in cell extract for the respective three nitrite concentrations. This study has shown that intact Bacillus cereus cells catalyzed nitrosation of dimethylamine at near neutral pH, and the nitrosation, which was higher in cell debris than cell extract of the bacterium, followed a sequential mechanism of enzyme catalysis.

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“…The diarrhoeal enterotoxins can be produced in the temperature range of 10-43°C, with an optimum of 32°C (Kramer and Gilbert 1989;Fermanian et al 1997). Production occurs between pH 5.5-10, with an optimum of pH 8 (Sutherland and Limond 1993).…”

Section: Virulence and Infectivitymentioning

confidence: 99%

“…Antimicrobials which inhibit the growth of B. cereus include benzoate, sorbates and ethylenediaminetetraacetic acid (Jenson and Moir 2003). Table 1: Limits for growth of B. cereus and toxin production when other conditions are near optimum (Kramer and Gilbert 1989;Sutherland and Limond 1993;ICMSF 1996;Fermanian et al 1997;Finlay et al 2000…”

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confidence: 99%

Bacillus Cereus

Sankararaman

Velayuthan

2013

Pediatrics in Review

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Bacillus cereus is a spore forming bacterium that produces toxins that cause vomiting or diarrhoea. Symptoms are generally mild and short-lived (up to 24 hours). B. cereus is commonly found in the environment (e.g. soil) as well as a variety of foods. Spores are able to survive harsh environments including normal cooking temperatures. Description of the organism B. cereus is a Gram-positive, motile (flagellated), spore-forming, rod shaped bacterium that belongs to the Bacillus genus. Species within this genus include B. anthracis, B. cereus, B. mycoides, B. thuringiensis, B. pseudomycoides and B. weihenstephanensis (Rajkowski and Bennett 2003; Montville and Matthews 2005). Genomic sequencing data has shown B. anthracis, B. cereus and B. thuringiensis to be very closely related (Rasko et al. 2004) with their 16S rRNA gene sequence sharing more than 99% similarity (Ash et al. 1991). B. cereus is widespread in nature and readily found in soil, where it adopts a saprophytic life cycle; germinating, growing and sporulating in this environment (Vilain et al. 2006). Spores are more resistant to environmental stress than vegetative cells due to their metabolic dormancy and tough physical nature (Jenson and Moir 2003). B. cereus produces two types of toxins-emetic (vomiting) and diarrhoeal-causing two types of illness. The emetic syndrome is caused by emetic toxin produced by the bacteria during the growth phase in the food. The diarrhoeal syndrome is caused by diarrhoeal toxins produced during growth of the bacteria in the small intestine (Ehling-Schulz et al. 2006). Growth and survival characteristics Strains of B. cereus vary widely in their growth and survival characteristics (refer to Table 1). Isolates from food and humans can be subdivided as either mesophilic or psychrotrophic strains. Mesophilic strains grow well at 37°C but do not grow below 10°C; psychrotrophic strains grow well at refrigeration temperatures but grow poorly at 37°C (Wijnands et al. 2006a). All isolates of B. cereus associated with emetic toxin production have been found to be mesophilic in nature (Pielaat et al. 2005; Wijnands et al. 2006b).

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Diarrhoeal toxin production at low temperature by selected strains of Bacillus cereus

Cited by 22 publications

References 0 publications

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

<i>N</i>-Nitrosation of Dimethylamine by <i>Bacillus cereus</i> Isolated from Fermented Palm Sap (<i>Elaeis guineensis</i>)

Bacillus Cereus

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Diarrhoeal toxin production at low temperature by selected strains of Bacillus cereus

Cited by 22 publications

References 0 publications

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

From genome to toxicity: a combinatory approach highlights the complexity of enterotoxin production in Bacillus cereus

&lt;i&gt;N&lt;/i&gt;-Nitrosation of Dimethylamine by &lt;i&gt;Bacillus cereus&lt;/i&gt; Isolated from Fermented Palm Sap (&lt;i&gt;Elaeis guineensis&lt;/i&gt;)

Bacillus Cereus

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<i>N</i>-Nitrosation of Dimethylamine by <i>Bacillus cereus</i> Isolated from Fermented Palm Sap (<i>Elaeis guineensis</i>)