Identification of emetic toxin producing<i>Bacillus cereus</i>strains by a novel molecular assay

Ehling‐Schulz, Monika; Fricker, Martina; Scherer, Siegfried

doi:10.1016/s0378-1097(04)00066-7

Cited by 166 publications

(96 citation statements)

References 29 publications

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“…Cereulide is a small heat stable cyclic dodecadepsipeptide produced by some strains of B. cereus which has high toxicity to humans (1,36). Cereulide is synthesized by a non-ribosomal peptide synthetase, encoded by the ces genes located on a 270-kb pXOI-like virulence plasmid named pCER270 (10,26), more often found associated with clinical isolates of B. cereus. A recent study has reported the presence of cesA, but not cesB, in B. pumilus and B. licheniformis isolated from bovine mastitis (20).…”

Section: Discussionmentioning

confidence: 99%

Biochemical and molecular characterization of Bacillus pumilus isolated from coastal environment in Cochin, India

Parvathi¹,

Krishna²,

Jose³

et al. 2009

Braz. J. Microbiol.

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Bacillus species constitute a diverse group of bacteria widely distributed in soil and the aquatic environment. In this study, Bacillus strains isolated from the coastal environment of Cochin, India were identified by detailed conventional biochemical methods, fatty acid methyl ester (FAME) analysis and partial 16S rDNA sequencing. Analysis of the data revealed that Bacillus pumilus was the most predominant species in the region under study followed by B. cereus and B. sphaericus. The B. pumilus isolates were further characterized by arbitrarily primed PCR (AP-PCR), antibiotic sensitivity profiling and PCR screening for known toxin genes associated with Bacillus spp. All B. pumilus isolates were biochemically identical, exhibited high protease and lipase activity and uniformly sensitive to antibiotics tested in this study. One strain of B. pumilus harboured cereulide synthetase gene cesB of B. cereus which was indistinguishable from rest of the isolates biochemically and by AP-PCR. This study reports, for the first time, the presence of the emetic toxin gene cesB in B. pumilus.

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Section: Discussionmentioning

confidence: 99%

Biochemical and molecular characterization of Bacillus pumilus isolated from coastal environment in Cochin, India

Parvathi¹,

Krishna²,

Jose³

et al. 2009

Braz. J. Microbiol.

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“…DNA fragments of emetic and emetic-like strains were subcloned in Topo TA vector (Invitrogen) and sequenced as described previously (Ehling-Schulz et al, 2004b). The resulting sequences were searched against the sequenced genomes of B. cereus group strains and against the NCBI non-redundant protein database using BLAST (Altschul et al, 1990).…”

Section: Methodsmentioning

confidence: 99%

Emetic toxin formation of Bacillus cereus is restricted to a single evolutionary lineage of closely related strains

Svensson²,

et al. 2005

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An in-depth polyphasic approach was applied to study the population structure of the human pathogen Bacillus cereus. To assess the intraspecific biodiversity of this species, which is the causative agent of gastrointestinal diseases, a total of 90 isolates from diverse geographical origin were studied by genetic [M13-PCR, random amplification of polymorphic DNA (RAPD), multilocus sequence typing (MLST)] and phenetic [Fourier transform Infrared (FTIR), protein profiling, biochemical assays] methods. The strain set included clinical strains, isolates from food remnants connected to outbreaks, as well as isolates from diverse food environments with a well documented strain history. The phenotypic and genotypic analysis of the compiled panel of strains illustrated a considerable diversity among B. cereus connected to diarrhoeal syndrome and other non-emetic food strains, but a very low diversity among emetic isolates. Using all typing methods, cluster analysis revealed a single, distinct cluster of emetic B. cereus strains. The isolates belonging to this cluster were neither able to degrade starch nor could they ferment salicin; they did not possess the genes encoding haemolysin BL (Hbl) and showed only weak or no haemolysis. In contrast, haemolytic-enterotoxin-producing B. cereus strains showed a high degree of heterogeneity and were scattered over different clusters when different typing methods were applied. These data provide evidence for a clonal population structure of cereulide-producing emetic B. cereus and indicate that emetic strains represent a highly clonal complex within a potentially panmictic or weakly clonal background population structure of the species. It may have originated only recently through acquisition of specific virulence factors such as the cereulide synthetase gene.Abbreviations: FTIR, Fourier transform Infrared; Hbl, haemolysin BL; MLST, multilocus sequence typing; Nhe, non-haemolytic enterotoxin; RAPD, random amplification of polymorphic DNA.The GenBank/EMBL/DDBJ accession numbers for the sequences of the internal gene fragments used for MLST and for the sporulation stage III AB genes reported in this paper are AY762151-AY762213 and AY578317-AY578349, respectively.

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“…systems have been developed for the identification of emetic strains and the detection of the toxin gene Ehling-Schultz et al, 2004Altayar and Surtherland, 2006 . However, the conventional PCR requires post-PCR analysis by gel electrophoresis and visualization steps, which take valuable time and may bear the risk of giving false-positive results due to laboratory contamination.…”

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Detection of Emetic Bacillus cereus by Real-Time PCR in Foods

et al. 2013

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The simplex real-time PCR assays based on the TaqMan probe and SYBR green I which target cereulide synthetase genes ces genes were used for rapidly, reliably and sensitively identifying the emetic strains from among Bacillus cereus strains isolated from different sources. Only the emetic strains showed positive reactions to the real-time PCR assays, but all examined strains of diarrheal B. cereus, other Bacillus species and other gram positive and negative bacteria gave negative results. The final identification of emetic B. cereus was possible within 1 to 1.5 h in both simplex real-time PCR procedures. The detection limit of emetic strains in food was suggested to be 10 4 -10 5 cfu/g. Both simplex real-time PCR assays were found to be rapid, sensitive and reliable diagnostic tools that complement the different cellular, immunological and chemical detection methods for cereulide-producing B. cereus, even if a relatively expensive device is required for the assays.

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Identification of emetic toxin producingBacillus cereusstrains by a novel molecular assay

Cited by 166 publications

References 29 publications

Biochemical and molecular characterization of Bacillus pumilus isolated from coastal environment in Cochin, India

Biochemical and molecular characterization of Bacillus pumilus isolated from coastal environment in Cochin, India

Emetic toxin formation of Bacillus cereus is restricted to a single evolutionary lineage of closely related strains

Detection of Emetic Bacillus cereus by Real-Time PCR in Foods

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