• Korean Journal of Microbiology
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• v.39 no.1
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• pp.40-44
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• 2003

Bacillus anthracis is a gram-positive spore-forming bacterium that causes the disease anthrax. In order to develop a DNA marker specific for Bacillus anthracis and to discriminate this species from Bacillus cereus group, we applied the randomly amplified polymorphic DNA (RAPD)-PCR technique to a collection of 29 strains of the genus Bacillus, including 22 species of the B. cereus group. A 709-bp RAPD marker (KHT5) specific for B. anthracis was obtained from B. anthracis BAK. The PCR product of internal primer set from the KHT5 fragment distinguished B. anthracis from the other species of the B. cereus group.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.232-237
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• 2006

Bacillus cereus group comprising B. cereus, B. thuringiensis, and B. mycoides was differentiated by polymerase chain reaction (PCR) and colony morphology. Prevalence of B. cereus group in rice and distribution of enterotoxin genes were determined as possible food poisoning agents. PCR using primers targeted for gyrB and cry genes could distinguish B. thuringiensis from B. cereus, and B. mycoides was differentiated by rhizoid morphological characteristics on nutrient agar. Among 136 rice and their processed products, prevalence of B. cereus group was 40%. B. cereus group consisted of 54 B. cereus, 11 B. thuringiensis, and 1 B. mycoides. Major isolates were B. cereus, with B. thuringiensis detected up to 10% among edible rice tested. Five enterotoxin genes, hbl, nhe, bceT, entFM, and cytK, were broadly distributed among B. cereus group, especially in B. cereus and B. thuringiensis. Prevalence of B. cereus group in rice and enterotoxin distribution suggest B. thuringiensis and B. cereus are toxigenic strain that should be controlled in rice and its products.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1177-1182
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• 2007

Bacillus cereus group bacteria share a significant degree of genetic similarity. Thus, to differentiate and identify the Bacillus cereus group efficiently, a multiplex PCR method using the gyrB and groEL genes as diagnostic markers is suggested for simultaneous detection. The assay yielded a 400 bp amplicon for the groEL gene from all the B. cereus group bacteria, and a 253 bp amplicon from B. anthracis, 475 bp amplicon from B. cereus, 299 bp amplicon from B. thuringiensis, and 604 bp amplicon from B. mycoides for the gyrB gene. No nonspecific amplicons were observed with the DNA from 29 other pathogenic bacteria. The specificity and sensitivity of the B. cereus group identification using this multiplex PCR assay were evaluated with different kinds of food samples. In conclusion, the proposed multiplex PCR is a reliable, simple, rapid, and efficient method for the simultaneous identification of B. cereus group bacteria from food samples in a single tube.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.657-663
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• 2011

$Bacillus$ $cereus$ is widely distributed on various foods and is known to cause clinical infections, food poisoning toxin induced diarrhea and vomiting. In this study, $B.$ $cereus$ group detected and analyzed rice, rice bran, and biofilm characterization of $B.$ $cereus$ confirmed. $B.$ $cereus$ was identified in approximately 34.6% of brown rice and 50.0% of rice bran. $B.$ $thuringiensis$ was detected in 3.9% of brown rice and 23% of rice bran, and $B.$ $mycoides$ was isolated from rice bran. The microtiter plate assay detected differences in biofilm-forming ability among $B.$ $cereus$ group isolates. Biofilm of $B.$ $cereus$ seemed to increase the MIC values of antimicrobial agent and antibiotic compounds compared with planktonic cells. Therefore, sufficient attention should be given to good manufacturing practice and good agriculture practice to avoid contamination of $B.$ $cereus$ group raw material including rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1842-1846
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• 2012

The effects of hurdle techniques on the reduction of Bacillus cereus spores in Doenjang and Gochujang were investigated. In our system, Bacillus cereus spores were artificially inoculated into Doenjang and Gochujang. Hurdle techniques used in this study were additives (3% ethyl alcohol-0.03% oregano extract), Joule heating ($95^{\circ}C$ for 5 min), and hydrostatic pressure (500 MPa for 5 min at $45^{\circ}C$). Additive-Joule (AJ) and additive-Joule-pressure (AJP) treatments for Doenjang resulted in a 2.80 log and 3.74 log reduction, respectively, while treatments for Gochujang resulted in a 4.71 log and 5.60 log reduction, respectively. This suggests a high synergistic effect of Joule heating with additive treatment in Doenjang and Gochujang. A combination ofg hurdles such as additives, Joule heating, and hydrostatic pressure also kept Bacillus cereus spore counts low during storage at $30^{\circ}C$. Therefore, Bacillus cereus spores inoculated into Doenjang and Gochujang can be effectively reduced through combined treatments, including AJ or AJP.

• Bulletin of Food Technology
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• v.22 no.3
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• pp.587-600
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• 2009

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.339-346
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• 1992

These studies were carried out to identify Bacillus cereus group 1..5-] strain isolated from 5uyeong Bay. This strain was differentiated from B. cereus group using conventional, API system and fatty acid composition analysis. Colony characteristics were opague. mucoid, entire margin. convex. circular and non hemolysis on sheep blood agar plates, and were observed with central spore forming positive bacilli in a Gram stained preparation. and had no motility. The carbohydrates tested; glucose.maltose, and sucrose were assimilated but neither trehalose nor salicin were assimilated. This strain ultilized gelatin and was also inhibited by 6.5% NaCI. The results of biochemical examination were differented from B. cereus group LS-1 compared with others B. cereus group. The fatty acid composition contained major amounts of branched chain acids. iso $C_{15}$ and iso $C_{13}$ and the range of chain length was $C_{12}$ to C"$C_{17}$ and n$C_{15}$, acid was not detected. Automated fatty acid computer profile indicated "B. mycoides GC subgroup B of 0.312 similarity index." The results agreed with other research cases. On the other hand. A TB computer prolile index of API system (API 50 CHB & API 20E) identified" Doubtful profile of 99.7% B. firmus" . These results were presented with considerable discrepancies between API system and fatty acid analysis. With 67 biochemical characters. the similarity matrix of B. mycaides (KCTC 1033). B. thuringiensis (KCTC 1033). B. cereus (5-3) and B. mycoides (S-12) showed 42%. 42%. 59%, and 52%. respectively. Through the key tests and fatty acid analyses. we could notice the appearance of B. mycoides of the B. cereus group and this leads us to suspect the existence of a new biotype B. mycoides.

• Genomics & Informatics
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• v.21 no.3
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• pp.35.1-35.12
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• 2023

The Bacillus cereus group, also known as B. cereus sensu lato (B. cereus s.l.), is composed of various Bacillus species, some of which can cause diarrheal or emetic food poisoning. Several emerging highly heat-resistant Bacillus species have been identified, these include B. thermoamylovorans, B. sporothermodurans, and B. cytotoxicus NVH 391-98. Herein, we performed whole genome analysis of two thermotolerant Bacillus sp. isolates, Bacillus sp. B48 and Bacillus sp. B140, from an omelet with acacia leaves and fried rice, respectively. Phylogenomic analysis suggested that Bacillus sp. B48 and Bacillus sp. B140 are closely related to B. cereus and B. thuringiensis, respectively. Whole genome alignment of Bacillus sp. B48, Bacillus sp. B140, mesophilic strain B. cereus ATCC14579, and thermophilic strain B. cytotoxicus NVH 391-98 using the Mauve program revealed the presence of numerous homologous regions including genes responsible for heat shock in the dnaK gene cluster. However, the presence of a DUF4253 domain-containing protein was observed only in the genome of B. cereus ATCC14579 while the intracellular protease PfpI family was present only in the chromosome of B. cytotoxicus NVH 391-98. In addition, prophage Clp protease-like proteins were found in the genomes of both Bacillus sp. B48 and Bacillus sp. B140 but not in the genome of B. cereus ATCC14579. The genomic profiles of Bacillus sp. isolates were identified by using whole genome analysis especially those relating to heat-responsive gene clusters. The findings presented in this study lay the foundations for subsequent studies to reveal further insights into the molecular mechanisms of Bacillus species in terms of heat resistance mechanisms.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.361-367
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• 2010

Bacterial contamination of cooked rice was analyzed to evaluate the microbial safety. Thirty raw rice samples were collected in Korea and cooked in an electric rice cooker. Mesophilic aerobe, food-poisoning Bacillus cereus group, and their toxin genes were determined on cooked rice. The percentage of total mesophilic aerobe based on 1-3 log CFU/g was 27% among the samples. Bacillus spp. in MYP selective medium was similar to the number of mesophilic aerobe, whileas Bacillus spp. was detected in most samples after enrichment. Thirty-seven isolates from 30 cooked rices were identified as B. thuringiensis, B. cereus, B. valismortis, B. pumilus, B. coagulans, B. licheniformis, Geobacillus stearothermophilus, and Brevibacillus laterosporus. Twenty isolates (54%), more than half of the isolates, were B. thuringiensis while nine (27%) were identified as B. cereus. All B. thuringiensis isolates possessed non-hemolytic toxin genes and interestingly, seven B. cereus among nine isolates possessed emetic toxin genes. More B. thuringiensis was present on the cooked rice than B. cereus and most B. cereus possessed emetic toxin genes rather than diarrheal toxin genes. Therefore, food-borne outbreak due to B.cereus on the cooked rice kept at room temperature might be examples of emetic food-poisoning.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.333-338
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• 2008

Computational analysis of partial rpoB gene sequence (777 bp) was done in this study to identify B. anthracis and its closely related species B. cereus and B. thuringiensis. Sequence data including 17 B. anthracis strains, 9 B. cereus strains, and 7 B. thuringiensis strains were obtained by searching databases. Those sequences were aligned and used for other computational analysis. B. anthracis strains were identificated by in silico restriction enzyme digestion. B. cereus and B. thuringiensis were not segregated by this method. Those sequencing and BLAST search were required to distinguish the two. In actual identification tests, B. anthracis strains could be identified by PCR-RFLP, and B. cereus and B. thuringiensis strains were distinguished by BLAST search with reliable e-value. In this study fast and accurate method for identifying three Bacillus species, and flow chart of identification were developed.