• Journal of Environmental Health Sciences
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• v.31 no.1
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• pp.23-30
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• 2005

Staphylococcus aureus is one of the important pathogenic agents, which are related to the hygienic condition. This study performed for the detection of Staphylococcus aureus and screening staphylococcal enterotoxin a, b, c genes in strains isolated from the environment for production of non-pasteurized strawberry juice. A total of 44 samples were collected from utensils, machinery, employees, raw materials, and strawberry juices in 3 strawberry juice shops in Jinju, western Gyeongnam. The isolation rate of Staphylococcus aureus was 26%. Specially Staphylococcus aureus was frequently isolated from employee's hands, strawberry and strawberry juices. The sea, seb, and sec genes were also investigated by polymerase chain reaction (PCR). One hundred and 55% of each isolate had found sea gene and seb gene, respectively. However, sec gene was not detected anywhere. To prevent food-borne disease associated with juice, the accomplishment of HACCP to be more efficient and systematic is necessary.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2043-2048
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• 2015

Bacillus thuringiensis microbial insecticide products have been applied worldwide. Although a few cases of B. thuringiensis foodborne illness have been reported, little is known about the toxigenic properties of B. thuringiensis isolates. The aims of this study were to estimate the pathogenic potential of B. thuringiensis selected from microbial insecticide products, based on its possession of toxin genes and production of enterotoxins. Fifty-two B. thuringiensis strains selected from four kinds of microbial insecticide products were analyzed. PCR assay for detection of toxin genes and immunoassay for detection of enterotoxins were performed. The hemolysin BL complex as a major enterotoxin was produced by 17 (32.7%), whereas the non-hemolytic enterotoxin complex was detected in 1 (1.9%) of 52 B. thuringiensis strains. However, cytK, entFM, and ces genes were not detected in any of the tested B. thuringiensis strains. The potential risk of food poisoning by B. thuringiensis along with concerns over B. thuringiensis microbial insecticide products has gained attention recently. Thus, microbial insecticide products based on B. thuringiensis should be carefully controlled.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1449-1456
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• 2017

The prevalence and toxin characteristics of Bacillus thuringiensis isolated from 39 organic vegetables were investigated. B. thuringiensis was detected in 30 out of the 39 organic vegetables (76.9%) with a mean value of 2.60 log CFU/g. Twenty-five out of the 30 B. thuringiensis isolates (83.3%) showed insecticidal toxicity against Spodoptera exigua. The hblCDA, nheABC, and entFM genes were found to be the major toxin genes, but the ces gene was not detected in any of the tested B. thuringiensis isolates. The hemolysin BL enterotoxin was detected in all 30 B. thuringiensis isolates (100%). The non-hemolytic enterotoxin complex was found in 27 out of 30 B. thuringiensis isolates (90.0%). The B. thuringiensis tested in this study had similar toxin gene characteristics to B. cereus, which possessed more than one toxin gene. B. thuringiensis could have the potential risk of foodborne illness based on the toxin genes and toxin-producing ability.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.219-224
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• 2020

The purpose of this study was to provide basic data necessary for the prevention of food poisoning and safe food management. We examined 872 food samples for B. cereus in accordance with the MFDS Food Code and investigated characteristics of their harboring toxin genes. We detected and isolated 113 strains of B. cereus from 78 food samples (8.9%), and the average detection level was 48 CFU/g. B. cereus isolates carried at least 1 toxin gene among the emetic toxins and 5 enterotoxin genes. The toxin gene profiles of B. cereus were classified into 18 different types of isolates showing genetic diversity. Among the strains, 34 (30.1%) had all 5 enterotoxin genes (Cytk-nheA-entFM-bceT-hblC), accounting for the highest percentage. The entFM and nheA genes were major enterotoxin genes, while the emetic toxin gene, CER, was the least detected in B. cereus isolated from food samples.

• Journal of Food Hygiene and Safety
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• v.23 no.4
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• pp.343-347
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• 2008

Recently, Sunshik has been issued because of easy-cook and well-being food. Sunshik basically was made of the heated cereals. Amount of spore-forming Bacillus cereus was detected and it has been caused some problem of food safety. B. cereus was isolate from 57 out of 161 Sunshik samples resulting in the isolation rate of 35.4%. Quantitative analysis of 57 samples showed that 21 samples were less than 100 CFU/g, 33 samples were between 100 and 1,000 CFU/g and distinctively even 3 (1.9%) samples had over 1,000 CFU/g. Typical morphology of B. cereus isolated from Sunshik was observed on MYP agar and then further characteristics was identified by using VITEK 2 (Biomeriux, France). 53 strains out of 57 strains isolated from Sunshik (about 93.0%) produced diarrheal enterotoxin in brain heart infusion broth which was detected by the Bacillus cereus enterotoxin reversed passive latex agglutination test kit (Oxoid England). The D-values of the B. cereus spores were $75^{\circ}C$ (37.1mim), $80^{\circ}C$ (22.5mim), $85^{\circ}C$ (4.9mim), and $90^{\circ}C$ (3.1mim) respectively. The Z-value was calculated $12.8^{\circ}C$ in Sunshik sample inoculated with B. cereus. Therefore, the management of B. cereus in Sunshik is required for the food-safety.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.425-429
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• 2009

Identification of virulent Bacillus cereus strains was examined by PCR using primers specific for the detection of plcR-papR, which encode regulatory proteins controlling the transcription of virulence factors in B. cereus. Total 96 strains of B. cereus that carried at least one of diarrheal toxin genes including hblACD, nheABC, and cytK showed all positive PCR products, while other 48 Bacillus strains that lacked the toxin genes were plcRpapR-negative. This PCR method targeting the plcR-papR genes appears to be simple and effective in identifying the enterotoxin genes-harboring B. cereus strains.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.50-56
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• 2017

The purpose of this study was to investigate the microbiological contamination of water and drinking cups in springs and to estimate the toxin gene, enterotoxin production ability and antibiotic susceptibility of foodborne pathogens. Ten spring water and 34 drinking cups were tested. The average number of total aerobic bacteria and coliform bacteria in spring water were 1.8 log CFU/mL and 1.2 log CFU/mL, and in drinking cups were $4.7log\;CFU/100cm^2$ and $1.7log\;CFU/100cm^2$. Salmonella spp., Staphylococcus aureus, E. coli O157:H7, Listeria monocytogenes, Vibrio parahaemolyticus, Yersinia enterocolitica were not isolated from all of samples but Bacillus cereus was detected in 5 (14.7%) of 34 drinking cups. The nheA and entFM genes were major enterotoxin genes in B. cereus isolated from drinking cups. All of B. cereus tested in this study produce non-heamolytic enterotoxin but only 2 isolates possessed heamolysin BL enterotoxin producing ability. B. cereus was resistant to ${\beta}-lactam$ antibiotics. These results revealed that the sanitary conditions of drinking cups in spring should be improved promptly. The substitution carrying a personal drinking cup for the public drinking cups equipped in springs is suggested to prevent food-borne illness.

• Korean journal of food and cookery science
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• v.28 no.5
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• pp.599-604
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• 2012

In this study, the prevalence of microbiological hazard on water purifiers at lunchroom in child care center was investigated. A total of 49 water purifiers and their purified cold water were sampled to test about the total aerobic bacteria, coliform bacteria, Bacillus cereus, Staphylococcus aureus, and Salmonella spp. Total aerobic bacteria was detected over 2.0 log CFU/mL in 6 out of 49 purified cold water (12.2%), ranged from 2.0 to 2.4 log CFU/mL, and the average number of total aerobic bacteria was showed to be 3.3 log CFU/drain spout. The drain spout turned out to be a major contaminant in water purifier and needs to be improved. Coliform bacteria were also detected in 7 out of 49 cold faucets (14.3%) and 7 out of 49 drain spouts (14.3%), but not detected in purified cold water. All samples were not contaminated with the pathogens tested in this study, except for B. cereus, which was contaminated on 2 out of 49 cold faucets (4.1%) and 4 out of 49 drain spouts (8.2%). All of B. cereus isolates produced enterotoxin, such as heamolysin BL enterotoxin (HBL) or non-heamolytic enterotoxin (NHE). The HBL was detected in 5 out of 6 B. cereus isolates (83.3%), including B. cereus PCF-11 and B. cereus PDS-30 isolate only produced NHE (16.7%). These results showed that the sanitary conditions of cold faucets and drain spouts should be improved promptly.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.709-717
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• 2017

Mucosal tissues are the initial site through which most pathogens invade. As such, vaccines and adjuvants that modulate mucosal immune functions have emerged as important agents for disease prevention. Herein, we investigated the immunomodulatory mechanisms of the B subunit of Escherichia coli heat-labile enterotoxin type IIa ($LT-IIa-B_5$), a potent non-toxic mucosal adjuvant. Alternations in gene expression in response to $LT-IIa-B_5$ were identified using a genome-wide transcriptional microarray that focused on dendritic cells (DC), a type of cell that broadly orchestrates adaptive and innate immune responses. We found that $LT-IIa-B_5$ enhanced the homing capacity of DC into the lymph nodes and selectively regulated transcription of pro-inflammatory cytokines, chemokines, and cytokine receptors. These data are consistent with a model in which directional activation and differentiation of immune cells by $LT-IIa-B_5$ serve as a critical mechanism whereby this potent adjuvant amplifies mucosal immunity to co-administered antigens.

• Biomedical Science Letters
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• v.20 no.2
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• pp.96-102
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• 2014

Staphylococcal enterotoxin B (SEB) is bacterial toxin that induces the activation of immune cells. Because the inhibition of pro-inflammatory effect of SEB can resolve the inflammation, I determined the influence of functional or structural change of SEB on immune cells. The post translational modification of protein occurs through carbamylation. Carbamylation can change the structure of proteins and can modify the biological activity of protein. In the present study, I investigated the effect of carbamylated SEB (CSEB) on the inflammatory response mediated by LPS in HL-60 cells. To determine the anti-inflammatory effect of CSEB, I produced carbamylated SEB using potassium cyanate (KCN) and then examined whether CSEB involved in cytokine releases and apoptosis of LPS-stimulated HL-60 cells. Although CSEB had not any effect on the LPS-stimulated HL-60 cells, the protein levels of IL-8, TNF-${\alpha}$ and IL-$1{\beta}$ were significantly decreased by CSEB without cytotoxicity. CSEB also blocked Akt and NF-${\kappa}B$ activation. These results indicate that the suppressive effect of CSEB in LPS-stimulated cytokine releases is occurred by inhibition of Akt and NF-${\kappa}B$ activity. Through further studies, CSEB may be used as anti-inflammatory molecule that makes the immune system more efficient.