• Korean Journal of Food Science and Technology
• /
• v.20 no.6
• /
• pp.856-861
• /
• 1988

A new method developed for simultaneous purification of enterotoxin A and C from Staphylococcus aureus strain L 350/1 consisted of chromatography on carboxymethyl (CM)-cellulose using a buffer of variable pH, gel filtration on Ultro gel, and fast protein liquid chromatography(FPLC) using a buffer of variable pH. The enterotoxin A and C were purified by three steps: batchwise adsorption from culture supernatant on Amberlite CG-50; chromatography on CM-cellulose using a buffer of constant pH and molarity; and gel filtration on Sephadex G-75. The purified enterotoxin appeared homogeneous by gel diffusion and polyacrylamide gel electrophoresis. Upon treatment with CM-cellulose using a elution of variable pH, enterotoxin A and C were so close that they were not separated completely. After elution from gels, the enterotoxins appeared as a single peak at the same position. Gel filtration gave a reaction of complete identity to enterotoxin A and C in Ouchterlony immunodiffusion. In FPLC using a CM-cellulose, enterotoxin A and C were simultaneously separated at pH 8.6 and 6.8. When each fraction was performed to gel immunodiffusion, at peak of enterotoxin A and C were not detected each other. In a method of elution by pH-gradient was to be more efficient as a simultaneous separation method in terms of speed, yields and simplicity. The purified toxin A and C were identical to type A and C reference enterotoxin on both disc electrophoresis and Ouchterlony gel diffusion.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.1
• /
• pp.1-5
• /
• 2000

Detection for heat-labile enterotoxin(LT) of enterotoxigenic Escherichia coli(ETEC, EC81, O148:H28) and enterotoxin of enterotoxigentic Clostridium perfringents type A(CP, NCTC8238, Hobbs serotype 2) by use of a polymerase chain reaction (PCR) assay were positive reaction, which using LT gene-specific primers of ETEC with a detection limit equivalent from 100ng/${\mu}\ell$ to 1 pg of a DNA fragment of 417-bp in EC81 and enterotoxin gene-specific primers of CP with a detection limit equivalent from 100ng/${\mu}\ell$ to 10pg of a DNA fragment of 364-bp in NCTC8238. Detection for a LT gene of ETEC highly appeared 10-fold sensitivity than an enterotoxin gene of CP.

• Korean Journal of Veterinary Service
• /
• v.23 no.4
• /
• pp.313-320
• /
• 2000

Staphylococcus aureus is a causative pathogen of bovine mastitis. It is recognized as a common pathogen in human and animal and specially enterotoxin-producing strain of S aureus is a common cause of staphylococcal food poisoning in human. Various food originated raw milk, cheese, butter produced from mastitic cow causes staphylococcal food poisoning. It is difficult to treat the staphylococcal mastitis because of increasing resistance by using overdose of antibiotics. This study was conducted to investigate the enterotoxin-production and coagulase serotypes of S aureus in Chonnam province for 6 month, 1999. Also we studied the antibiotic resistant pattern with 14 types against isolates. 18(10.1%) S aureus were isolated from 178 raw milk samples in seven farms. and 8 strains(38%) were isolated in 21 raw milk samples which was below 500,000 somatic cells. We identify that 7(87.5%) of 8 isolates and 15(83.3%) 18 isolates produce enterotoxin. Their enterotoxin serotype was type B(66.7%), type A(33.3%) and type C(13.3%). Also 2 strains of isolates was positive to the type A and B. Coagulase serotype of isolates was 2, 3, 4, 7, and 8. Most stains(70.6%) were serotype 2. And most strains(17 isolates, 94.4%) except one isolate was multiple resistant to the tested antibiotics.

• Korean Journal of Food Science and Technology
• /
• v.23 no.2
• /
• pp.150-156
• /
• 1991

This research was conducted to investigate the effect of starter culture(Lactobacillus plantarum), glucono-delta-lactone(GdL), and NaCl on the production of staphylococcal enterotoxin A in the processing of fermented sausages. With the increasing amount of GdL(0, 0.23, 0.50 and 0.75%) added the production of enterotoxin was significantly decreased(p>0.01). Lactobacillus plantarum as starter culture were inoculated at the level of $10^6\;cells/g$. When GdL was not added, the amount of production of enterotoxin in the group with and without the starter culture were 40 and 80 ng/10g, respectively. With the addition of 0.5%, GdL, the maximum amount of enterotoxin produced in the group with and without starter culture were 30 and 50 ng/10g. These results showed the inhibiting effect of starter culture in the production of enterotoxin. When the amount of enterotoxin production was compared with the addition of 2.7 and 1.7% NaCl, the production of enterotoxin was higher at 2.7% NaCl level.

• Food Science and Biotechnology
• /
• v.17 no.4
• /
• pp.761-765
• /
• 2008

Bacillus cereus causes two different types of food poisoning syndromes: diarrhea and emesis. The diarrheal syndrome is attributed to various enterotoxins, including nonhemolytic enterotoxin, hemolytic enterotoxin, and enterotoxin-T, whereas the emetic syndrome is caused by the dodecadepsipeptide toxin cereulide. A multiplex polymerase chain reaction (PCR) assay was developed to rapidly detect and identify B. cereus strains. Three primer pairs specific to regions within genes encoding nonhemolytic enterotoxin (nheA), molecular chaperonin (groEL), and cereulide synthetase (ces) were used to identify and differentiate between the enterotoxin-producing and emetic toxin-producing B. cereus strains. The cereulide-producing emetic B. cereus showed 3 PCR products of 325, 405, and 685 bp for the groEL, ces, and nheA genes, respectively, whereas the enterotoxin-producing B. cereus showed 2 PCR products without a ces gene specific DNA fragment. Specific amplifications and differentiations by multiplex PCR assay were obtained using 62 B. cereus strains and 13 strains' of other bacterial species. The detection limit of this assay for enterotoxin-producing strain and emetic toxin-producing strain from pure cultures were $2.4{\times}10^1$ and $6.0{\times}10^2\;CFU/tube$, respectively. These results suggest that our multiplex PCR method may be useful for the rapid detection and differentiation of B. cereus strains in foods.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.461-467
• /
• 2007

Staphylococcus aureus strains are important foodborne pathogens that produce various toxins. To evaluate the risk of the enterotoxins, four S. aureus strains from kimbap and two clinical samples were isolated and identified, and their expression of the enterotoxin genes were analyzed using a reverse transcription real-time PCR. Various enterotoxin genes were detected, including sea, seg, seh, sei, sen, seo, and sem, where each isolate contained one or two. When the mRNA detection of the enterotoxin genes was analyzed using a reverse transcriptase PCR, various levels of expression were found depending on the species and enterotoxin gene. Therefore, it is reasonable to suggest that the poisoning risk of S. aureus can be effectively evaluated based on the gene expression at the mRNA level.

• Journal of Radiation Industry
• /
• v.7 no.2_3
• /
• pp.161-166
• /
• 2013

The purpose of this study was to investigate the cell proliferating and interleukin-2 producing activity of staphylococcal enterotoxin B by gamma-irradiation. Staphylococcal enterotoxin B was gamma-irradiated with the various doses of 0, 2, 20 and 50 kGy. SDS-PAGE analysis showed that gamma-irradiation caused the sharp decrease of the content of staphylococcal enterotoxin B and the effect was irradiating dose-dependent. Non-irradiated staphylococcal enterotoxin B increased the cell proliferation of splenocytes isolated from female Balb/c mouse, whereas 2 kGy-irradiated toxin significantly decreased the activity. 20 and 50 kGy-irradiated staphylococcal enterotoxin B was no effect. A similar effect on the interleukin-2 production of mouse splenocytes was observed with non-irradiated and irradiated staphylococcal enterotoxin B. It was considered to be due to the decrease of the antigenicity of staphylococcal enterotoxin B by gamma-irradiation. Therefore, these results suggest that gamma-irradiation can be effective for the decrease of the antigenicity of staphylococcal enterotoxin B as superantigen.

• The Journal of the Korean Society for Microbiology
• /
• v.17 no.1
• /
• pp.35-41
• /
• 1982

Enterotoxigenk E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-labile enterotoxin is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a marker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. Therefore knowledge about the heat-labile enterotoxin is essential not only for understanding the pathogenesis but also for the diagnosis of the diarrhea. However the in-vitro heat-labile enterotoxin production is reported to be greatly affected by the cultural condition. In this regards, this study was designed to know the optimal conditions for the production of the heat-labile enterotoxin by assaying the permeability factor in the 18 hours culture supernatant of E. coli 08K25(B2) H9 and of E. coli 015 H11. Results obtained were summerized as follows: 1. Amounts of heat-labile enterotoxin produced were greater at initial pH 8.5 than at 7.0 of CYES-2 broth culture. However, the bacterial growth itself was more abundant at 7.0 than at 8.5. 2. Heat-labile enterotoxin per unit volume of culture supernatant was greater at shaking culture than at standing culture condition, but ratio of the enterotoxin produced over the unit mass of E. coli calculated was greater at standing culture than shaking culture condition, indicating that the greater yields of the toxin produced at shaking culture was due to increase in E. coli cell mass compared to the standing culture condition: 3. The enterotoxin produced in the lincomycin(128 microgram/ml) supplemented media was 5 or 11 times greater on the basis of enterotoxin per unit mass of E. coli, compared to the lincomycin-non-supplemented media, indicating that lincomycin itself increases the enterotoxin production. 4. Treatment of 18 hours culture of E. coli with polymyxin B(0.2 mg/ml) for 1 hour increased the yields of enterotoxin amounting to 2 or 5 times of the non-treated control cultures.

• Journal of Food Hygiene and Safety
• /
• v.6 no.2
• /
• pp.89-93
• /
• 1991

The present study was conducted to investigate the prevalence, the biochemical properties and the enterotoxin types of Staphylococcus aureus in healthy human and patient. A total of 61 S. aureus strains were isolated from 142 samples. The prevalence of S. aureus isolated from healthy human and patient were 17.7% and 14.0%, respectively. All the isolates showed the production of coagulase, lecithinase and hemolysis (${\alpha}-hemolysis;\;32.8%,\;{\beta}-hemolysis;\;67.2%$) on sheep blood agar. Coagulase type VII (38.4%) and type 111 (26.0%) were dominant among coagulase types I through VIII. Twenty-four (52.2%) of 46 strains tested produced one or more enterotoxin; enterotoxin A, Band C were produced by 3, 9 and 12 strains, respectively. Enterotoxins were produced by 100% of type 11 strains, 75% of type 111 and 39.1 % of type VII. Commonly, coagulase type II produced enterotoxin B or C, and type VII produce enterotoxin C.

• Korean Journal of Veterinary Service
• /
• v.25 no.3
• /
• pp.275-283
• /
• 2002

Forty strains of Staphylococcus aureus were isolated from mastitic milk. As a result of antimicrobial susceptibility test, the strains of S aureus revealed 47.5% were resistant to ampicillin and penicillin, and 7.5% to gentamicin. But 45% of isolates were sensitive to antimicrobial agents tested. In case of enterotoxin production, 56.3% of 16 strains produced enterotoxin D. Two strain of enterotoxin D producers produced both enterotoxin B and D. According to isolation date, 15 representative strains were selected. As a results of pulsed field gel eletrophoresis analysis of the 15 representative strains, 14 strains were identical. Therefore we consider the identical strains of S aureus have caused continuously bovine mastitis in this dairy farm. If autogenous vaccine can be made by the strains, it will work well for the prevention of bovine mastitis caused by S aureus.