• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.55-63
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• 1985

Phosphate, ammonia, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate were examined for their ability to control the heat-stable enterotoxin (ST) production in succinate salts medium or in M9 medium. The results obtained were summerized as follows. 1. When the initial phosphate concentration was adjusted to 1.0mM, ST production was decreased to 80u/ml or less. But when the initial phosphate concentration was adjusted to 64mM or 100mM, enterotoxin production was 320u/ml. 2. When the initial ammonia concentration in the medium was adjusted to 1.0mM, no ST production and cell growth were observed. But when ammonia concentration was adjusted to 10mM, 19mM, 38mM or 76mM, enterotoxin production was 320u/ml. 3. Among carbon sources, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate, acetate supported the highest specific production (928 unit/O.D.) of heat-stable enterotoxin. From this results, we could assume that heat-stable enterotoxin production is controlled by stringent control mechanism. 4. When the pH of the succinate salts medium was kept between 6.2 to 6.5, no heat-stable enterotoxin production was observed, but when the pH of the medium was kept between pH 6.2 to 6.5, 267 unit/O.D. of heat-stable enterotoxin was produced. 5. Glucose inhibited the heat-stable enterotoxin production and the mechanism was assumed due to its capacity to lower the pH of the medium during catabolysis and its high metabolic energy.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.824-828
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• 2008

Effect of various temperatures on enterotoxin production of Bacillus cereus 4 different cereal grains (brown rice, glutinous rice, barley, and Job's tear) was studied. When B. cereus was inoculated to 4 grains, no toxin was detected within 24 hr at 20 and $25^{\circ}C$ although the population reached approximately 8-10 log CFU/g. However, enterotoxin was detected in all samples above $30^{\circ}C$. When the temperature was increased to $35^{\circ}C$, toxin production was observed in the range of 6.11 and 6.26 log CFU/g on brown rice and glutinous rice, respectively. At $40^{\circ}C$, toxin production was detected after 6 hr with the lowest bacterial population of 5.32 and 5.04 log CFU/g, whereas enterotoxin was produced in the range of 6.86 and 7.77 log CFU/g on barley and Job's tear at $40^{\circ}C$. Different types of food affected enterotoxin production of B. cereus. These results suggest that enterotoxin production was more significantly regulated in incubation temperatures than the number of B. cereus.

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

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

• Korean Journal of Veterinary Service
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• v.23 no.4
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• pp.313-320
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• 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 Clinical Laboratory Science
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• v.37 no.1
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• pp.27-34
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• 2005

Biochemical characteristics, enterotoxin production and antimicrobial susceptibility were determined for 30 strains of Bacillus cereus isolated from stool specimens of diarrhea patients at an university hospital in Chulabuk-do province. Positive rate for VP reaction and citrate utilization were lower, (33 % and 40 % respectively) while the rates of acid production from mannitol, arabinose, and xylose were higher (17 %, 13 % and 3 % respectively) than those obtained by other investigators. The enterotoxin gene was detected in 18 of 30 isolates (60 %) by PCR, and the toxin was detected from all of the toxin gene-positive isolates by RPLA test. The agar dilution test showed that all isolates were resistant to penicillin G and 73 % were to cephalothin, but all were susceptible to ciprofloxacin, clindamycin, erythromycin, fusidic acid, gentamicin, rifampin, teracycline and vancomycin. We conclude that B. cereus isolates producing acid from mannitol, arabinose and xylose exist, that PCR can be used to detect enterotoxin genes rapidly and accurately, and that this organism is susceptible to various antimicrobial agents though not penicillin G and cephalothin.

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

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

• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.59-65
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• 1988

This paper deals with the 0 groups of citrate utilizing variants of Escherichia coli ($Cit^+$ E. coli) isolated from cattle, the production of colicin, hemolysin, K99 antigen, heat stable enterotoxin, and the isolation of plasmid DNA. Among 42 $Cit^+$ E. coli, 12 strains were 020, 9 strains 08, 5 strains 045, 3 strains 0115, 1 strain 064, 1 strain 0139 and remaining strains(11) were untypable. Thirty-nine(81.3%) out of 48 $Cit^+$ E. coli were produced colicin and 13(27.0%) were produced hemolysin. Of 12 $Cit^+$ E. coli bearing K99 antigen, 6(50.0%) were produced heat stable enterotoxin. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmids varied from 1 to 7 in 10 $Cit^+$ E. coli. It's molecular weight ranged from 2 to 50 Mdalton, and 50 Mdalton plasmid was commonly existed in all strains.

• Korean Journal of Microbiology
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• v.16 no.4
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• pp.161-169
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• 1978

Escherichiae-like organisms were isolated from rectal specimens of 56 children who were either in preschool age or in elementary school. The isolated strains were subjected to tests to screen enteropathogens producing heat-labile enterotoxin and susceptibility test to various antibiotics by disc diffusion method on agar plates. Production of heat-labile enterotoxin by the strains was assyed in the sensitive and reproducible cultured adrenal tumor cell system. The assay was sterodogenesis of the cell in the presence of heat-labile enterotoxin. Among 56 strains, gave positive reaction in the test of toxin production. This meant that about 10% of the children population objected to the study harbored the toxigenic strain of enteropathogenes. Some of these toxigenic strains were resistant to the antibiotics employed in the test. This study suggested that considerable population in Korea may harbor entertoxigenic E. coli as a part of intestinal normal flora. The toxigenic strains which are resistant to antibiotics may bring issue of public health in the future.