• 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.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.47-52
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• 1986

A heat-labile enterotoxin and no heat-stable enterotoxin producing($LT^+ST^-$) plasmid (110 kilobases in size) was isolated from an enterotoxigenic Escherichia coli of human strain O15:H11 and used for analysis of the $LT^+$ deoxyrionucleic acid region using recombinant DNA technology. A DNA segment containing the $LT^+$ DNA region which was one restriction endonuclease BamHl fragment(6.2 kb in size) was joind to a small multicopy plasmid, pUC9. E. coli K-12 strain, JM103 harboring the chimeric plasmid produced greater amounts of LT than did the enterotoxigenic E. coli O15:H11 strain. The BamHl fragment was further digested with various restriction endonucleases and contained no HindIll restriction site which is an essential in $LT^+ST^+$ plasmid. The detailed DNA sequencing of this $LT^+ST^-$ plasmid is required.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.621-625
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• 2007

Staphylococcus aureus in Korean kimbab rolls was monitored seasonally in 4 major cities of Korea to investigate the risk of S. aureus in a pre-prepared meal. Thirty-five (28.6%) of 105 kimbab rolls purchased in winter were contaminated with S. aureus with an average level of 2.6 log CFU/g. Thirty-six (33.0%) of 109 kimbab rolls purchased in summer and autumn were contained S. aureus with an average level of 2.9 log CFU/g. Kimbab purchased in snack bars showed higher S. aureus contamination rates with the maximum level of 4.7 log CFU/g than that purchased in convenience stores. Of the raw materials in kimbab, uncooked perilla leaf had the highest contamination rate of S. aureus. Less than 50% of S. aureus isolated from kimbab produced enterotoxin and most of the staphylococcal enterotoxin produced by S. aureus in kimbab was type A.

• Journal of Magnetics
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• v.21 no.1
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• pp.141-147
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• 2016

Staphylococcus aureus cultures exposed to rotating magnetic field (RMF) were studied in order to analyse the possible induced changes in staphylococcal enterotoxin genes (se) expression. Liquid cultures of S. aureus strains carrying different se were exposed to the RMF of magnetic frequency 50 Hz and magnetic induction 34 mT for 10 h at $37^{\circ}C$. Three time points of bacterial growth cycle were considered for RNA extractions. Gene expression analyses were evaluated using real-time quantitative PCR method. The present study confirmed, that the RMF can stimulate the growth rate of S. aureus cultures in comparison to the unexposed controls, while the stimulation is not strain dependent. The studies have also shown, that the RMF, depending on the exposure time but regardless the bacterial strain, can influence on the expression of various se. In general, except for sea, as a result of bacterial exposure to the RMF through subsequent growth phases, the expression of se decreased, reaching the values below results recorded for unexposed controls. In the case of sea expression remained at a lower level as compared to the control, regardless the time of exposition.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.779-784
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• 1997

A comprehensive study of 132 Escherichia coli isolates from 150 piglets with colibacillosis included detection of heat-labile enterotoxin, heat-stable enterotoxin, and identification of K88 (F4), K99 (F5), 987P (F6), and F41. Four pili were examined by haemagglutination and slide agglutination test. Heat-labile(LT) and heat-stable(ST) enterotoxin was determined by reverse passive latex agglutination and precipitation test, respectively. Among 132 E coli isolates, 26 had K88 (19.7%), 16 had K99 (12.1%), 3 had 987P (2.3%), and 2 had F41 (1.5%). Three had K88 and K99 (2.3%), 3 had K88 and 987P (2.3%), 2 had K99 and 987P (1.5%), 5 had K99 and F41 (3.8%), and 8 E coli strains had K88, K99 and F41 (6.1%) simultaneously. Among 132 E coli isolates, 5 produced LT only (3.8%), 55 produced heat-stable toxin ST only (41.7%), and 4 produced both LT and ST (3.0%). Three major pathotypes accounted for 27.9% of E coli isolates: $K99^+$ (8.3%), $K88^+ST^+$ (9%) and $K88^+$ (10.6%). Results of this study indicated that piliated enterotoxin-producing E coli was prevalent and was associated with diarrhea in preweaning piglets.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.273-278
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• 2012

Staphylococcal enterotoxin B (SEB), which is a bacterial superantigen produced by Staphylococcus aureus, is associated with serious diseases, including food poisoning and atopic dermatitis. This study was performed to produce about 30 kDa of recombinant SEB protein and to immunize in chickens to acquire the specific egg yolk antibody (IgY) against the recombinant SEB. Chickens were immunized with the recombinant SEB intramuscularly in the breast muscle by injection 3 times at intervals of two weeks. Serum- and egg yolk-antibody titers of hens against SEB were highest at 4 weeks after first immunization. In western blot, anti-recombinant SEB IgY was reacted immunospecifically against the recombinant SEB and commercialized SEB. These results suggested that the recombinant SEB antigen could be used as an immunogen to elicit antibody (IgY) against SEB and the anti-recombinant SEB IgY could neutralized staphylococcal enterotoxin B effectively.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.671-677
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• 1996

Erythrocytes from three different animal species were used to determine mannose-sensitive hemagglutination (MSHA) and mannose-resistant hemagglutination (MRHA) of 755 isolates obtained from rectal swabs of healthy pig. In addition, colony hybridization using digoxigenin-dUTP labeled polynucleotide probes was performed for the detection of heat-stable and heat-labile enterotoxin genes carried by MRHA positive isolates. Of 755 strains, 9, 4 and 28 strains gave a positive MRHA with bovine, equine and pig erythrocytes, respectively. Of these isolates, 28 (3.7%) were characterized for positive MRHA by at least one blood. Seven isolates gave a positive MRHA with two kinds of blood. Three gave a positive MRHA with three kinds of blood. Twenty-eight strains, while positive in MRHA, yielded negative signals in the colony hybridization assay for the detection of heat-stable (STaI and STaII) and heat-labile (LT) enterotoxin genes in E. coli.

• Biomedical Science Letters
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• v.11 no.3
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• pp.295-299
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• 2005

Staphylococcus aureus is an important animal and human pathogen implicated in a variety of disease including food-poisoning caused by staphyloccal enterotoxins (SEs). In order to investigate the difference in genomic types and to monitor the transmission of S. aureus isolates, a total of 25 S. aureus isolates from different sources were determined for their genotypic characteristics by pulsed-field gel electrophoresis (PFGE) in addition to their ability to enterotoxin production and antibiotic resistance patterns in this study. All the isolates were susceptible to amikacin, and the resistance pattern to ampicillin and penicillin were most common among 14 different patterns. Eleven of 24 isolates produced one of three SEs, SEA, SEC or SED. Sixteen representative PFGE patterns were obtained by Smal restriction fragments of S. aureus isolates. Analysis of dendrogram based on PFGE band patterns suggested that food-poisoning outbreaks be caused by the diverse sources of food, of which their raw materials were infected with S. aureus. Also, it could be concluded that PFGE was a powerful tool for epidemiological tracing of infection source for food-initiated outbreaks.

• Journal of Food Hygiene and Safety
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• v.6 no.2
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• pp.79-81
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• 1991

On May 23, 1990, an acute self-limited gastrointestinal illness was reported by twenty-seven persons. They were some of the employees and family members who attended a company open house picnic in Bergen County, New Jersey. Food questionnaires implicated that ziti was the vehicle of transmission (chi square 9.05). Median incubation period was 9.0 hours, and the median duration of illness 24 hours Clostridium perfringens organisms and enterotoxin were isolated from stool samples.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.598-606
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• 2003

Salmonella encodes an enterotoxin (Stn) which possesses biological activity similar to the cholera toxin. Stn contributes significantly to the overall virulence of S. typhimurium in a murine model. The production of Stn is enhanced in a high-osmolarity medium and by contact with epithelial cells. In the present study, the in vitro and in vivo transcriptional regulations of the sin promoter revealed two promoters, P1 and P2. The P1 promoter identified by a primer extension analysis of stn mRNA exhibited a switching mechanism in vivo. Depending on the growth stage, transcription was initiated from different start sites termed $P1_S\;and\;P1_E$. $P1_S$, recognized by RNA polymerase containing ${\sigma}^S(E{\sigma}^S),\;and\;P1_E$, recognized by $E{\sigma}^70$, were activated during the stationary and exponential phases, respectively, while $P1_S\;and\;P1_E$ were both negatively regulated by CRPㆍcAMP and H-NS. Results revealed that $P1_S$ was the responsible promoter activated under a high osmolarity and low pH. The P2 promoter was identified 45 nucleotides downstream from $P1_E$ and negatively controlled by CRPㆍcAMP in vitro. No P2 activity was detected in vivo. The regulation of stn expression monitored using a Pstn::egfp fusion indicated that $E{\sigma}^S$ was required for the induction of stn and various factors were involved in stn regulation inside animal cells.