• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.291-294
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• 2006

Clostridium perfringens strains were isolated from swine diarrhea in Korea. Three out of nineteen (15.8%) isolates of C. perfringens were found to be enterotoxigenic by PCR analysis. PCR-based genotyping of the three enterotoxigenic isolates of C. perfringens revealed that they were types A, C and D, respectively. These results suggest that various types of enterotoxigenic C. perfringens can cause swine diarrhea, and that the presence of enterotoxigenic type A strain, known to be strongly associated with food poisoning, may cause public health problem in Korea.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.161-167
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• 2015

These commensal intestinal bacteria can enhance the immune system and aid in nutrient absorption but can also act as opportunistic pathogens. Among these intestinal bacteria, the anaerobic Bacteroides fragilis are divided into enterotoxigenic B. fragilis (ETBF) which secrete the B. fragilis toxin (BFT) and non-enterotoxigenic B. fragilis (NTBF) which do not secrete BFT. ETBF can cause diarrhea and colitis in both humans and livestock but can also be found in asymptomatic individuals. ETBF is predominantly found in patients with inflammatory diarrheal diseases and traveller's diarrhea. Several clinical studies have also reported an increased prevalence of ETBF in human patients with inflammatory bowel disease (IBD), colitis and colorectal cancer. In small animal models (C57BL/6 wild-type mice, germ-free mice, multiple intestinal neoplasia (Min) mice, rabbits and Mongolian gerbils), ETBF have been found to initiate and/or aggravate IBD, colitis and colorectal cancer. BFT induces E-cadherin cleavage in intestinal epithelial cells resulting in loss of epithelial cell integrity. Subsequent activation of the ${\beta}$-catenin pathway leads to increased cellular proliferation. In addition, ETBF causes acute and chronic colitis in wild-type mice as well as enhances tumorigenesis in Min mice via activation of the Stat3/Th17 pathway. Currently, ETBF can be detected using a BFT toxin bioassay and by PCR. Advances in molecular biological techniques such as real-time PCR have allowed both researchers as well as clinicians to rapidly detect ETBF in clinical samples. The emergence of more sensitive techniques will likely advance molecular insight into the role of ETBF in colitis and cancer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.621-628
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• 1991

Heat-stable enterotoxin(ST) from enterotoxigenic E. coli eKT-53($ST^{+}\;LT^{-}$, transformant from isolate KM-7) that was produced in succinate salts medium. The culture supernatant(crude ST) was purifed by mulitpled steps and investigated some characterization of the ST. The heatstability of purified ST activity was completely lost by treating at $100^{\circ}C$ for 30minutes. ST activity was lost by treatment at pH 1 and 12 conditions, while the activity was not reduced by treatment at pH 2~10, and then the ${\alpha}-amylase$ and pepsin was not decreased activity but disulfide reducing agnets was lost the activity. The molecular weight of the purified ST was approximately 4,200, the isoelectric point was about 4.0.

• Korean Journal of Veterinary Service
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• v.15 no.1
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• pp.26-31
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• 1992

The oil emulsion and alhydrogel vaccines were prepared from a strain of enterotoxigenic Escherichia coli isolated from calves with diarrhea and their protective efficacy and immunogenicity were tested in Guinea-pigs. Enterotoxigenic Escherichia coli, isolated from calves with diarrhea, has K99 and F4l antigen as 46.2％ and 50.9％ with 48 and 53 strains respectively out of 104 strains. The protective efficacy of the gel and oil vaccines were 60% and 80% respectively. Agglutinin titers to sera of Guinea-pigs vaccinated with experimental gel and oil vaccines peaked at 5 and 6 weeks after vaccination.

• Korean Journal of Veterinary Research
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• v.53 no.2
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• pp.83-88
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• 2013

Field efficacy of enterotoxigenic Escherichia coli-specific phage (${\Phi}CJ19$) as a feed additive was evaluated in weaning piglets. Fifty-four piglets at 3-4 weeks old were allocated in three different groups and two of them were fed with bacteriophage at different concentrations ($10^6PFU/kg$ feed and $10^8PFU/kg$ feed, respectively) for 30 days. Body weight and feed intake were measured at 10 days interval and body condition and fecal score were inspected every day. Based on the measurement, feed conversion rate (FCR) and average daily gain (ADG) of each group during 30 days were analyzed. The analysis suggests that the bacteriophage may help the improvement of FCR and ADG at $10^8PFU/kg$ of bacteriophage feeding group in 30 days. A result from analysis of fecal score indicates that the bacteriophage also may help to relieve the intermittent diarrhea in post-weaning stage. Those results suggest that bacteriophage might help the growth of piglets in post-weaning stage.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1552-1558
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• 2021

The diverse microbial communities in kimchi are dependent on fermentation period and temperature. Here, we investigated the effect of enterotoxigenic Escherichia coli (ETEC) during the fermentation of kimchi at two temperatures using high-throughput sequencing. There were no differences in pH between the control group, samples not inoculated with ETEC, and the ETEC group, samples inoculated with ETEC MFDS 1009477. The pH of the two groups, which were fermented at 10 and 25℃, decreased rapidly at the beginning of fermentation and then reached pH 3.96 and pH 3.62. In both groups, the genera Lactobacillus, Leuconostoc, and Weissella were predominant. Our result suggests that microbial communities during kimchi fermentation may be affected by the fermentation parameters, such as temperature and period, and not enterotoxigenic E. coli (ETEC).

• Biomedical Science Letters
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• v.19 no.2
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• pp.142-146
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• 2013

Enterotoxigenic Bacteroides fragilis (ETBF) causes inflammatory diarrhea in humans and animals and is also implicated in colorectal cancer. ETBF-infected mice exhibit a prominent large intestinal inflammation characterized by neutrophil infiltration and induction of the Th17 response. In this study, we examined differences in the secreted cytokine profile of the cecum and proximal colon of ETBF-infected mice using an antibody array. Of the cytokines examined, we found that the cecal tissues from ETBF-infected mice secreted elevated levels of G-CSF, IL-6, IL-17 and LIX compared to non-toxigenic Bacteroides fragilis (NTBF) and Mock infected mice. The proximal colon tissues from ETBF-infected mice secreted higher levels of G-CSF, IL-6, KC, LIX, MIP-1g and MCP-1. This study demonstrates that the cecum and colon should be considered separately when assays are used to determine immune responsiveness to enteric infections.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.9-15
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• 2017

To construct a novel vaccine candidate against bovine enterotoxigenic Escherichia coli (ETEC), FanC, the major subunit of K99 fimbriae adhesion, was inserted into secretion plasmid pYA3560 containing a ${\beta}-lactamase$ secretion system. This was then transformed into ${\Delta}asd$ ${\Delta}crp$ Salmonella (S.) Typhimurium and designated as JOL950. Secretion of recombinant fanC fimbrial antigens was confirmed by immunoblot analysis. Groups of mice were inoculated with single or double doses of JOL950. Another group was used as a negative control. Compared to control mice, all immunized mice had significantly higher levels (p < 0.05) of serum immunoglobulin (Ig)G, and secretory IgA against FanC. The IgG2a and IgG1 titer assays revealed that immunization highly induced IgG2a compared to that of IgG1, indicating that T helper-1- related cell-mediated immune responses may be elicited by JOL950. The results show that both systemic and mucosal immunities against selected fimbrial antigens of bovine ETEC expressed by a live attenuated S. Typhimurium strain are prominently produced in mice immunized with JOL950 via an oral route.

• Biomedical Science Letters
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• v.24 no.3
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• pp.275-279
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• 2018

Inflammatory bowel disease (IBD) is increasing in prevalence in developed countries but the cause of this increase is unclear. In animal models of IBD and in human IBD patients, alterations in the tight junctional proteins have been observed, suggesting that the intestinal microflora may penetrate the underlying colonic tissue and promote inflammation. Enterotoxigenic Bacteroides fragilis (ETBF) causes inflammatory diarrhea in human and is implicated in inflammatory bowel diseases. However, it is unclear whether alterations in tight junctional proteins occur during ETBF infection in mice. In this brief communication, we report that ETBF infection induces up-regulation of claudin-2 and down-regulation of claudin-5 through B. fragilis toxin (BFT) activity in the large intestine of C57BL/6 mice. In contrast, BFT did not induce changes in tight junctional proteins in the HT29/C1 cell line, suggesting that analysis of biological activity of BFT in vivo is important for evaluating ETBF effects.

• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.131-137
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• 1987

The incidnce of enterotoxigenic Esherichia coli(ETEC) was investigated in E. coli strains isolated from Korean infants less than two years old. Over a period of 12 months, ETEC strains have been isolated from 45(45.0%) of 100 children with acute diarrhea and from 9(20.5%) of 44 children without diarrhea. In the group with diarrhea, 41(41.0%) strains produced heat-stable toxin, 3(3.1%) produced heat-labile toxin, and 1(1.0%) produced both heat-stable and heat-labile toxins. In the control group, 7(15.9%) released heat-stable toxin, 2(4.5%) released heat-labile toxin and none released both. A statistical association of strains releasing heat-stable toxin was significant(P<0.025).