• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.49-59
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• 1986

This paper deals with the distribution, reservoir and mode of spread of salmonella infection on 7 pig farms in Taegu, Gyeongbuk, Gyeongnam and Chungnam and a slaughter house in Teagu during the period from May 1984 to May 1985. Isolated salmonella were examined for serotypes and biotyping of S. typhimurium. The results obtained were summarised as follows; 1. Of total 7,995 samples from 7 pig farms and a slaughter house, 319 salmonella were isolated from 234 samples (2.9%) and their serovar strains were S. derby 77, S. infantis 41, S. enteritidis 20, S. typhimurium 18, S. bredeney 16, S. london 14, S. paratyphi B 9, S. anatum 8, S. montevideo 8, S. senftenberg 7, S. thompson 6, S. pullorum 4, S. paratyphi A 1 and untypable 70. 2. The incidence rate of diarrhea of piglets, weaned pigs and fattening pigs was 9.8%, 2.3% and 0.5%, respectively whereas the rate by salmonella infection was 4.2%, 1.2% and 11.3%, respectively. 3. The isolation rate of salmonella was higher in summer and autumn. 4. The isolation rate of salmonella varied from 1.1% to 4.5% in 7 pig farms, it was higher in sewages(4.4%), weaned pigs(3.7%), boars(3.7%) and other(3.7%) included soils, manure and wild rats according to samples. Three out of 7 pig farms were contaminated heavily with various serovars of salmonella. 5. The isolation rate of salmonella from pigs slaughtered was 8.1%, it was 13.6% in rectal contents and 1.6% in mensenteric lymph nodes. 6. Eighteen strains of S. typhimurium were classified into 3 different biovars(1, 10 and 10a) by the method of Brandis and were subdivided into 6 different full biovars(1a, 1d, 1dh, 3d, 26i and 26ei) by the method described by Duguid et al. Appearance of different biovars indicated the occurrence of different exotic infection sources on the farms.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.181-189
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• 1986

To apply ELISA to serodiagnosis of leptospirosis with killed whole cells from Leptospira interrogans serovars mwogolo (Mwogolo), copenhageni (M-20), WH-20, autumnalis (Akiyami A), cynopteri (3522 C), australis (Bacillico) and Leptospira biflexa serovar patoc (patoc 1), sensitivity and specificity was evaluated. The reactivity of IgM and IgG antibody in the sera from patients with leptospirosis, hemorrhagic fever with renal syndrome and other febrile disease and normal healthy control to the killed whole cells was analysed. The results were summarized as follows. 1. The reactivity (absorbance at 492mn) of IgM and IgG to L. mwogolo antigen in the sera of pattients with leptospirosis were $1.414{\pm}0.370$, $1.242{\pm}9.554$ respectively: hemorrhagic fever with renal syndrome, $0.329{\pm}0.131$, $0.239{\pm}0.126$; other febrile disease, $0.196{\pm}0.071$, $0355{\pm}0.141$; normal healthy control, $0.136{\pm}0.016$, $0.208{\pm}0.077$. 2. The reactivity of IgM and IgG to L. copenhageni, WH-20, L. autumnalis, L. cynopteri and L. anstralis antigens were similar to that to L. mwogolo antigen, but that to L. biflexa antigen was not discriminated among above disease. 3. Correlation coefficient between the MAT titer and ELISA OD (IgM) to the above antigens was in the range of 0.071-0.518. 4. As absorbance above 0.60 was determined positive for the diagnosis of leptospirosis, the sensitivity and specificity of IgG was 25-89% and 91-96% respectively. And those of IgM was 98-100% and 89-100% except L. biflexa (29%) respectively.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.47-53
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• 2011

Salmonella enterica serovar Typhimurium (ST) is one of the most common serovars isolated from humans and animals. It has been suggested that ST infections in Koreans are largely due to the consumption of contaminated pork and beef. To investigate the genotypes, phage types, and antimicrobial resistance patterns for ST isolates of different origins, a total of 70 ST strains, including 19 isolates from humans, 44 isolates from pigs, and 6 isolates from cattle, were analyzed using pulsedfield gel electrophoresis (PFGE), phage typing, and antimicrobial susceptibility tests. Forty-three distinct PFGE patterns were generated from 70 ST isolates, which were grouped into 14 PFGE groups (from A to N) at the level of 75% similarity. The most prevalent group was the A (A1-A17 subtypes) group, encompassing 54.5% (38/70) of ST isolates. ST isolates from pigs and cattle mostly belong to groups A and L, whereas ST isolates from humans mostly belong to groups F and C. Antimicrobial susceptibility tests using 11 antimicrobial agents showed that resistance to tetracycline (TE) (81.4%) was highly prevalent, followed by streptomycin (S) (64.3%) and nalidixic acid (NA) (31.4%) resistance. A total of seventeen antimicrobial resistance patterns were observed. Only 8.6% of isolates, including a reference strain, were susceptible to all antimicrobial agents tested. The most prevalent resistance pattern was TE-S (37.1%), which was seen in 66.6% of bovine, 40.8% of swine and 21.1% of human isolates. Three ST isolates from humans (15.9%) showed resistance to 7-8 antimicrobials. The most predominant phage type (PT) was U302 (64.3%), followed by DT170 (10.0%). PFGE types did not coincide with antimicrobial resistance patterns and phage types; therefore, the combination of those types allowed for further differentiation between tested ST isolates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.1-7
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• 2007

Antimutagenic and in vitro anticancer effects of doenjangs added with green tea extract and/or using bamboo salt were studied by Ames test using Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) TA100 and 3-(4,5-dimethylthiazol) -2,5-diphenyltetrazolium bromide (MTT) assay on PC-3 and DU145 human prostate cancer cells, respectively. At the 1.25 mg/plate concentration, 1% green tea extract (GTE) added doenjang exhibited 85% antimutagenicity against aflatoxin $B_1$ ($AFB_1$), while the control doenjang revealed 63% antimutagenicity, showing increased antimutagenic effect by the addition of green tea extract during doenjang fermentation. GTE added doenjang also increased antimutagenic effect against MNNG. The inhibition rate of the control doenjang showed 34% at 0.625 mg/plate, while 1% and 2% GTE added doenjangs inhibited by 56% and 73% at the 0.625 and 1.25 mg/plate, respectively (p<0.05). In MTT assay, GTE added doenjangs caused 70% $\sim$ 77% inhibition on the proliferation of PC-3 human prostate cancer cells at 0.5 mg/mL while the control doenjang exhibited 46% inhibition. However, 2% GTE added doenjang showed 91% inhibition at 1.0 mg/mL. The trend of the inhibition rate was similar in DU14S human prostate adenocarcinoma cells. When bamboo salt was used instead of natural sea salt, the antimutagenicity against MNNG and in vitro anticancer effect on the prostate cancer cells greatly increased. From these results, it can be concluded that green tea extract addition to doenjang and the use of bamboo salt during doengjang preparation increased the antimutagenic and in vitro anticancer activities of the doenjang and showed a synergistic effect.

• Food Engineering Progress
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• v.21 no.1
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• pp.88-92
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• 2017

We attempted to investigate antibacterial and proteolytic activities of bacteria isolated from three ethnic fermented seafoods in the east coast of South Korea, gajami sikhae, squid jeotgal, and fermented jinuari (Grateloupia filicina). Bacillus cereus ATCC 14579, Listeria monocytogenes ATCC 15313, Staphylococcus aureus KCTC 1916, Escherichia coli O157:H7 ATCC 43895, and Salmonella enterica serovar Typhimurium ATCC 4931 were selected to determine the antibacterial activity of the bacterial isolates. Among 233 isolates from the three foods, 36 isolates (15.5%) showed antibacterial activity against B. cereus ATCC 14579, the highest incidence of inhibition, followed by S. aureus KCTC 1916 (7.7%) and L. monocytogenes ATCC 15313 (6.0%). However, only five and three strains among the isolates exhibited inhibitory activity against Gram-negative indicators, E. coli ATCC 43895 and Sal. enterica ATCC 4931, respectively. The proteolytic activity of the isolates was determined via hydrolysis of skim milk after 24, 48, and 72 h incubation. After 72 h incubation, 72 out of 233 isolates (30.9%) showed proteolytic activity, and the isolates of fermented jinuari exhibited the highest incidence of proteolytic activity (60%, 36 isolates). These results suggest that ethnic fermented seafoods in the east coast of South Korea might be a promising source of bacterial strains producing antibacterial and proteolytic compounds.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.83-95
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• 2023

These days, bacterial detection methods have some limitations in sensitivity, specificity, and multiple detection. To overcome these, novel detection and identification method is necessary to be developed. Recently, NGS panel method has been suggested to screen, detect, and even identify specific foodborne pathogens in one reaction. In this study, new NGS panel primer sets were developed to target 13 specific virulence factor genes from five types of pathogenic Escherichia coli, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium, respectively. Evaluation of the primer sets using singleplex PCR, crosscheck PCR and multiplex PCR revealed high specificity and selectivity without interference of primers or genomic DNAs. Subsequent NGS panel analysis with six artificially contaminated food samples using those primer sets showed that all target genes were multi-detected in one reaction at 10⁸-10⁵ CFU of target strains. However, a few false-positive results were shown at 10⁶-10⁵ CFU. To validate this NGS panel analysis, three sets of qPCR analyses were independently performed with the same contaminated food samples, showing the similar specificity and selectivity for detection and identification. While this NGS panel still has some issues for detection and identification of specific foodborne pathogens, it has much more advantages, especially multiple detection and identification in one reaction, and it could be improved by further optimized NGS panel primer sets and even by application of a new real-time NGS sequencing technology. Therefore, this study suggests the efficiency and usability of NGS panel for rapid determination of origin strain in various foodborne outbreaks in one reaction.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.156-162
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• 2008

Salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, self-limited enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Recently, the emergence of multidrug resistant strains of Salmonella spp. causes more serious problems in environment and public health. The present study was investigated the antibacterial effect of Houttuynia cordata ethanol extract(HCEE) for murine salmonellosis. In the cytotoxic effect of HCEE on RAW 264.7 cells, there was no detectable effect with any concentrations between 25 and 100 ${\mu}g/ml$ after 8 h incubation. The bacteriocidal effect of HCEE was not showed on a Salmonella enterica serovar Typhimurium(S. typhimurium). HCEE makes morphological change of the RAW 264.7 cells, and there was significant decreased bacterial uptake and intracellular replication within Salmonella infected cells. And further nitric oxide(NO) production of Salmonella infected RAW 264.7 cells with HCEE was decreased comparing to RAW 264.7 cells without HCEE until 8 h post infection. Oral administration of HCEE showed a therapeutic effect for S. typhimurium infected BALB/c mice. The mortality of HCEE treated mouse was 80% until 12 days, while that of HCEE untreated mouse was 100 % until 8 days after lethal dose of S. typhimurium infection. These data suggested that HCEE has a potency treatment for intracellular replicative pathogen including salmonellosis, brucellosis, tuberculosis, listeriosis etc., and the application of HCEE makes new strategies for safety medicine development without antibiotic resistance bacterial appearance and residue problem in food and solves the public health problem from antibiotic mis- and over use.

• Journal of environmental and Sanitary engineering
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• v.3 no.2 s.5
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• pp.23-41
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• 1988

Two hundred and eighty-six strains of Salmonella species were isolated from the twelve provincial institutes of health and 19 general hospitals of urban and rural areas in Korea from January to December in 1986. The antimicrobial susceptibility test of these cultures was done by the method of agar diluton. The resistance frequency of Salmonella cultures was $29.7\%$. Among these resistant cultures, the most provalent resistance pattern of Salmonella was ampicillin, carbenicillin, chloramphenicol, tetracycline, streptomycin, and its resistance frequency was $15\%$. In plasmid profile of resistance strains, average number of plasmid harboring in Salmonella was 1-4 and molecular weight of plasmid ranged 1.6 to 70 megadalton (Md.). Plasmid pattern of strains isolated from Seoul and Kang-won showed the same or similar profiles. Plasmid pattern was identical in the same resistance pattern.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.7-13
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• 2015

Hydrotrope-combined copper (HCC) is a copper ($Cu^{2+}$)-based algicide, which is combined with a hydrotrope that keeps copper ion in solution to improve performance. This study assessed the growth inhibition effect of HCC against Microcystis aeruginosa which is one of the most common toxic cyanobacterium in eutrophic freshwater environment. Various HCC doses, ranging from 5.5 to $550{\mu}g/L$ as $Cu^{2+}$, were applied to either BG-11 or 1/4 diluted medium with low- or high-inoculum density of M. aeruginosa. Growth inhibition was monitored based on a decrease in chlorophyll-a content in culture medium during the incubation. Results showed that HCC significantly inhibited the growth of M. aeruginosa in a dose-dependent manner. In case of 1/4 diluted BG-11 medium, HCC dose as low as $5.5{\mu}g$ $Cu^{2+}/L$ completely inhibited the production of chlorophyll-a by M. aeruginosa. It was found that HCC did not induce any significant release of microcystin-LR from M. aeruginosa. Acute toxicity of HCC was tested using Daphnia magna, and the 24-h $EC_{50}$ value was 0.30 mg/L as $Cu^{2+}$ which was much higher than the actual inhibition dose. Ames test was performed using Salmonella enterica serovar Typhimurium TA100, and HCC showed no increase in the number of revertant colonies. The result suggested that HCC does not have any mutagenic potential in the aquatic environment. In addition, no genotoxic effect of HCC was also confirmed based on the SOS ChromoTest using Escherichia coli PQ37. Therefore, HCC could be used as a relatively safe and effective pre- and post-treatment agent to control hazardous algal blooming in aquatic environments.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.111-119
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• 2010

Salmonella spp. are one of major pathogens for zoonosis in worldwide, and can replicate within host cells and generally cause enterocolitis and foodborne poisoning which represents a considerable public health burden. The present study was designated to investigate the safty for host cells, antibacterial effects of Saururus chinensis Baill water extract (SCWE) on pure culture and infection with Salmonella enterica serovar Typhimurium (S. typhimurium) in murine derived macrophage RAW 264.7 cells. The different treatment of SCWE concentration (1, 10 or $100{\mu}g/ml$) did not show any cytotoxic effect to RAW 264.7 cells for 24 h incubation. In determination of antibacterial activity of SCWE against S. typhimurium, bacterial viability was markedly decreased compared to SCWE-untreated control. In RAW 264.7 cells, SCWE significantly induced morphological change (p<0.05). In infection assay of S. typhimurium in RAW 264.7 cells pretreated with $100{\mu}g/ml$ of SCWE, which are non-cytotoxic concentration, bacterial uptake ability of macrophage was increased corresponding with morphological change, whereas bacterial survival rates within macrophage was markedly reduced comparing to that of SCWE-untreated control. Furthermore, nitric oxide (NO) production in SCWE-treated cells was slightly decreased until 24 h post infection. Taken together, these findings demonstrated that SCWE have the antibacterial activity for S. typhimurium and the protective effects against S. typhimurium infection through activating murine macrophage independent on NO, suggesting that SCWE were beneficial on the disease caused by intracellularly replicating pathogens as a safe alternatives of conventional chemotherapies.