• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.280-285
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• 1995

To develop natural food preservatives, antimicrobial effect of the ethanol extract of leaf mustard against E. coli and S. aureus were examined in terms of compositions and leakage of cellular materials in the microorganisms treated with the extract. No effect of the concentration of ethanol extract on the fatty acid composition of E. coli and S. aureus at logarithmic phase was showen, but the content of palmitic and palmitoleic acid of E. coli slightly increased and decreased, respectively, and the content of palmitic and margaric acid of S. aureus slightly increased, when compared to each control. Ethanol extract did not affect most of the amino acids E. coli and S. aureus at logarithmic phase ; however, some of them(proline, glycine, valine and histidine of E. coli and proline, methionine and histidine of s. aureus) were elevated and some other amino acid(aspartic acid, glutamic acid, tyrosine and arginine of E. coli and aspartic acid, glutamic acid, glycine, alanine and lysine of Staph. aureus) found to be decreased. The amount of cell body protein leaked from E. coli and S. aureus increased to 1.02 and 0.22mg/g cell weight, respectively, as compared to controls. Similarly, the substances with absorbance at 260 nm from E. coli and s. aureus increased to 0.12 and 0.06mg/g cell weight, respectively.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1350-1357
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• 2021

Staphylococcus aureus (S. aureus) is a major pathogen that causes human pneumonia, leading to significant morbidity and mortality. S. aureus coagulase (Coa) triggers the polymerization of fibrin by activating host prothrombin, which then converts fibrinogen to fibrin and contributes to S. aureus pathogenesis and persistent infection. In our research, we demonstrate that isovitexin, an active traditional Chinese medicine component, can inhibit the coagulase activity of Coa but does not interfere with the growth of S. aureus. Furthermore, we show through thermal shift and fluorescence quenching assays that isovitexin directly binds to Coa. Dynamic simulation and structure-activity relationship analyses suggest that V191 and P268 are key amino acid residues responsible for the binding of isovitexin to Coa. Taken together, these data indicate that isovitexin is a direct Coa inhibitor and a promising candidate for drug development against S. aureus infection.

• Korean Journal of Veterinary Service
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• v.23 no.2
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• pp.153-163
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• 2000

This study was carried out the antimicrobial resistance of staphylococcus aureus isolated from bovine mastitic milk, chickens, korean native cattle, korean native goats, pigs, dog and mice in northern area of kyongbuk. The result were summarised as follows ; A total of 149 S aureus were isolated from bovine mastitic milk, chickens, korean native cattle, korean native goats, pigs, dog and mice. In 80 isolates of S aureus from bovine mastitic milk, 60% of isolates revealed resistance to penicillin and ampicillin, 19% to gentamicin, 6% to tetracycline. In 36 isolates of S aureus from chickens, 72% of isolates revealed resistance to tetracycline, 58% to penicillin and ampicillin, 42% to streptomycin, 31% to lincomycin, 25% to norfloxacin, 22% to gentamicin. In 17 isolates of S aureus from korean native cattle, 100% of isolates revealed resistance to penicillin and ampicillin, 88% to lincomycin, 76% to tetracycline. 2 MRSA were isolated from the isolates of S aureus from bovine mastitic milk and revealed multi-drug resistance.

• Food Science and Preservation
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• v.5 no.1
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• pp.89-96
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• 1998

The antibacterial activity of clove (Eugenia caryophyllata Thumb) in culture troth against S. aureus was tested at 35, 5, -20, 50, 55 and 60$^{\circ}C$. Tryptic soy broth(TSB) containing 0∼0.5%(w/v) of clove was inoculated with 105∼107 CFU/ml of S. aureus and incubated at each temperature. The growth of S. aureus occured at 0.1% clove after a prolonged lag period while viable cells of S. aureus decreased more than 2 log cycles at 0.3 and 0.4% clove during 12 hours storage at 35$^{\circ}C$. During 32 days of refrigerated storage at 5$^{\circ}C$, survivors of S. aureus were decreased with the progress of time and increasing clove concentration. At the presence of 0.2, 0.3 and 0.4% clove, bacterial cells were dead after 32, 20 and 16 days of refrigerated storage, respectively. During 32 days of frozen storage at -20$^{\circ}C$, survivors of S. aureus were decreased less than 0.5 log cycle at 0% clove. At the presence of 0.1∼0.4% clove, survivors were decreased 2.5∼3.0 log cycles after 1 day and then decreased 0.4∼0.8 log cycles through the frozen storage. There were small changes in populations of S. aureus in TSB between different concentrations of clove during frozen storage. The D-values of S. aureus at clove 0, 0,2, 0.4% were 28.53, 15.14, 8.9 min at 50$^{\circ}C$, 18.43, 10.32, 6.74 min at 55$^{\circ}C$ and 12.78, 9.88, 5.72 min at 60$^{\circ}C$, respectively. The D-values for S. aureus were decreased with the increasing temperature and clove concentration.

• Korean journal of food and cookery science
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• v.13 no.2
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• pp.106-112
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• 1997

The effect of low concentrations of allspice (Pimenta dioica L.) in culture broth as an antibacterial agent against Escherichia coli 0157:H7 and Staphylococcus aureus 196E was tested at 35,5 and -20$^{\circ}C$. Tryptic soy broth (TSB) containing 0∼2% (w/v) of allspice was inoculated with 10$\^$5/∼10$\^$6/ cells/$m\ell$ of E. coli and S. aureus and incubated at each temperature. The growth of E. coli was not inhibited at 0.1∼1.0% allspice and growth occured at 2％ allspice but only after a prolonged lag period. Growth of S. aureus was inhibited with increasing concentration of allspice at 35$^{\circ}C$. Growth of S. aureus occured at the presence of 0.1∼0.3% allspice but the viability of S. aureus at 0.5∼2.0% allspice was decreased during storage at 35$^{\circ}C$. During refrigerated storage at 5$^{\circ}C$, inhibition of E. coli and S. aureus was increased with the progress of time and increasing spice concentration. During frozen storage at -20$^{\circ}C$, antibacterial activity of allspice against E. coli was increased with increasing storage time and spice concentration while that activity against S. aureus was effective during early period of storage. There was no major changes in population of S. aureus in TSB with different concentration of spice frozen at -20$^{\circ}C$. Viable counts of E. coli and S. aureus at 0.l％ of allspice was less than that of control during frozen storage.

• Biomedical Science Letters
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• v.13 no.3
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• pp.189-195
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• 2007

This study was carried out to examine antimicrobial substances from medicinal plants, the ethanol extracts of 38 medicinal plants were tested for the antimicrobial activity against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus ATCC 43300. The extracts of Glycyrrhiza uralensis, Sophora flavescens, Dryopteris crassirhizoma, and Pinas densiflora showed significant antimicrobial activities against both S. aureus ATCC 25923 and methicillin-resistant S. aureus ATCC 43300. The extract of Dryopteris crassirhizoma among these medical plants showed the highest antimicrobial activity. These results suggested that the extracts from Dryopteris crassirhizoma, Sophora flavescens, Pinas densiflora, and Glycyrrhiza uralensis could be the potential source of antimicrobial agents against methicillin-resistant S. aureus and S. aureus.

• Food Science of Animal Resources
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• v.39 no.6
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• pp.1015-1020
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• 2019

Staphylococcus aureus is a representative pathogenic bacterium carefully controlled in the dairy industry because it causes bovine mastitis and thus, can enter the dairy chain. Furthermore, the emergence of multi-drug resistant S. aureus is a big problem. We previously isolated a Lactococcus lactis strain producing a bacteriocin that exhibited strong antimicrobial activity against S. aureus. In this study, we investigated the synergistic inhibition of S. aureus by the bacteriocin and a bacteriophage (SAP84) which is specific to the organism. The bacteriocin (12.5-100 AU/mL) inhibited the growth of S. aureus KCTC 3881 in a dose-dependent manner, as did the bacteriophage SAP84 (0.001-1 MOI; multiplicity of infection). Co-treatment with the bacteriocin (100 AU/mL) and the bacteriophage (0.1 MOI) significantly inhibited the growth of S. aureus compared to each treatment alone (bacteriocin or bacteriophage), indicating the two components showed synergistic inhibition of S. aureus. Therefore, the bacteriocin and bacteriophage combination can be used as a good strategy for controlling pathogenic bacteria.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.328-336
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• 2022

Aptamers are short, chemically synthesized, single-stranded DNA or RNA oligonucleotides that fold into unique three-dimensional structures. In this study, we aim to determine the antibiofilm activity and binding specificity of the six polyclonal DNA aptamers (S15K3, S15K4, S15K6, S15K13, S15K15, and S15K20) on Staphylococcus aureus BPA-12 and Escherichia coli EPEC 4. Aptamer S15K6 showed the highest percentage of antibiofilm activity against S. aureus BPA-12 (37.4%) as shown by the lowest OD570 value of 0.313. Aptamer S15K20 showed the highest percentage of antibiofilm activity against E. coli EPEC 4 (15.4%) as shown by the lowest OD570 value of 0.515. Aptamers S15K13 and S15K20 showed antibiofilm activities against both S. aureus BPA-12 and E. coli EPEC4, and thus potentially have broad reactivity. Furthermore, based on the binding capacity and Kd values from our previous study, the binding specificity assay of selected polyclonal DNA aptamers (S15K3 and S15K15) against S. aureus BPA-12, E. coli EPEC 4, S. aureus BPA-6, S. agalactiae, E. coli MHA-6, and Listeria monocytogenes were performed using qPCR. Aptamers S15K3 and S15K15 showed specific binding to S. aureus BPA-12, E. coli EPEC 4, S. aureus BPA-6, and S. agalactiae, but could not bind to E. coli MHA-6 and L. monocytogenes. Therefore, this study showed that the polyclonal DNA aptamers have antibiofilm activity and were able to bind to S. aureus BPA-12 and E. coli EPEC 4 bacteria.

• Biomedical Science Letters
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• v.11 no.4
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• pp.525-531
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• 2005

Staphylococcus aureus is a major cause of nosocomial infections and is one of the most commonly isolated bacterial species in the hospital and continues to be an important pathogen in both community and hospital-acquired infection. Methicillin resistant S. aureus (MRSA), which is associated with hospitals is now being isolated in the community. The purpose of this study is to investigate the carrier rate of S. aureus in the community, antibiotic resistance patterns of the organism, detection of MRSA and mecA gene in MRSA. Ninety strains $(46.4\%)$ of S. aureus were isolated from the nasal specimens of 194 elementary school students. Eighty-nine strains $(98.9\%)$ of 90 S. aureus were resistant to penicilin, 36 strains $(40.0\%)$ to erythromycin, 14 strains $(15.6\%)$ to fusidic acid, 11 strains $(12.2\%)$ to gentamycin, 9 strains $(10.0\%)$ to tobramycin, 5 strains $(5.6\%)$ to oxacillin, 4 strains $(4.4\%)$ to clindamycin, 2 strains $(2.2\%)$ to tetracycline, 1 strains $(1.1\%)$ to fosfomycin. None of $90(0\%)$ S. aureus isolates was resistant to ciprpfloxacin, trimethoprim/sulfamethoxazole, levofloxacin, linezolid, moxifloxacin, nitrofurantoin, norfloxacin, rifampicin, quinupristin/dalfopristin, teicoplanin, and vancomycin. Five strains $(5.6\%)$ of 90 S. aureus isolates were MRSA. The mecA gene was detected from five MRSA strains by PCR.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.846-853
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• 1999

To evaluate clinical effects of autogenous toxoid-bacterin treatment for Staphylococcus aureus subclinical mastitis in lactating cows, 22 cows which had at least one S aureus infected quarter were selected from one S aureus prevalent dairy farm, of which 11 cows were injected their own autogenous toxoid-bacterin and the others were maintain as noninjected control. In the toxoid-bacterin injected group, 27% of infected quarters were cured during the 12 weeks trials as compared to 5% in the control group. New intramammary infections with S aureus were only detected in three-quarters of the control group. Mean IgG antibody titers against S aureus somatic antigens and $\alpha$-toxin in serum and milk were significantly increased in the toxoid-bacterin injected group (p < 0.05) and remained higher than those of the control group which showed no significant changes (p < 0.05). From 3 weeks after second injection (at 7 week), mean S aureus CFU/ml in milk samples from previously infected quarters with S aureus of the toxoid-bacterin injected group was lower than that from preinjection state (p < 0.05). In the toxoid-bacterin injected group, significant decrease of mean SCC was detected from milk samples from previously infected quarters with S aureus from week 7 to week 10 (p < 0.05). These data suggested that autogenous toxoid-bacterin treatment aganist S aureus subclinical mastitis in lactating cows might increase the cure rate of the infections, reduce the severity of the infections and also prevent occurrence of the new infections.