• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.53-62
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• 1991

Experiments were performed in mice(Balb/C) to support the basic efficacy of the human immunoglobulin (IgG) preparation. The antibacterial activity of IgG purified from human sera was examined with or without the quinolone agent, ciprofloxacin(CPFX), against Pseudomonas aeruginosa isolated from clinical specimens. Results were as follows: Antibacterial activities in terms of the percentage of survivors, after administration of Ps. aeruginosa into mouse intraperitoneal cavity were in the following order, single IgG group, CPFX administration after IgG pretreatment group, IgG and CPFX combined administration group and CPFX alone group. The number of living bacteria was monitored in blood and liver tissue of mice infected with Ps. aeriginosa and treated by IgG administration. The increase of living bacteria in liver was more drastic than that in blood. Leukocytosis was observed in mice injected with IgG, excluding those only with ciprofloxacin, after 8 hours of administration to see a decrease to normal number of bacteria after 18 hours. No significant difference was noticed between pretreatment group and post treatment group. In vitro susceptibility test of IgG against Ps. aeruginosa, minimal inhibitory concentration(MIC) was $250{\mu}g/ml$, resistant to IgG, regardless of a combined administration with CPFX. In vitro test revealed that the IgG itself did not have anti-Ps. aeruginosa activity.

• Journal of Life Science
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• v.13 no.4
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• pp.421-427
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• 2003

A natural habit at bacterium, Enterobacter intermedious KH410 was isolated from freshwater plant root and identified. Adsorption of heavy metals such as lead, cadmium, and copper by this strain was examined. The minimal inhibitory concentrations(MIC) for each metal were 1.78 mM for lead, 0.17 mM for cadmium and 1.39 mM for lopper, respectively. Maximum production of dried cell was 2.56 g/$\ell$ in LB medium containing 0.5% NaCl, 1% yeast extract and 1% of lactose. Optimal conditions for adsorption were 0.6 dry g-biomass, at pH 4.0 and the temperature of $20^{\circ}C$. Adsorption equilibrium reached maximum after 30 min in 400 mg/$\ell$ metal solution. The adsorption capacity (K) of copper was 1.5 times higher than that of cadmium and lead was 1.1 times higher than that of cadmium. from the results obtained in this study, Freundlich adsorption model was applicable for all metals. Adsorption strength (1/n) of heavy metal ions were in the order of cadmium>copper>lead. The adsorption of dried cell for lead, cadmium, and copper was 56.2, 58.0, 55.8 mg/g-biomass, respectively. Pretreatment to increase ion strength was the most effective with 0.1 M NaOH whereas slight difference was found both KOH and $CaCl_2$ upon same concentration. Effective desorption was induced by 0.1 M EDTA for lead and 0.1 M $HNO_2$ for cadmium and copper.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.93-101
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• 2012

We analyzed mupirocin resistance rates among staphylococcal isolates collected from a Korean hospital in 2003 (100 isolates), 2005 (195 isolates), 2006 (151 isolates), and 2009 (112 isolates). In Staphylococcus aureus, rates of high-level mupirocin resistance (MIC, minimal inhibitory concentration ${\geq}512{\mu}g/ml$) decreased and did not appear since 2005. In contrast, low-level mupirocin resistance (MIC $8-256{\mu}g/ml$) was not detected in 2003 and 2005 but its rates later increased to 6.9% in 2009. Total resistance rates of coagulase-negative staphylococci (CNS) were significantly higher than those of S. aureus. The rates of high-level resistance of CNS increased from 16.0% in 2003 to 31.5% in 2009. The rate of low-level resistance of CNS was 8.0% in 2003 and around 11% later. In all high-level resistant isolates, the ileS-2 gene was detected. All low-level resistant isolates contained the known V588F mutation in ileS gene. Previously unknown mutations such as V458G in S. aureus and D172A, Y490H and I750V in CNS were identified additionally. One S. aureus isolate with high-level resistance was resistant to oxacillin and several topical antibiotics commonly used for the treatment of skin infection. Ten S. aureus isolates with low-level resistance were also resistant to all of these antibiotics except fusidic acid. CNS isolates with high-level (61 isolates) and low-level resistance (27 isolates) exhibited significantly higher resistance rates to these antibiotics than mupirocin-susceptible CNS isolates (167 isolates). In conclusion, prevention of the emergence of mupirocin resistance is necessary for the effective treatment of skin infection by staphylococci.

• Journal of Life Science
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• v.25 no.4
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• pp.433-440
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• 2015

Several studies suggest that regular consumption of walnuts may have beneficial effects against oxidative stress-mediated disease such as cancer. The present study reports the total phenolic and flavonoid contents, together with the antioxidant and antibacterial activities of several solvent extracts (methanol, n-hexane, ethyl acetate, n-butanol, and water) obtained from walnut (Juglans regia L.) green husk. MIC (minimal inhibitory concentration) values of the walnut extracts for 8 human pathogenic bacteria strain were determined using agar dilution method. Antioxidant activity of extracts were assessed using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) assays, EC₅₀ of DPPH and ABTS scavenging activities, and determination of total phenolic and flavonoid content and its correlation with DPPH and ABTS scavenging capacities. Among the six extracts, ethyl acetate extract (EtOAc Ex) showed the highest antimicrobial activity at 3.2 mg/ml of MICs against Staphylococcus aureus SG511. Total flavonoids and polyphenol contents of EtOAc Ex were 42.48 mg of quercetin equivalents (QE)/g and 223.25 mg of gallic acid equivalents (GAE)/g respectively. The highest antioxidative potential was shown by the sample extracted with EtOAc Ex (EC₅₀=13.43 μg/ml for DPPH and EC₅₀=41.83 μg/ml for ABTS radical scavenging activity assay). These results showed that J. regia green husk extracts can be used as an easily accessible source of natural antibacterial agents and natural antioxidants.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.382-390
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• 2020

This study was carried out to evaluate the antimicrobial effect of red ginseng (Panax ginseng C.A. Meyer) against several foodborne pathogens including Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger. The antimicrobial effect was determined by agar diffusion method using red ginseng extract, crude saponin and non-water-soluble fractions. Red ginseng extract showed antimicrobial effect against S. aureus, but not C. albicans or A. niger. The extract showed anti-bacterial activity at concentration above 30% against S. aureus, which cause both food poisoning and atophic dermatitis. Crude saponin showed antibacterial activity above 7.5% against the bacterium. However, the ginsenosides purified from crude saponin showed no antimicrobial activities at 100-200 ㎍/mL. To investigate the mode of growth inhibition, red ginseng extract and crude saponin were added to 0.85% NaCl solution containing S. aureus and then incubated at 35℃ for 12 h. The results showed that viable cells were rapidly reduced in above 10% concentration of red ginseng extract and above 2% of crude saponin, respectively. However, the crude saponin and red ginseng extract did not inhibit the bacterial cells completely at those same concentrations. On the other hand, whereas all non-water-soluble fractions showed inhibition zones above 10 mm against S. aureus, they showed no inhibition effects against E. coli, C. albicans or A. niger. The methanol fraction-1 (MF-1) showed the highest antibacterial activity against S. aureus, and the MIC (minimal inhibitory concentration) was 0.625 mg/mL. These results suggest that red ginseng extract, crude saponin and non-water-soluble fractions show selective antibacterial activity against S. aureus, and non-water-soluble fractions might be used as natural antibacterial agents.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.376-382
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• 2014

Various solvents (chloroform, hexane, ethyl acetate, ethanol, methanol, and hot water) were tested to investigate the antimicrobial activities of sword bean (Canavalia gladiata) against 12 food poisoning bacteria. Chloroform, hexane, ethyl acetate and hot water extracts had no antimicrobial activities, but ethanol extract showed V. parahemolyticus 10 mm, S. sonnei 9 mm, and methanol extract showed strong activities in order of V. parahemolyticus 22 mm, S. sonnei 21 mm, L. monocytogenes 20 mm by disk diffusion. The minimal inhibitory concentrations (MICs) were also determined. The methanol extract had MIC values of 50 mg/mL against S. Typhimurium, V. parahemolyticus, and S. sonnei and values of 100 mg/mL against other 7 food poisoning bacteria and values of 200 mg/mL against Y. enterocolitica and MRSA. The inhibitory effect of methanol sword bean extract on the growth of V. parahemolyticus was investigated. Growth of the strain occurred at the concentration of 0.5% extract and was inhibited continuously at 1.0 and 1.5% for 30hours after inoculation, whereas the strain was completely inhibited at 2.0% after 9hours of inoculation.

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.75-79
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• 2010

A total of 25 isolates of Fusarium fujikuroi were obtained from diseased rice plants in Korea from 2006 to 2007 to assess their resistance against fungicides prochloraz and benomyl + thiram. Minimal inhibitory concentration (MIC) values of F. fujikuroi isolates were examined by agar dilution method. Most of the isolates were sensitive to the fungicides. Out of 25 isolates, six were resistant to prochloraz and three to benomyl + thiram. In addition, the isolates CF245, CF249 and CF337 showed resistant to both fungicides. The progenies ($F_1$ isolates) obtained through two different crosses between sensitive parental isolates(CF202, CF232 and CF179) and resistant parental isolate (CF337) were evaluated for their mycelial growth at different temperatures and resistance against fungicides. Mycelial growth rate of $F_1$ isolates originated from CF202 $\times$ CF232 was similar to the parental isolates. However mycelial growth rate of $F_1$ isolates originated from CF179 $\times$ CF337 was faster than their parent isolates. In case of prochloraz, distribution ratio of sensitivity(S) to resistance(R) against to the fungicide of $F_1$ isolates originated from CF202 $\times$ CF232 and CF179 $\times$ CF337 was 86 : 14 and 78 : 22, respectively. In case of benomyl+thiram, all the $F_1$ isolates originated from CF202 $\times$ CF232 were sensitive to the fungicide, however ratio of sensitivity(S) to resistance(R) against to the fungicide of $F_1$ isolates originated from CF179 $\times$ CF337 was 35 : 65.