• 약학회지
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• 제42권6호
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• pp.639-641
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• 1998

Minimal inhibitory concentrations (MICs) of Bifidobacterium spp. strains (Bifidobacterium breve K-110, B. breve K-111 and B. infantis K-525) isolated from healthy Korean against antituberculosis agents and fluoroquinolones were determined. From the MICs it was found that Bifidobacterium breve K-110, B. breve K-111 and B. infantis K-525 were susceptible to rifampicin and fluoroquinolenes and resistant to other antituberculosis agents.

• Mycobiology
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• 제36권4호
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• pp.249-254
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• 2008

Minimal growth inhibitory concentrations (MICs) of chitosan acetate (M.W. 60 kDa) on heterotrophic bacteria (strains MK1, S, and R) isolated from the soft-rotten tissues of Neungee mushroom (Sarcodon aspratus) were measured. The slimy substance produced by the MK1 strain was responsible for the diseased mushroom’s appearance. The S and R strains were members of the Burkholderia cepacia complex. These strains showed different levels of susceptibility toward chitosan acetate. The MIC of chitosan acetate against the MK1 and S strains was 0.06%. The MIC against the R strain was greater than 0.10%. Survival fractions of the MK1 and S strains at the MIC were $3\;{\times}\;10^{-4}$ and $1.4\;{\times}\;10^{-3}$ after 24 h, and $2\;{\times}\;10^{-4}$ and $7\;{\times}\;10^{-4}$ after 48 h, respectively. Survival fractions of the R strain after 24 and 48 hr at 0.1% chitosan acetate were $1\;{\times}\;10^{-2}$ and $6.9\;{\times}\;10^{-3}$, respectively. Compared to the MK1 and S strains, the low susceptibility of the R stain towards chitosan acetate could be due to the ability of the R strain to utilize chitosan as a carbon source. Thirty-eight percent of Neungee pieces treated in a 0.06% chitosan acetate solution for $2{\sim}3$ second did not show any bacterial growth at 4 days, whereas bacterial growth around untreated mushroom pieces occurred within 2 days. These data suggest that chitosan acetate is highly effective in controlling growth of indigenous microorganisms on Neungee. The scanning electron micrographs of the MK1 strain treated with chitosan revealed a higher degree of disintegrated and distorted cellular structures.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2129-2140
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• 2017

Silibinin is the major active component of silymarin, extracted from the medicinal plant Silybum marianum. Silibinin has potent antibacterial activity; however, the exact mechanism underlying its activity has not been elucidated. Here, we investigated the novel mechanism of silibinin against Escherichia coli. Time-kill kinetic assay showed that silibinin possess a bactericidal effect at minimal inhibitory concentration (MIC) and higher concentrations (2-and 4-fold MIC). At the membrane, depolarization and increased intracellular $Ca^{2+}$ levels were observed, considered as characteristics of bacterial apoptosis. Additionally, cells treated with MIC and higher concentrations showed apoptotic features like DNA fragmentation, phosphatidylserine exposure, and caspase-like protein expression. Generally, apoptotic death is closely related with ROS generation; however, silibinin did not induce ROS generation but acted as a scavenger of intracellular ROS. These results indicate that silibinin dose-dependently induces bacterial apoptosis-like death, which was affected by ROS depletion, suggesting that silibinin is a potential candidate for controlling bacteria.

• 한국균학회지
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• 제23권2호통권73호
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• pp.153-160
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• 1995

담자균류의 하나인 잔나비걸상 자실체로부터 얻은 수성엑스의 항세균 시험과 항진균 시험을 액체배지 희석법으로 실시하고 naringenin과의 병용시험을 checkerboard assay 법으로 평가하였다. 항세균 시험결과 전반적으로 그람음성균보다 그람양성균에 대해 비교적 양호한 항균력을 나타내었으나 사용된 균주중 그람음성균인 Proteus vulgaris 78615는 MIC가 1.125 mg/ml로 가장 양호한 항균효과를 나타내었다. 11종의 균주에 대해 실시된 항진균 시험결과 Candida albicans, Fusarium spp. 그리고 Trichophyton mentagraphytes의 MIC가 7.5 mg/ml로 다른 균주에 대한 항진균 효과보다 두배 더 강한 효과를 나타내었다. naringenin과의 병용시험에서 Staphylococcus aureus ATCC 25923에 대하여 부분적 상승효과를 나타내었고, Klebsiella pneumoniae ATCC 10031과 Salmonella typhi ATCC 6229 두 균주에서 상가효과가 관찰되었다. 그리고 Bacillus subtilis ATCC 6633을 비롯한 7종의 균주에서 무관효과를 나타내었으며 길항효과는 관찰되지 않았다.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권2호
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• pp.137-142
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• 2007

The antibacterial activity of Korean honey bee venom (KBV) was examined against seven major bacterial mastitis pathogens, Enterococcus faecium, Escherichia coli, Methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus intermedius, Streptococcus oralis and Streptococcus uberis isolated from infected mammary quarters of cows. Seven bacterial mastitis pathogens were studied for antibacterial activity of the KBV by disc diffusion assay, minimal inhibitory concentrations (MIC) and bacterial count in milk samples. The KBV showed activity against Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius. The order of susceptibility of the bacteria against the KBV was Staph. aureus>MRSA>E. coli>Strep. intermedius>Ent. faecium>Strep. oralis>Strep. uberis. The MIC against Staph. aureus, MRSA and E. coli were stronger effect as compared with standard drug. The effect of the KBV ($100{\mu}g\;ml^{-1}$) on the viability of Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius, Strep. oralis and Strep. uberis in milk differed significantly with each other within 12 h incubation period. The results indicate that KBV has significant antibacterial effects against major bacterial mastitis bacteria, Ent. faecium, E.coli, MRSA, Staph. aureus, Strep. intermedius. Results of the study indicate the potential use of KBV as alternative to antibiotic therapy. Further investigations are needed though to confirm its efficacy and its effects on the animals.

• 약학회지
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• 제52권4호
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• pp.274-278
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• 2008

Two known lavandulylated flavanones, leachianone A (1) and sophoroaflavanone G (2), were isolated from the roots of S. flavascens Ait. The structures of these compounds were determined on the basis of IR, 1D and 2D NMR in addition to direct comparison with authentic compounds. However, leachianone A (1) and sophoroflavanone G (2) did not have growth inhibition activity against any microorganisms (MIC, >200 ${\mu}g/ml$).

• Archives of Pharmacal Research
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• 제19권5호
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• pp.400-405
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• 1996

In vitro studies were conducted to dertermine the frequency rate of spontaneous resistance to LB20304 and to dertermine whether cross-resistance to other antimicrobial agents develops. In eight strains of bacteria, the frequency of mutation to LB20304 at the concentrations of four and eight times the minimal inhibitory concentration(MIC) ranaged from less than 4.0 ${\times}$ $10^{-10}$ to 2.2 $\{times}$ $10^{-10}$ . These results were similar to those founf for other new fluoroquinolones. THe development of stepwise resistance was determined by repeated subculture in broth in the presence of increasing concentration of the compounds. Exposure of bacteria to increasing concentrations of LB20304 resulted in the selection of organisms with higher MICs. There were 4- to 128-fold increases in the MIC of LB20304 for bacterial strains of Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli and Pseudomonas aeruginosa. However, those strains selected after repeated exposure were well within the susceptibility range for LB20304 except for Pseudomonas aeruginosa. The resistant isolates selected with LB20304 showed cross-resistance when tested against ciprofloxacin and vice versa.

• 대한한방내과학회지
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• 제34권3호
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• pp.278-288
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• 2013

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) has a cephalosporin and beta-lactam antibiotic-resistant strains. MRSA is one of the major pathogens causing hospital infection and the isolation ratio of MRSA has gradually increased. Consequently, increased resistance to antibiotics is causing serious problems in the world. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. Methods : The antibacterial activities of Ipyo-san were evaluated against 2 strains of MRSA and 1 standard Methicillin-susceptible staphylococcus aureus (MSSA) strain by using the disc diffusion method, minimal inhibitory concentrations (MIC) assay, colorimetric assay using MTT test, checkerboard dilution test and time-kill assay performed under dark. Results : The MIC of Ipyo-san water extract against S. aureus strains ranged from 1000 to $2,000{\mu}g/ml$, so we confirmed that it had a strong antibacterial effect. Also, the combinations of Ipyo-san water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Ipyo-san water extract against MRSA has antibacterial activity so it has potential as alternatives to antibiotic agents. For the combination test, we used Triton X-100 (TX) and DCCD for measurement of membrane permeability and inhibitor of ATPase. As a result, antimicrobial activity of Ipyo-san water extract was affected by the cell membrane. Conclusions : We suggest that the Ipyo-san water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• Food Science and Biotechnology
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• 제15권4호
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• pp.511-515
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• 2006

Antibiotic resistance of foodborne pathogens adapted to garlic (Allium sativum Linn.) was determined in order to understand the relationship between antibiotic resistance and garlic. The Gram (-) strains of Escherichia coli and Salmonella typhimurium and the Gram (+) strains of Bacillus cereus and Staphylococcus aureus were subcultured consecutively in a garlic broth, and the surviving colonies on the agar were selected as the adapted strains. Minimal inhibitory concentrations (MIC) for 15 antibiotics on the adapted strains were determined on Muller-Hinton Infusion agar. Adaptation to 1.3%(v/v) garlic juice increased MIC for vancomycin, aminoglycoside, and erythromycin on B. cereus, and for ampicillin and erythromycin on E. coli O157:H7. MIC of aminoglycosides, chloramphenicol, and vancomycin on the adapted S. aureus increased. The adapted S. typhimurium was more resistant to penicillin and vancomycin than the non-treated strain. The adapted S. typhimurium and S. aureus lost their antibiotic resistance in non-garlic stress conditions. However, the adapted B. cereus was still resistant to erythromycin and vancomycin, and the adapted E. coli was also resistant to erythromycin. Antibacterial garlic might increase the antibiotic resistance of E. coli, B. cereus, S. aureus, and S. typhimurium and this resistance can continue even without the stress of garlic. Therefore, garlic as a food seasoning could influence the resistance of such pathogens to these antibiotics temporarily or permanently.

• 한국식품위생안전성학회지
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• 제24권3호
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• pp.273-276
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• 2009

본 연구는 당 함량이 높고 ($12{\pm}0.1%$) pH가 낮아($3.0{\pm}0.1$) 세균보다는 효모에 의한 변패가 문제시 되고 있은 가능성 음료의 저장성을 향상시키고자 주요 천연항균제 8종의 항균력을 평가하였다. 이에 따라 대표적인 효모균주 Saccharomyces cerevisiae, Zygosaccharomyces bailii, Pichia membranaefciens, Candida albicans, Pichia anomala 5종을 대상으로 $\varepsilon$-Polylysine, 유카추출물, vitamin $B_1$ derivative, scutellaria baicalensis extract, 키토올리고당, allyl Isothiocyanate, 자당지방산에스테르, 올리고당 등 8가지 주요 항균력을 test 하여 최소저해농도 (Minimal Inhibitory Concerntration, MIC)로 나타내었다. S. cerevisiae와 Z. bailii는 올리고당 용액 10 ppm, 자당지방산에스테르 10 ppm, P. membranaefaciens와 C. albicans는 allyl isothiocyanate 10 ppm, P. anomala는 Allyl isothiocyanate 10 ppm, 올리고당 용액 10 ppm 사용 시 가징 높은 항균력을 나타냈다. 0.015% 이상의 안식향산나트륨 참가 가능성 음료에서는 다섯 효모균 모두 증식이 관찰되지 않았다. 종합적으로 S. cerevisiae, Z. bailii, P. anomala의 저항성이 P. membranaefaciens, C. albicans 보다 낮았으며, 균주별 차이는 보였으나 allyl isothiocyanate, 올리고당, 자당지방산에스테르가 큰 항균력을 보였다. 본 연구결과는 기능성 음료의 합성 보존료를 대체할 수 있는 천연항균제의 개발 및 이용에 기초 자료로 활용될 수 있을 것이다.