• 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.

• 동의생리병리학회지
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• 제26권3호
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• pp.325-329
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• 2012

The present study investigated the antimicrobial properties of medicinal herbs including Scutellariae Radix (SR: dried root of Scutellariae bicalensis Georgi). Among hot-water extracts of medicinal herbs tested in this study, SR extract showed the most potent antimicrobial activity with minimum inhibitory concentration (MIC) of 0.625 mg/mL. In particular, synergistic effects of antimicrobial activity were observed upon combined application of SR and chitooligosaccharide as indicated by MIC of 0.125 mg/mL and FIC (fractional inhibitory concentration) index of 0.45. Thermal stability analysis indicated that the components responsible for antimicrobial activity was stable for 8 months at $45^{\circ}C$. Antimicrobial activity was proven to be effective in foods as well as in cosmetics as comparable to that of the chemical preservatives.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1288-1294
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• 2021

There are a growing number of reports of hospital-acquired infections caused by pathogenic bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). Many plant products are now being used as a natural means of exploring antimicrobial agents against different types of human pathogenic bacteria. In this research, we sought to isolate and identify an active molecule from Sedum takesimense that has possible antibacterial activity against various clinical isolates of MRSA. NMR analysis revealed that the structure of the HPLC-purified compound was 1,2,4,6-tetra-O-galloyl-glucose. The minimum inhibitory concentration (MIC) of different extract fractions against numerous pathogenic bacteria was determined, and the actively purified compound has potent antibacterial activity against multidrug-resistant pathogenic bacteria, i.e., MRSA and its clinical isolates. In addition, the combination of the active compound and β-lactam antibiotics (e.g., oxacillin) demonstrated synergistic action against MRSA, with a fractional inhibitory concentration (FIC) index of 0.281. The current research revealed an alternative approach to combating pathogenesis caused by multi-drug resistant bacteria using plant materials. Furthermore, using a combination approach in which the active plant-derived compound is combined with antibiotics has proved to be a successful way of destroying pathogens synergistically.

• 대한한방부인과학회지
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• 제25권1호
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• pp.34-46
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• 2012

Objectives: The object of this study was to observe the in vitro antibacterial effects of Wandae-tang extracts and combination of Wandae-tang extracts and Clindamycin against Gardnerella vaginalis ATCC14018. Methods: Antibacterial activities against Gardnerella vaginalis ATCC14018 of Wandae-tang extracts were detected using standard agar microdilution methods. In addition, the effects on the bacterial growth curve were also monitored at minimal inhibitory concentration(MIC) and $MIC{\times}2$ levels. The combination effects of Wandae-tang extracts with Clindamycin were observed by Checkerboard microtiter assay, and the effects of bacterial growth curve was treated with Wandae-tang extracts MIC+Clindamycin MIC, 1/2 MIC and 1/4 MIC, respectively. Results: MIC of Wandae-tang extracts and Clindamycin against Gardnerella vaginalis ATCC14018 were detected as $1.719{\pm}0.856$(0.782~3.125) $mg/m{\ell}$ and $0.010{\pm}0.006$ (0.004~0.016) ${\mu}g/m{\ell}$. In addition, Clindamycin and Wandae-tang extracts were also showed marked dosage-dependent inhibition of bacterial growth, and more dramatical inhibitions were detected in Clindamycin+Wandae-tang extracts MIC treatment. Fractional inhibitory concentration index in combination of Wandae-tang extracts and Clindamycin were detected as $0.294{\pm}0.052$(0.250~0.375) at Checkerboard microtiter assay. Conclusions: The results obtained in this study suggest that Wandae-tang extracts showed antibacterial effects against Gardnerella vaginalis ATCC14018, and they also showed dosage-dependent inhibitory effects on the bacterial growth. In addition, combination treatment of Wandae-tang extracts with Clindamycin showed more synergistically potent inhibitory effects on the growth of Gardnerella vaginalis.

• 한국동물위생학회지
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• 제40권3호
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• pp.219-225
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• 2017

This study was investigated the synergistic effects from the combination of cefalexin and gentamicin (CCG) against Staphylococcus spp. isolated from bovine milk. Minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) index were determined for 16 bacteria from 13 bovine farms in Gyeongsangnam province by the National Committee for Clinical Laboratory Standards broth microdilution procedure. Antimicrobial agents tested included cefalexin, gentamicin and CCG. Against Staphylococcus spp. tested, the MIC ranges of cefalexin, gentamicin and CCG were 0.25~1.0, 0.5~0.125 and $0.06{\sim}0.125{\mu}g/mL$, respectively. In addition, the FIC index ranges of CCG against most of the isolates was 0.28~0.43 and the FIC index of CCG against 2 strains of Staphylococcus haemolyticus (S. haemolyticus) was 0.59. In conclusion, CCG has a high antibacterial activity against Staphylococcus isolates, then the combination may be applied for the treatment of bovine mastitis caused by Staphylococcus spp.

• 대한약침학회지
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• 제25권2호
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• pp.101-105
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• 2022

Objectives: This study aims to determine the Fractional Inhibitory Concentration Index (FICI) of combinations of Melastoma malabathricum leaf fraction with ciprofloxacin or gentamicin against pathogenic bacteria, Escherichia coli, Staphylococcus aureus, and Bacillus cereus, isolated from Diabetic Foot Ulcer (DFU) patients. Methods: We tested concentrations of 45%, 55%, 65%, and 75% of gentamicin and ciprofloxacin using dilution and agar diffusion methods. The combination of M. malabathricum leaf extract with these antibiotics was tested in vitro against all three bacteria. Results: The combination of M. malabathricum leaf extract and ciprofloxacin gave a FICI value of 0.5, indicating synergistic antibacterial activity against the test bacteria. Conclusion: The results show that the antibacterial effect of a combination of high doses of the leaf extract with either antibiotic is greater than that of the leaf extract and the antibiotics in single use.

• 대한미생물학회지
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• 제21권3호
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• pp.375-380
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• 1986

Thirty-one strains of Pseudomonas aeruginosa were submitted to the synergistic activity test of amikacin(AK) and gentamicin(GM) combined with moxalactam(MX), ceftizoxime(CTZ) or cefoperazone(CFZ). The minimal inhibitory concentrations(MICs) of each drug and drugs combined in various ratios were measured by checkerboard dilution method. The synergism was determined through analysing the MIC distribution curve on isobologram and calculating the fractional inhibitory concentration index(FICI). MICs of GM, AK, MX, CFZ and CTZ against the 31 tested strains were distributed from $12.5{\mu}g/ml$ to $800{\mu}g/ml$, from $0.8{\mu}g/ml$ to $25{\mu}g/ml$, from $3.1{\mu}g/ml$ to $50{\mu}g/ml$, from $3.1{\mu}g/ml$ to $400{\mu}g/ml$, and from $12.5{\mu}g/ml$ to $100{\mu}g/ml$, respectively. The rate synergism of each drug combination by means of FICl was 45.5% in GM-MX, 36.4% in GM-CFZ, 63.6% in GM-CTZ, 48.6% in AK-MX, 35.3% in AK-CFZ, and 35.7% in AK-CTZ combination. Thus, it is suggested that Pseudomonas aeruginosa may effectively be inhibited by various aminoglycoside and cephalosporin combinations.

• 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.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.858-864
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• 2007

This study investigated the antibacterial activities of sophoraflavanone G from Sophora flavescens in combination with two antimicrobial agents against oral bacteria. The combined effect of sophoraflavanone G and the antimicrobial agents was evaluated using the checkerboard method to obtain a fractional inhibitory concentration(FIC) index. The sophoraflavanone G+ampicillin(AM) combination was found to have a synergistic effect against S. mutans, S. sanguinis, S. sobrinus, S. gordonii, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis, whereas the sophoraflavanone G+gentamicin(GM) combination had a synergistic effect against S. sanguinis, S. criceti, S. anginosus, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis. Neither combination exhibited any antagonistic interactions(FIC index>4). In particular, the MICs/MBCs for all the bacteria were reduced to one-half$\sim$one-sixteenth as a result of the drug combinations. A synergistic interaction was also confirmed by time-kill studies for nine bacteria where the checkerboard suggested synergy. Thus, a strong bactericidal effect was exerted through the drug combinations, plus in vitro data suggested that sophoraflavanone G combined with other antibiotics may be microbiologically beneficial rather than antagonistic.

• 대한본초학회지
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• 제30권5호
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.