• Journal of Environmental Health Sciences
• /
• v.13 no.1
• /
• pp.47-57
• /
• 1987

Owing to the modification of testing methods of disinfectants or antiseptics, variations of bacteria according to characteristics of regions and resistance changes of bacteria, it is necessary that the bactericidal activities of disinfectants or antiscptics should be reevaluated nowadays. This study was carried out to reevaluate in the vitro bactericidal activity of Chlorhexidine gluconate solution. The results of experiment were summarized as follows. 1. For Chlorhexidine gluconate solution, minimal inhibitory concentrations of total bacteria taken from sewage water and Legionella bozemanii were $2.0\times 10^{-3}$%, $1.0\times 10^{-2}$%, respectively and were comparatively high. Minimal inhibitory concentration of Shigella flexneri was $1.6\times 10^{-4}$%, and was comparatively low. 2. For total bacteria taken from sewage water, it was killed within 15 minute in 0.1% Chlorhexidine gluconate solution when number of cells was $1.6\times 10^7$/ml. 3. For 0.0125% Chlorhexidine gluconate solution, decimal reduction times of Ps. aeruginosa, S. typhi, E. Coli were 45 sec, 25 sec, 18 sec repectively. For 1%, 0.125% Chlorhexidine gluconate solution, decimal reduction times of Legionella bozemanii were 10 sec, 45 sec respectively. 4. There was significant difference in the bactericidal activity of Chlorhexidine gluconate solution according to temperattire. Phenol coefficient of Chlorhexidine gluconate solution as using Staph. aureus was 100 and comparatively higher than that of other disinfectants. In comparison with other disinfectants, Legionella bozemanii was killed within 5 minutes in 0.02% KMnO$_4$ and 0.125% Chlorhexidine giuconate solution but was not killed within 3 minutes in 1% 0-cresol, 1% Phenol.

• Mycobiology
• /
• v.36 no.4
• /
• pp.249-254
• /
• 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 Food Hygiene and Safety
• /
• v.24 no.3
• /
• pp.273-276
• /
• 2009

We investigated eight active natural antimicrobials for preservation of functional beverages that are usually degraded by yeasts rather than by bacteria due to a high sugar content and a low pH. Five strains of yeasts (S. cerevisiae, Z. bailii, P. membranaefaciens, C. albicans, and P Anomala) were tested with eight natural antimicrobial agents ($\varepsilon$-polylysine, yucca extract, vitamin $B_1$ derivative, scutellaria baicalensis extract, chitooligosaccharid, allyl isothiocyanate, sucrose-fatty acid ester, and oligosaccharide). The lowest minimal inhibitory concentrations (MIC) were 10 ppm for oligosaccharide and sucrose-fatty acid ester against S. cerevisiae and Z. bailii, 10 ppm for allyl isothiocynate against P. membranaefaciens and C. albican, and 10 ppm for allyl isothiocynate and oligosaccharide against P. anomala. No growth were observed for five kinds of yeasts in functional beverages containing sodium benzonate at concentration of 0.015% or higher. The resistance of S. cerevisiae, Z. bailii, and P. Anomala against natural antimicrobial agents was lower than those of P. membranaefaciens and C. albican. Allyl isothiocyanate, oligosaccharide, and sucrose-fatty acid ester showed the highest antimicrobial activities among the eight tested antimicrobials. These results can be applied to develop new natural antimicrobial agents to improve microbial quality of functional beverages.

• The Journal of the Korean Society for Microbiology
• /
• v.21 no.3
• /
• pp.375-380
• /
• 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.

• Journal of Korean Medicine Rehabilitation
• /
• v.23 no.3
• /
• pp.15-26
• /
• 2013

Objectives The aim of this study was to investigate antimicrobial activity of Huanggeumjakyak- tang water extract against MRSA. Methods The antibacterial activities of Huanggeumjakyak-tang were evaluated against 3 strains of Methicillin-resistant Staphylococcus aureus (MRSA) and 1 standard Methicillinsusceptible S. aureus (MSSA) strain by using the disc diffusion method, minimal inhibitory concentrations (MICs) assay, colorimetric assay using MTT test, checkerboard dilution test and time-kill assay was performed under dark. Results The MIC (minimum inhibitory concentration) of Huanggeumjakyak-tang water extract against S. aureus strains ranged from 1,000 to $2,000{\mu}g/ml$. So we confirmed that it has a strong antibacterial effect. Also the combinations of Huanggeumjakyak-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. Conclusions The results obtained in this study suggest that Huanggeumjakyak-tang water extract showed antibacterial effect against MRSA, and it also showed reducing effect on the side-effect problems that are the major weak points of traditional antibiotics.

• Journal of Life Science
• /
• v.25 no.1
• /
• pp.29-36
• /
• 2015

Prodigiosin, a member of natural red pigment family, is produced by Serratia marcescens, and characterized by a common pyrrolylpyrromethane skeleton. This pigment has been reported with the effects of anticancer, immunosuppressant, antifungal, and algicidal activities. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital infections. In this study, anti-MRSA properties of prodigiosin isolated from Serratia sp. PDGS 120915 were investigated. We identified and purified prodigiosin using high performance liquid chromatography (HPLC) and evaluated anti-MRSA activity. Purified prodigiosin inhibited the growth of MRSA. The minimum inhibitory concentrations (MICs) of prodigiosin were determined to $32{\mu}g/ml$ against the MRSA strains. Fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were indicated synergistic effects of prodigiosin on MRSA.

• YAKHAK HOEJI
• /
• v.29 no.3
• /
• pp.159-164
• /
• 1985

To investigate the susceptibility and resistance in case of simultaneous administrations of Lactobacilli and Clostridia prekparations with antituberculosis agents and antibiotics, five strains of Lactobacilli, i.e., Lactobacillus bulgaricus, L. casei, L. helveticus, L. acidophilus, L. sporogenes, and Clostridium butyricum were isolated from commercially available preparation. Minimal inhibitory concentrations (MIC) of nine antituberculosis agents and 21 antibiotics against these strains were determined. The results shwoed that these strains were very sensitive only to rifampicin among antituberculosis agents, and sensitive to other antibiotics. Since the simultaneous oral administration of rifampicin and other antibkiotics with these sensitive strains is ineffective, development of new resistant mutants is desirable.

• Journal of Korean society of Dental Hygiene
• /
• v.1 no.1
• /
• pp.101-109
• /
• 2001

This study was conducted to investigate the effect of natural resources against growth of oral bacteria. The CHJ-5 strain was isolated from oral cavity of dental patients. Similarity index values of oral bacterium CHJ-5 was 0.876 to E. faecalis by cellular fatty acid analysis(Analytical Services Inc., USA). As a result of investigation about the growth inhibition of 32 kinds of natural resources on E. faecalis CHJ-5. This strain was inhibited by Schizamdrae fructus, Coptidis rhizoma and Caryophylli flos. Minimal inhibitory concentrations of Schizamdrae fructus, Coptidis rhizoma and Caryophylli flos were 0.1%, 02% and 0.1% on E. faecalis CHJ-5, respectively.

• YAKHAK HOEJI
• /
• v.52 no.4
• /
• pp.274-278
• /
• 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 ${\mu}g/ml$).

• Natural Product Sciences
• /
• v.13 no.1
• /
• pp.85-89
• /
• 2007

To determine whether the essential oil from Coriandum sativum and its main component, linalool, exhibit antifungal activity, we employed a broth dilution assay and disk diffusion test using common pathogenic Candida and Trichophyton species. Both coriander oil and linalool significantly inhibited growth of the tested fungi, with minimal inhibitory concentrations (MICs) in the range of $0.03{\sim}2mg/ml$. Furthermore, in a checkerboard titer test, both the oil fraction and linalool exhibited synergism when combined with ketoconazole, with resultant FICIs ranging from 0.06 to 0.53. Notably, hyphal formation in C. albicans cells was obviously inhibited by C. sativum essential oil in this experiment.