• Fisheries and Aquatic Sciences
• /
• v.11 no.1
• /
• pp.1-6
• /
• 2008

In an effort to discover an alternative therapeutic agent against methicillin-resistant Staphylococcus aureus (MRSA), several medicinal plants and seaweeds were evaluated for its antibacterial activity against MRSA. A methanolic extract of the Phaeophyta Ecklonia stolonifera exhibited significant antibacterial activity against MRSA. To perform more detailed investigation on antibacterial activity, the methanol extract of E. stolonifera was further fractionated with organic solvents such as hexane, dimethylchloride, ethyl acetate, and n-butanol. Among them, the hexane fraction showed the strongest antibacterial activity against MRSA strains with MIC from 500 to $600 {\mu}g/mL$. The fraction also exhibited a bactericidal activity against MRSA, indicating that E. stolonifera contains a bactericidal substance against MRSA.

• Food Science and Biotechnology
• /
• v.18 no.5
• /
• pp.1263-1272
• /
• 2009

Danshen (Salvia miltiorrhiza Bunge) is a traditional Korean medicine that is commonly used for the treatment of inflammatory diseases such as edema, arthritis, hepatitis, and endangitis. The several extracts of danshen were tested for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) isolated in clinic by broth microdilution method, the checkerboard, and time-kill methods to evaluate the synergistic effects of the combination of the extracts with antibiotics. The chloroform ($CHCl_3$) and n-hexane (HEX) extracts [minimum inhibitory concentration (MIC), 0.0078-0.3125${\mu}g/mL$; minimum bactericidal concentration (MBC), 0.019-0.625${\mu}g/mL$] were found to have strong antibacterial activity against MRSA. Additionally, when the $CHCl_3$ and HEX extracts were co-administered with ampicillin or oxacillin, a synergistic effect against MRSA was observed. Furthermore, a time-kill study evaluating the effects of the extracts against MRSA indicated that treatment with the $CHCl_3$ extract in combination with ampicillin or oxacillin produced rapid bactericidal activity. These results suggest that danshen extracts may have potently antimicrobial activity and thus, it can be a suitable phytotherapeutic agent for treating MRSA infections.

• YAKHAK HOEJI
• /
• v.11 no.3_4
• /
• pp.17-21
• /
• 1967

At present, quarternary ammonium salts(cationic surfactant) and Tego compounds (amphoteric surfactant) are used as germicidal agent. In this paper, it was investigated whether their germicidal activities are influenced or not by some suspending agents which are added to them 0.005% benzalkonium chloride aq. solution and 0.05% dodecyl diaminoethyl glycine aq. solution sterilized respectively against Staphylococcus aureus and Escherichia coli within a minute. The solutions aded acacia, carboxymethyl cellulose, sodium alginate solutions to make to 0.005% to above surfactants solution decreased the germicidal activity, not being sterilized bacteria for more than 2 hours however, the solutions decreased the germicidal activity by addition of suspending agents such as acacia, carboxymethyl cellose, sodium alginate and bacteria were survival for more than 2 hrs, 0.05% of benzalkonium chloride and 0.1% dodecyl diaminoethyl glycine respectively would be sterilized within 10 minutes, when added to 5% suspending agents. This result show that bactericidal action of dodecyl diaminoethyl glycine is affected by suspending agents less than that of benzalkonium chloride.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.8
• /
• pp.1059-1064
• /
• 2014

Staphylococcus aureus is a major human pathogen, implicated in both community and hospital acquired infections. The therapy for methicillin-resistant Staphylococcus aureus (MRSA) infections is becoming more difficult because of multidrug resistance and strong biofilm-forming properties. Schiff bases have attracted attention as promising antibacterial agents. In this study, we investigated the in vitro activity of taurine-5-bromosalicylaldehyde Schiff base (TBSSB) against MRSA. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined using a microtiter broth dilution method. TBSSB effectively inhibited planktonic MRSA, with an MIC of $32{\mu}g/ml$. The time-kill curve confirmed that TBSSB exhibited bactericidal activity against MRSA. TBSSB was also found to significantly inhibit MRSA biofilm formation at 24 h, especially at $1{\times}MIC$ and sub-MIC levels. Furthermore, scanning electron microscopy and transmission electron microscopy showed remarkable morphological and ultrastructural changes on the MRSA cell surface, due to exposure to TBSSB. This study indicated that TBSSB may be an effective bactericidal agent against MRSA.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.554-557
• /
• 2000

Strain JV3 was isolated from commercial Swiss cheese products and identified as a bacteriocin producer, which has bactericidal activity against Leuconostoc mesenteroides KCCM 11324. Strain JW3 was identified tentatively as Lactococcus lactis by the API test. The activity of lacticin JW3, named tentatively as the bacteriocin produced by Lactococcus lactis JW3, was detected during the mid-log growth phase, and reached a maximum during the early stationary phase, and decreased after the late stationary phase. Its antimicrobial activity on sensitive indicator cells was completely disappeared by protease IV. The inhibitory activities of lacticin JW3 were detected during treatments of up to $121\'^{circ}C$ for 15 min. Lacticin JW3 was very stable over a pH range of 2.0 to 9.0 The apparent molecular mass of lacticin JW3 was estimated to be in the region of 3-3.5kDa, which was determined by the direct detection of bactericidal activity after SDS-PAGE.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.7
• /
• pp.1052-1061
• /
• 2019

Objective: This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens. Methods: Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity. Results: The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope. Conclusion: Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.

• 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.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.04a
• /
• pp.53-60
• /
• 2000

Strain BH5 was isolated from naturally fermented Kimchi and identified as a bacteriocin producer, which has bactericidal activity against Micrococcus flavus ATCC 10240. Strain BH5 was identified tentatively as Lactococcus lactis by the API test and some characteristics. Lactococcus lactis BH5 showed a broad spectrum of activity against most of the non-pathogenic and pathogenic microorganisms tested by the modified deferred method. The activity of lacticin BH5, named tentatively as the bacteriocin produced by Lactococcus lactis BH5, was detected at the mid-log growth phase, reached its maximum during the early stationary phase, and decreased after the late stationary phase. Lacticin BH5 also showed a relatively broad spectrum of activity against non-pathogenic and pathogenic microorganisms as tested by the spot-on-lawn method. Its antimicrobial activity on sensitive indicator cells was completely disappeared by protease XIV or ${\alpha}$-chymotrypsin. The inhibitory activities of lacticin BH5 were detected during treatments up to 100$^{\circ}C$ for 30 min. Lacticin BH5 was very stable over a pH range of 2.0 to 9.0 and was stable with all the organic solvents examined. The cell concentration and bacteriocin production in strain BH5 were maximum when grown at 30$^{\circ}C$ in a modified MRS medium supplemented with 0.5% tryptone, 1.0% yeast extract, and 0.5% beef extract as nitrogen sources. It demonstrated a typical bactericidal mode of inhibition against Micrococcus flavus ATCC 10240. Lacticin BH5 was purified through ammonium sulfate precipitation, ethanol precipitation, and CM-Sepharose column chromatography. The apparent molecular mass of lacticin BH5 was estimated to be in the region of 3.7 kDa, by the direct detection of bactericidal activity after SDS-PAGE. Mutant strain NO141 which was isolated by nitrosoguanidine mutagenesis produced about 4 fold more bacteriocin than the wild type.

• YAKHAK HOEJI
• /
• v.10 no.2_3
• /
• pp.15-19
• /
• 1966

In order to find 2-(5-nitro)furylacrylic acid derivatives possessing antimicrobial activity, nine new 2-(5-nitro)furylacrylamino acids were synthesized which were obtained by the action of 2-(5-nitro)furylacryla chloride on amino acids, such as $_{L}$-phenylalanine, glycine, $_{L}$-isoleucine, $_{L}$-glutamic acid, $_{DL}$-methionine, $_{L}$-threonine, $_{L}$-valine, $_{L}$-tryptophan and $_{DL}$-alanine, according to Schotten-Baumann method. These compounds generally showed a good bactericidal and bacteriostatic activity against Bacillus subtilis but were less effective against staphylococcus aureus, Proteus vulgaris and Escherichia coli. Of the above nine compounds, 2-(5-nitro)furylacryl glycine exhibited a good bactericidal activity.

• Journal of Food Hygiene and Safety
• /
• v.10 no.1
• /
• pp.23-28
• /
• 1995

The effect of the ethanol extract from salviae miltiorrhizae radix (Salvia miltiorrhiza) on the microbial growht and the stability of the extracted antimicrobial material were investigated. The ethanol extract had strong growth inhibition activity (MIC, 3.13~50.0 $\mu\textrm{g}$/ml) against Gram-positive bacteria such as B. subtilis, L. monocytogenes and S. aureus. Among Gram-positive bacteria tested, B. subtilis was the most susceptible to the extracted substance. While the antimicrobial activity of the ethanol extract was weak (MIC, 400~800 $\mu\textrm{g}$/ml) to E. coli and yeasts (C. albicans, Sacch. diastaticus). The ethanol extract had bactericidal action at higher concentration than MIC against B. subtilis, while the extract had only bacteriostatic action against S. aureus. The extracted antimicrobial substance was stable in the pH range of 4.0 to 10.0, heat treatment at 121$^{\circ}C$ for 15 min, and freezing and thawing