• Journal of Veterinary Science
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• v.19 no.6
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1656-1666
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• 2021

Dental pathogens lead to chronic diseases like periodontitis, which causes loss of teeth. Here, we examined the plausible antibacterial efficacy of copper nanoparticles (CuNPs) synthesized using Cupressus macrocarpa extract (CME) against periodontitis-causing bacteria. The antimicrobial properties of CME-CuNPs were then assessed against oral microbes (M. luteus. B. subtilis, P. aerioginosa) that cause periodontal disease and were identified using morphological/ biochemical analysis, and 16S-rRNA techniques. The CME-CuNPs were characterized, and accordingly, the peak found at 577 nm using UV-Vis spectrometer showed the formation of stable CME-CuNPs. Also, the results revealed the formation of spherical and oblong monodispersed CME-CuNPs with sizes ranged from 11.3 to 22.4 nm. The FTIR analysis suggested that the CME contains reducing agents that consequently had a role in Cu reduction and CME-CuNP formation. Furthermore, the CME-CuNPs exhibited potent antimicrobial efficacy against different isolates which was superior to the reported values in literature. The antibacterial efficacy of CME-CuNPs on oral bacteria was compared to the synergistic solution of clindamycin with CME-CuNPs. The solution exhibited a superior capacity to prevent bacterial growth. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and fractional inhibitory concentration (FIC) of CME-CuNPs with clindamycin recorded against the selected periodontal disease-causing microorganisms were observed between the range of 2.6-3.6 ㎍/ml, 4-5 ㎍/ml and 0.312-0.5, respectively. Finally, the synergistic antimicrobial efficacy exhibited by CME-CuNPs with clindamycin against the tested strains could be useful for the future development of more effective treatments to control dental diseases.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.119-124
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• 2022

Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical opportunistic pathogens. Moreover, these bacteria are known to possess multidrug-resistant (MDR) properties. This study investigates the antimicrobial activity of six fermented products, which have varying efficacies against P. aeruginosa, E. coli, and S. aureus. To identify novel candidate genes, differential expression analysis was performed using an annealing control primer. In the disk diffusion method, Fig vinegar (FV) and Diospyros kaki Thunb vinegar (DTV) showed the greatest increase in inhibition compared to other fermented products, whereas fermented Korean traditional nature herb (FKTNH) had no antibacterial effect. This study identified down-regulation of Escherichia coli O157:H7 ompW gene for outer membrane protein W, whereas gene for synthetic construct Lao1 gene for L-amino acid oxidase were up-regulated in E. coli treated with 5% FV. Consuming fermented vinegar helps prevent bacterial infections. Especially, FV and DTV are potentially useful alternative natural products for multidrug resistance. Furthermore, both are expected to be used as effective natural antimicrobial agents, such as disinfectants.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.31-38
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• 1990

Cryptosporidium, a coccidian parasite first described by Tyzzer (1907) from a laboratory mouse, has become an important human enteric pathogen causing overwhelming diarrhea especially in immunocompromised patients such as AIDS. This parasite has been reported from over 20 countries and is recognized as a cosmopolitan species. In Korea, however, thEre has been no report on human as well as animal cryptosporidiosis. This study was performed so as to verify the presence of Cryptosporidium in Korea by activating the parasite from laboratory mice by immunosuppression. Total 65 conventionally.bred ICR mice including a control (5 mice) and 3 experimental groups (20 each) were used for this study. Group I was immunosuppressed with Prednisolone injection (1 mg IM, every other day) for 7 weeks. Group II (prednisolone injection and tetracycline administration) and Group III. (prednisolone injection and trimethoprim-sulfamethoxazole administration) were prepared to observe the effect of antibacterial agents on the activation of cryptosporidiosis. In fecal examinations of mice Cryptosporidium oocysts($4-6{\mu\textrm{m}}$ in size) were detected from 1 week after the start of immunosuppression and the mice began to die. In H-E stained tissue sections of the lower jejunum, numerous very small ($2~4{\;}{\mu\textrm{m}}$), dense, ovoid or spherical, slightly basophilic bodies were seen attached on the free border of mucosal epithelial cells. In scanning and transmission electron microscopic observations, these organisms were identified as various developmental stages of Cryptosperidium. The species is considered to be C. parvum. Cryptosporidiosis was activated not only in Group I but also in Group II and III, indicating no protective effects of the antibacterial agents used, although the mice in Group II and III lived longer than those in Group I. The present study confirmed that Cryptosporidium exists in laboratory mice bred in Korea, and predicts possible occurrence of human cryptosporidiosis in Korea.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.386-396
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• 2013

Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide ($H_2O_2$) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion ($O_2{^-}$) and $H_2O_2$ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of $H_2O_2$ and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both $H_2O_2$ and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by $10^6$ and $10^7$ cfu/ml of R. solanacearum. $H_2O_2$- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by $H_2O_2$ and/or SNP with untreated control. Neither $H_2O_2$ nor SNP protect the tomato seedlings from the bacterial wilt, but $H_2O_2$ + SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that $H_2O_2$ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.386-392
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• 2014

The present study was aimed at investigating the antimicrobial activities of licorice's active ingredients. Four samples of licorice ingredients (glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin) were evaluated for their antimicrobial activities against six skin microorganisms. The bioassay applied for determining the antimicrobial effects employed a disc diffusion assay, the minimum inhibitory concentration, and the challenge test. The ingredients showed antibacterial activities. Especially, isoliquiritigenin has significant antimicrobial activities against two Gram-positive (Bacillus subtilis, Propionobacterium acnes) and two Gramnegative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much higher antimicrobial activities than synthetic preservatives. Our results reveal that liquiritigenin and isoliquiritigenin could be useful compounds for the development of antibacterial agents for the preservation of cosmetics and foods. The two flavonoids, liquiritigenin and isoliquiritigenin, sourced from Korea, China, Uzbekistan, were quantified using HPLC. The results demonstrated that Korean licorice has two flavonoids (liquiritigenin, isoliquiritigenin) in much higher quantities than was observed in the licorice obtained from the two other countries. Thus, isoliquiritigenin and Korean licorice extract represent new candidates for antimicrobial agents.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.1
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• pp.1-24
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• 2013

Objectives: The object of this study was to observe the protective effect of Gamijipaesan aqueous extracts(GJS), which has been traditionally used in Korean medicine in obstetrics & gynecological fields as anti-infectious and anti-inflammatory agents, against mastitis induced by Staphylococcus aureus infection in a rat model through antibacterial, antiinflammatory, immunomodulatory, and anti-oxidant effects. Methods: Antibacterial activities of GJS against S. aureus were detected using standard agar microdilution methods, with the effects on the bacterial invasion and intracellular killing of individual test materials in human mammary gland carcinoma cell(MCF-7) and murine macrophages(Raw 264.7) at MIC1/2, MIC and MIC2 concentration levels. In addition, the effects on the cell viability, nitric oxide(NO), tumor necrosis factor(TNF)-${\alpha}$ and interleukin (IL)-6 productions of LPS activated Raw 264.7 cells. The changes on the mammary tissue viable bacterial numbers, myeloperoxidae(MPO), inducible nitric oxide synthetase(iNOS), TNF-${\alpha}$ and IL-6 contents were observed in the S. aureus in vivo intramammary infectious rat model. The anti-bacterial and anti-inflammatory effects were compared with ciprofloxacin and piroxicam, respectively in the present study. Results: MIC of GJS and ciprofloxacin against S. aureus were detected as $0.860{\pm}0.428$ (0.391-1.563) mg/ml and $0.371{\pm}0.262$(0.098-0.782) ${\mu}g/ml$, respectively. In addition, GJS and ciprofloxacin were also showed marked dosage-dependent inhibition of the both bacterial invasion and intracellular killing assays using MCF-7 and Raw 264.7 cells at MIC1/2, MIC and $MIC{\times}2$ concentrations, respectively. $ED_{50}$ against LPS-induced cell viabilities and NO, TNF-${\alpha}$ and IL-6 releases of GJS were detected as 0.72, 0.04, 0.08 and 0.11 mg/ml, and as 19.04, 4.18, 5.37 and 4.27 ${\mu}g/ml$ in piroxicam, respectively. 250 and 500 mg/kg of GJS also inhibit the intramammary bacterial growth, MPO, iNOS, TNF-${\alpha}$ and IL-6 contents in S. aureus in vivo intramammary infected rats, respectively. GJS 500 mg/kg showed quite similar antibacterial and anti-infectious effects as compared with ciprofloxacin 40 mg/kg and also showed similar anti-inflammatory effects as piroxicam 10 mg/kg, in S. aureus in vivo intramammary infectious models. Conclusions: The results obtained in this study suggest that over 250 mg/kg of GJS showed favorable anti-infectious effects against S. aureus infection in a rat model through their antibacterial, anti-inflammatory, immunomodulatory and anti-oxidant effects and therefore expected that GJS can be used as alternative therapies, having both anti-inflammatory and anti-infectious activities. However, more detail mechanism studies should be conducted in future with the efficacy tests of individual herbal composition of GJS and the screening of the biological active compounds in individual herbs. In the present study, GJS 500 mg/kg showed quite similar anti-infectious effects were detected as compared with ciprofloxacin 40 mg/kg treated rats, and also GJS shows quite similar anti-inflammatory effects as compared with piroxicam 10 mg/kg in S. aureus in vivo intramammary infectious rats, but ciprofloxacin did not showed any anti-inflammatory effects, and piroxicam did not showed anti-infectious effects in this study.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.1-14
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• 2005

The maintenance of good oral health in adults is often hindered by oral malodor and periodontal diseases which are known to be commonly caused by some species of Gram-negative anaerobic bacteria, with low sensitivity to common synthetic antibiotics or antibacterial chemical agents. Therefore the development of a nonharmful natural antibacterial oral rinsing remedy against the causative bacteria is thought to be very important. The purpose of this study is to obtain the basic data for development of a nonharmful natural antibacterial oral rinsing remedy using colloidal silver. The author applied colloidal silver solution with concentration of 10, 30, 50, 80 ppm to some strains in species of Prevotella intermedia, Porphyromonas gingivalis, Fusobaterium nucleatum, and evaluated the effects of colloidal silver on the growth of experimental bacterial strains in aspects of minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and growth pattern after incubation for 24, 48, 72 hours. The obtained results were as follows: MIC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 10 or 30 ppm in P. gingivalis, and 30, 50, or 80 ppm in F. nucleatum. And MBC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 30 or 50 ppm in P. gingivalis, 30 or 80 ppm in F. nucleatum. Therefore it was concluded that colloidal silver exhibited bacteriostatic or/and bacteriocidal effects against some experimental strain. And the inhibition of growth of experimental strains were markedly or considerably exhibited under 30 ppm$\sim$50 ppm of colloidal silver solution for 48 hours$\sim$72 hours in P. intermedia, 10 ppm$\sim$30 ppm for 24 hours$\sim$48 hours in P. gingivalis, 30 ppm for 24 hours in F. nucleatum. These results indicate that the colloidal silver inhibited effectively the growth of some species of Gram-negative anaerobic bacteria by exhibition of bacteriostatic or/and bacteriocidal effects, and can be used as a possible major ingredient of the nonharmful natural antibacterial oral rinsing remedy to oral malodor and periodontal diseases.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.99-103
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• 2007

The antibacterial efficacy of 0.1% (w/v) chitosan solution against Staphylococcus intermedius isolated from a dog with superficial pyoderma was evaluated in vitro and in vivo. The exposure time for the 0.1% chitosan solutions at different pH to be able to eliminate the bacterial cells and the effect of pH of the solutions on antibacterial activity was tested at the same time in vitro. The antibacterial activity of chitosan was compared to other antibacterial agents including 2.5% benzoyl peroxide, 0.5% chlorhexidine acetate, 0.1% chitosan solution combined with 2.5% benzoyl peroxide and chitosan combined with 0.5% chlorhexidine using a modified detergent scrub quantitative technique in 10 adult mongrel dogs in vivo. They were able to eliminate a number of bacteria after the exposure time of 10 minutes at varying degrees according to the pH of the solutions. The antibacterial activity of chitosan was inversely affected by pH with higher activity at lower pH value. The 0.1% chitosan solution was also efficacious against Staphylococcus intermedius in vivo. The combinations of chitosan with benzoyl peroxide and with chlorhexidine were shown to exert higher activity when compared to those of chitosan alone and benzoyl peroxide or chlorhexidine alone. The 0.1% chitosan solution was considered to be efficacious against Staphylococcus intermedius isolated from a dog with superficial pyoderma in both in vivo and in vitro and have a potential for the clinical applications in the treatment or pyoderma in dogs.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.57-63
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• 2010

To develop natural therapeutic agents for acne vulgaris, we investigated antibacterial and anti-inflammatory effects of various medicinal plant extracts. Among candidate extracts, we selected Psoralea corylifolia L. extract (AC-1) and Magnoliae officinalis extract (AC-2) which showed the relatively high antibacterial effects, and Inula helenium L. extract (ACF-1) and Chrysanthemum zawadskii var. latilobum extract (ACF-2) which showed the relatively high anti-inflammatory effects for further investigations. All of them did not show cytotoxic effects below the concentration of $50{\mu}g/mL$. The antibacterial effects of AC-1, AC-2 and extract complex (AC) against P. acnes were 2.8, 2.5 and 3.2 times higher than that of 10 % salicylic acid respectively. And the antibacterial effect of AC-2 and extract complex against S. aureus were 1.4 and 1.5 times higher than that of 10 % methylparaben respectively. Also, it was shown that ACF-1, ACF-2 and extract complex had anti-inflammatory effects. All of them exhibited inhibitory effects for the secretion of IL-8 and TNF-$\alpha$ from THP-1 cells activated by heat-killed P. acnes. They reduced about 27 %, 38 %, 44 % of IL-8 secretion and 90 %, 88 %, 90 % of TNF-$\alpha$ secretion at concentration of $50{\mu}g/mL$ respectively. These results showed that the complex of medicinal plant extracts, AC-1. AC-2, ACF-1, and ACF-2, had therapeutic effects to acne vulgaris through antibacterial and anti-inflammatory effects. Therefore, we suggest that extract complex of AC-1, AC-2, ACF-1 and ACF-2 may be used as a useful agent for development of natural cosmetics which have therapeutic effects to acne vulgaris.