• 대한수의학회지
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• 제14권2호
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• pp.237-241
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• 1974

A number of chemotherapeutic agents, namely antibiotics, sulfonamides and nitrofuran derivatives have been used, as a fred additive, for the purposes of growth improvement of chicken, increase of feed efficiency, decrease of animal mortality, and disease prevention. In these experiments, furamizole which is one of nitrofuran derivatives and feed additive was test, in field, its antibacterial activity against Mycoplasma gallisepticum causing air sac disease, its effect on pullorum disease control, its effect on the lowering the mortality of chicken and finally the increase of feed efficiency. Throughout the studies, furamizole, in concentration of 0.025% in feed fed to baby chicken continuously resulted as following: 1. Tested chicken showed no avian mycoplasma infection compared to 3.7% outbreak in control chicken. 2. Tested chicken showed a low degree of outbreak of pullorum disease. However, its outbreak was much more surpresed compared to that of control chicken. 3. Total mortality rate of 5.5% and 30.8% were obtained in test and control chicken respectively. 4. Feed efficiency were 2.83 and 2.97 in test and control chicken respectively.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.353-358
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• 1996

E. coli 11 and E. coli 101, clinical isolates of Escherichia coli were resistant to various quinolones, especially MICs to norfloxacin of both strains were higher than 100 mg/ml. In the presence of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler, norfloxacin uptake in both strains was increased, suggesting that an efflux system play an important role in the norfloxacin resistance. Outer membrane proteins of the susceptible and resistant strains which could affect the route of norfloxacin entry into cells were different. When quinolone resistance determining region(QRDR) of gyrA was amplified using PCR and cut with Hinf I, QRDR in the susceptible strain yielded two fragments while QRDRs in E. coli 11 and E. coli 101 yielded only one uncut fragment. When DNA sequence of QRDR was analyzed, there were two mutations as Ser-83 and Asp-87 in both resistant strains. these residues were changed to Leu-83 and Asn-87, respectively. These results showed that the norfloxacin resistance of E. coli 11 and E. coli 101 was resulted from multiple changes-an altered DNA gyrase A subunit, a change in route of drug entry, and reduction in quinolone concentration inside cells due to an efflux system.

• 복식문화연구
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• 제10권5호
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• pp.578-589
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• 2002

The purpose of this research was to analyze the residual water retention and to determine the number and species of microorganisms from the wet cotton fabrics in dehydration and drying process during washing. The drying rates of terrycloth and interlock knit under the rainy seasons were measured according to the dehydration and hanging methods, layers of fabric and pre-treatment agents. Microorganisms were isolated from the dried terrycloth by pure culture, and were identified by Biolog system. The results are as follow: The initial water retention of fabrics after dehydration decreased in the order of dripping>centrifuge>squeezing method, which affected the drying rate. The drying rates were faster by increasing surface area of fabrics. There was no significant difference in drying rate among the fabrics pre-treated with detergent, or fabric softener, or cationic surfactants such as Cetyltrimethylammonium bromide(CTAB) and Benzalkonium chloride(BC). Puedomonas aureginosa was found in the fabrics treated with a powder-type detergent. On the other side, there was no growth of microorganism in the fabrics treated with a liquid-type detergent (containing antibacterial agent), CTAB and BC.

• Food Science and Biotechnology
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• 제18권3호
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• pp.755-760
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• 2009

The growth-inhibiting activities of persimmon roots-derived materials against intestinal bacteria were evaluated and compared with that of 1,4-naphthoquinone as a positive control. The active constituent isolated from persimmon roots was characterized as 5-hydroxy-2-methyl-1,4-naphthoquinone using various spectroscopic analyses. Treatment with 1,4-naphthoquinone at a dose of 1.0 mg/disc strongly inhibited the growth of 6 intestinal bacteria. Furthermore, when the structure-activity relationships of 1,4-naphthoquinone's derivatives were evaluated, 5-hydroxy-2-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone were found to strongly inhibit the growth of Clostridium difficile, Clostridium perfringens, and Escherichia coli without adversely affecting the growth of Bifidobacterium adolescentis, Bifidobacterium longum, and Lactobacillus acidophilus. Additionally, 2-hydroxy-1,4-naphthoquinone and 5-hydroxy-1,4-naphthoquinone strongly inhibited the growth of C. difficile and C. perfringens, but did not inhibit the growth of E. coli. Taken together, these results indicate that persimmon roots-derived materials and some of 1,4-naphthoquinone's derivatives could be useful preventive agents against diseases caused by harmful intestinal bacteria.

• 한국식품영양과학회지
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• 제28권3호
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• pp.526-533
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• 1999

Two species of antimicrobial agent producing bacteria and one sensitive strain were isolated from soil. Those were identified as B. subtilis, B. licheniformis, and Curtobacterium sp. by morphological, biochemical, physiological and chemotaxonomic characteristics. These were designated as B. subtilis cx1, B. licheniformis cy2 and Curtobacterium sp. cf3, respectively. Antimicrobial agent produced by B. subtilis cx1 showed high antibacterial activity against gram positive bacteria including of B. subtilis, Curtobacterium sp., L. mesenteroids, Staphy. aureus, S. faecalis and even gram negative bacteria, P. aeruginosa. Antimicrobial agent from B. licheniformis cy2 showed slightly lower antimi crobial activity than that from B. subtilis cx1. These two strains showed maximum production of antimicrobial agents at 30oC for 9~21hr cultivation. Curtobacterium sp. cf3 showed more sensitive activity than a sensitive strain of B. subtilis ATCC 6633 which was same genus or species with the B. subtilis cx1 and B. subtilis cy2, when the antimicrobial agent producing strains, B. subtilis cx1 and B. subtilis cy2, were directly applied onto these sensitive lawns.

• 펄프종이기술
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• 제33권3호
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• pp.69-74
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• 2001

Diaper rash is found on the skin inside of babys diaper area. Most diaper rashes are caused by prolonged contact with the moisture, germs, and ammonia of the stool and urine. Some diaper rashes are caused by fungi infection such as candida albicans and Preteus vulgaris. In this study, Candida albicans was used as a test microorganism and experiment was carried out to inhibit diaper rash. Handsheets were treated with chitosan oligosaccharide, bamboo extractives, as well as mixture of monolaurin as an emulsifier and bamboo extractives. Both shake flask method and halo test were applied in order to examine the antimicrobial activity of each sample. It was found from both results of the halo test and shake flask method that handsheets treated with chitisan oligosaccharide or bamboo extractives showed antimicrobial property. In the treatment of bamboo extractives without emulsifier, no distinct difference in antimicrobial effect was found between bamboo branch and bamboo leaves extractives. In case of mixture of bamboo extractives and emulsifier, the result also suggested that bamboo branch showed better syngergistic effect than bamboo leaves. Both chitosan oligosaccharide and bamboo extractive can be used as antifungal agents against Candida albicans for making diaper.

• 한국자원식물학회지
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• 제31권6호
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• pp.719-724
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• 2018

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for a number of infections in humans that are difficult to treat, and as a result, is a substantial contributor to morbidity and mortality. In the present study, in search of natural products capable of inhibiting this multidrug-resistant bacterium, we investigated the antimicrobial activity of Lysimachia clethroides Duby root. The antibacterial activities of EtOH extract of Lysimachia clethroides Duby root and its n-hexane, EtOAc, n-BuOH and water fractions were evaluated against 15 strains of methicillin-resistant staphylococcus aureus (MRSA) and 1 standard methicillin-susceptible S. aureus (MSSA) strain by using the minimal inhibitory concentrations (MICs) assay, colorimetric assay using MTT test, checkerboard dilution test. Antimicrobial activity of n-hexane fraction of Lysimachia clethroides Duby root was remarkable. Against the 16 strains, the minimum inhibitory concentrations (MICs) were in the range of $31.25-62.5{\mu}g/ml$ and FICI values for n-hexane fraction of Lysimachia clethroides Duby root+AM and n-hexane fraction of Lysimachia clethroides Duby root+OX were checkerboard method performed using the MRSA, MSSA and one clinical isolate strains via MICI 0.12-1 and 0.25-0.75, showing the increase of synergistic effect. When combined together, these antibiotic effects were dramatically increased. These effective combinations could be new promising agents in the management of MRSA.

• The Plant Pathology Journal
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• 제38권1호
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• pp.25-32
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• 2022

Plant pathogens pose major threats on agriculture and horticulture, causing significant economic loss worldwide. Due to the continuous and excessive use of synthetic pesticides, emergence of pesticide resistant pathogens has become more frequent. Thus, there is a growing needs for environmentally-friendly and selective antimicrobial agents with a novel mode of action, which may be used in combination with conventional pesticides to delay development of pesticide resistance. In this study, we evaluated the potentials of lichen substances as novel biopesticides against eight bacterial and twelve fungal plant pathogens that have historically caused significant phytopathological problems in South Korea. Eight lichen substances of diverse chemical origins were extracted from axenic culture or dried specimen, and further purified for comparative analysis of their antimicrobial properties. Usnic acid and vulpinic acid exhibited strong antibacterial activities against Clavibacter michiganensis subsp. michiganensis. In addition, usnic acid and vulpinic acid were highly effective in the growth inhibition of fungal pathogens, such as Diaporthe eres, D. actinidiae, and Sclerotinia sclerotiorum. Intriguingly, the growth of Rhizoctonia solani was specifically inhibited by lecanoric acid, indicating that lichen substances exhibit some degrees of selectivity to plant pathogens. These results suggested that lichen substance can be used as a selective biopesticide for controlling plant disease of agricultural and horticultural significance, minimizing possible emergence of pesticide resistant pathogens in fields.

• 대한약침학회지
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• 제25권2호
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• pp.79-87
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• 2022

Since ancient times, plants have been a major source of novel drug molecules and have been used in the treatment of different infectious diseases. Secondary plant metabolites have miraculous healing properties and show potent therapeutic responses when used in combination drug therapy. The prime objective of this review is to summarize the concept of drug combination with special emphasis on the synergistic interactions between plant-derived bioactive phytochemicals with commercially available antimicrobial agents. The study also assesses the roles, importance, and applicability of phytochemicals in the management of different diseases. The review focuses on different aspects of combined antimicrobial activities, the possible mechanisms involved, and the current status of research in the field. The study was conducted based on an extensive literature survey that resulted in the following hypothesis: secondary metabolites derived from plants possess remarkable therapeutic activities. The study was designed as a systematic review that ensures unbiased and accurate representations of the relevant data and information. Jadad scale selection criteria were used for qualitative analysis of the articles to assess them based on the relevant secure score (minimum and maximum scores range between 1 and 5, respectively). Articles with secure scores > 3 were considered for the study. A comprehensive literature survey was conducted using resource databases including PubMed, Google Scholar, Bielefeld Academic Search Engine, Research Gate, Scopus, Medline, and Science Direct up to June 2019. This article contains concise information about the most commonly used bioactive phytochemicals with potent antifungal and antibacterial effects.

• Journal of Veterinary Science
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• 제23권2호
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• pp.23.1-23.15
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• 2022

Background: Antibacterial agents play important roles in the treatment of bacterial infections. However, the development of antimicrobial resistance (AMR) and carry-over of substances into the environment are several problems arising during oral treatment of bacterial infections. We assessed AMR development in commensal Escherichia coli (E. coli) in enrofloxacin treated and untreated animals. In addition, we examined fluoroquinolone in the plasma and urine of treated and untreated animals, and in sedimentation dust and aerosol. Methods: In each trial, six pigs were treated with enrofloxacin via powder, granulate or pellet forms in two time periods (days 1-5 and 22-26). Four pigs served as untreated controls. The minimum inhibitory concentration (MIC) was determined to evaluate AMR development. Analysis of enro- and ciprofloxacin was performed with high performance liquid chromatography. Results: Non-wildtype E. coli (MIC > 0.125 ㎍/mL) was detected in the pellet treated group after the first treatment period, whereas in the other groups, non-wildtype isolates were found after the second treatment period. E. coli with MIC > 4 ㎍/mL was found in only the pellet trial. Untreated animals showed similar susceptibility shifts several days later. Bioavailability differed among the treatment forms (granulate > pellet > powder). Enro- and ciprofloxacin were detected in aerosols and sedimentation dust (granulate, powder > pellet). Conclusions: This study indicates that the kind of the oral dosage form of antibiotics affects environmental contamination and AMR development in commensal E. coli in treated and untreated pigs.