• 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.

• 한국식품영양학회지
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• 제12권3호
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• pp.271-278
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• 1999

We isolated activnmycetes LAM-98-80 as strain producing an effective antibiotic for cephalosporin re-sistant pathogenic PSeudomonas sp. and identified as Streptomyces sp. LAM-98-80 from cultural and phyisological characteristics. We investigated the optimal culture conditions for producation of an anti-biotic becoming effective for cephalsporin-resistant pathogenic Pseudomonas sp. It was found that 1.5% soluble starch and 1.0% yeast extract were good as carbon and nitrogen source respectively. The pro-duction of antibiotic was also activated by 0.04% Mn2+ as 80% degree. The optimum initial pH on pro-ductio of antibiotic was pH 7.0. The culture condition for the maximal productivity of the antibiotic was at 3$0^{\circ}C$ for 5 days. The cephalosporin-resistant pathogenic Pseudomonas sp. as test bacteria was rev-ealed to resist antibiotic of cepha families but revealed to not resist those of $\beta$-lactam families ampicil-lin and amoxicillin. Parital purified antibiotic was stable for the pH from 3 to 9 and was also stable when treated at 70 $^{\circ}C$ for 1 hour, This antbiotic was effective against all gram positive and negative bac-teria but was not effective against molds and yeasts.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2043-2050
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• 2016

Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii. Nineteen multidrug-resistant A. baumannii strains were clinically isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii. The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis. Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

• 한국환경보건학회지
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• 제41권1호
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• pp.40-48
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• 2015

Objectives: This study aims to understand the concentration, diversity, and antibiotic characteristics of oxytetracycline resistant bacteria present in a surface water environment. Methods: Water sampling was performed in Cheongmi Stream in Gyeonggi-do, Korea in February and August 2014. Water samples collected from two sites were plated in triplicate on tryptic soy agar plates with 30 mg/L of oxytetracycline. Oxytetracycline resistant bacteria were selected from surface water in Cheongmi Stream and were subjected to 16S rDNA analysis for oxytetracycline resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Results from this study indicate that the dominant resistant organisms in this aquatic environment are from family Acinetobacter and family Aeromonas. As to culturable heterotrophic bacteria, Oxytetracycline resistant bacteria were present 0.45-0.93% during winter and 0.08-0.38% during summer. Most oxytetracycline resistant bacteria exhibited resistance to more than ten of the antibiotics studied. The diversity of oxytetracycline resistant bacteria in winter was higher than in summer. Conclusion: Most of these resistant bacteria are Gram negative and are closely related to pathogenic species. These results suggest that increasing multi-antibiotic resistant bacteria in the surface water environment has a close relation to the reckless use of antibiotics in livestock.

• 한국환경보건학회지
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• 제42권6호
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• pp.409-418
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• 2016

Objectives: The purpose of this study was to characterize penicillin G resistant bacteria in surface water from pharmaceutical complex effluent. Methods: Surface water was sampled from pharmaceutical complex effluent in Gyeonggi-do Province, Korea in March 2015. Water samples were plated in triplicate on tryptic soy agar plates with 32 mg/L of penicillin G. Penicillin G resistant bacteria were selected from the effluent and subjected to 16S rRNA analysis for the penicillin G resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Penicillin G resistant bacteria were present at 8.0% in terms of culturable heterotrophic bacteria. Identified penicillin G resistant bacteria exhibited resistance to more than nine of the antibiotics studied. These resistant bacteria are gram negative and are closely related to pathogenic species. Conclusion: Multi-antibiotic resistant bacteria in the surface water of pharmaceutical complex effluent suggest the need for disinfection and advanced oxidation processed for pharmaceutical effluent.

• 한국식품영양학회지
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• 제13권1호
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• The Plant Pathology Journal
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• 제36권3호
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• pp.204-217
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• 2020

In nature, plants are always under the threat of pests and diseases. Pathogenic bacteria are one of the major pathogen types to cause diseases in diverse plants, resulting in negative effects on plant growth and crop yield. Chemical bactericides and antibiotics have been used as major approaches for controlling bacterial plant diseases in the field or greenhouse. However, the appearance of resistant bacteria to common antibiotics and bactericides as well as their potential negative effects on environment and human health demands bacteriologists to develop alternative control agents. Bacteriophages, the viruses that can infect and kill only target bacteria very specifically, have been demonstrated as potential agents, which may have no negative effects on environment and human health. Many bacteriophages have been isolated against diverse plant-pathogenic bacteria, and many studies have shown to efficiently manage the disease development in both controlled and open conditions such as greenhouse and field. Moreover, the specificity of bacteriophages to certain bacterial species has been applied to develop detection tools for the diagnosis of plant-pathogenic bacteria. In this paper, we summarize the promising results from greenhouse or field experiments with bacteriophages to manage diseases caused by plant-pathogenic bacteria. In addition, we summarize the usage of bacteriophages for the specific detection of plant-pathogenic bacteria.

• 한국미생물·생명공학회지
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• 제30권2호
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• pp.129-134
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• 2002

토종닭 소장으로부터 가축 소화기 병원성 유해세균의 분리를 위하여 무작위 선별법과 중층-도말법을 사용하여 총130주의 유산균을 1차 분리하였다. 1차 분리한 130주를 paper disc법을 사용하여 최종적으로 살모넬라 균, 포도상구균, 대장균에 대하여 저해능이 우수한 7주를 분리하였다. 분리 균주의 동정을 위하여 1차로 API CHL kit를 사용하였고, 동정의 정확성을 높이기 위하여 2차로 16S rRNA sequencing 방법을 사용하였다. 그 결과 BD14 균주는 Pediococcus pentosaceus로 동정되었으며 나머지 6주는 Lactobacillus sp.로 동정되어 모두 안전성 있는 유산균임을 확인하였다. 여러 병원균에 가장 항균력이 큰 유산균은 L. pentosus K34이었으며, 이 유산균은 염산과 담즙산에 대한 내성에서도 가장 우수한 균주로 나타났다. 10종의 항생제에 대한 감수성을 조사한 결과 ciprofloxacin에 대하여 모든 균주가 내성을 보였고, BL 균주를 제외하고 모든 균주가 colistin, streptomycin에 대하여 내성을 보였다. 또한 BD14, BD16, K34 균주가 gentamicin에 대한 내성을 보였다.

• 한국식품저장유통학회지
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• 제5권3호
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• pp.286-291
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• 1998

4종류의 식중독세균(Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium)에 대하여 녹차 물추출물에 의한 항균작용을 조사하였다. 각 식중독세균을 tryptic soy broth(TSB)에 약 $10^{5}$CFU/ml 정도 되게 접종하여 35$^{\circ}C$에서 30시간 배양하였다. 세균의 배양중 대수증식기의 중기 혹은 말기에 녹차 물추출물을 0-2%(w/v)의 농도로 첨가하였을 때 증식억제 정도를 생균수 변화로서 비교하였다. 식중독세균의 증식은 첨가한 녹차 물추출물의 농도에 비례하여 억제되었으며 대수증식기 말기의 세균이 중기의 세균에 비하여 녹차 물추출물에 대한 내성이 컸다. Gram 양성균(L. monocytogenes, S. aureus)의 경우가 Gram 음성균(E. coli O157:H7, S. typhimurium)에 비하여 녹차 물추출물에 의한 억제효과는 월등히 컸다. 녹차 물추출물에 의한 증식억제 효과의 크기는 S. aureus, L. monocytogenes, E. coli O157:H7의 순이었으며 S. typhimurium에서 가장 강한 내성을 나타내었다.다.

• 한국환경보건학회지
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• 제42권1호
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• pp.34-40
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• 2016

Objectives: This study aims to examine the concentration, diversity, and antibiotic characteristics of penicillin G resistant enterobacteria present in pharmaceutical effluent. Methods: Water sampling was performed from a pharmaceutical company in Gyeonggi-do Province, Korea in March 2015. Water samples were plated in triplicate on tryptic soy agar plates with 32 mg/L of penicillin G. Penicillin G resistant enterobacteria were selected from the effluent and were subjected to 16S rRNA analysis for penicillin G resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Penicillin G resistant enterobacteria were present at 6.2% as to culturable heterotrophic bacteria. Identified penicillin G resistant enterobacteria exhibited resistance to more than 10 of the antibiotics studied. These resistant bacteria are gram negative and are closely related to pathogenic species. Conclusion: Multi-antibiotic resistant bacteria in the effluent suggest a need for disinfection and advanced oxidation processes for pharmaceutical effluents.