• 한국미생물·생명공학회지
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• 제47권3호
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• pp.459-464
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• 2019

This study aimed to identify and characterize the antimicrobial activity of prodigiosin produced by Serratia sp. $PDGS^{120915}$ isolated from stream water in Busan, Korea; the identification was performed using phonological, biochemical, and molecular techniques, including 16S rRNA sequence analysis. Prodigiosin from the bacterial culture was purified by high-performance liquid chromatography (HPLC), and its antimicrobial activity and minimum inhibitory concentrations (MICs) were evaluated against 10 intestinal pathogenic gram-positive and negative bacteria. The results revealed that the isolated prodigiosin exhibited high antimicrobial activity against Listeria monocytogenes, Bacillus cereus, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, and Vibrio parahaemolyticus; further, the isolated prodigiosin showed minimum inhibitory concentrations (MICs) between $3{\mu}g/ml$ and 30 mg/ml, but they were not active against Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumonia, and Escherichia coli. In conclusion, prodigiosin isolated from Serratia sp. $PDGS^{120915}$ showed high antimicrobial activity against intestinal pathogenic bacteria and has potential applications in the development of new antimicrobial agents.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.479-491
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• 2015

Lactobacillus species have been shown to enhance intestinal epithelial barrier function, modulate host immune responses, and suppress the growth of pathogenic bacteria, yeasts, molds, and viruses. Thus, lactobacilli have been used as probiotics for treating various diseases, including intestinal disorders, and as biological preservatives in the food and agricultural industries. However, the molecular mechanisms used by lactobacilli to suppress pathogenic bacterial infections have been poorly characterized. We previously isolated Lactobacillus plantarum JSA22 from buckwheat sokseongjang, a traditional Korean fermented soybean food, which possessed high enzymatic, fibrinolytic, and broad-spectrum antimicrobial activity against foodborne pathogens. In this study, we investigated the effects of L. plantarum JSA22 on the growth of S. Typhimurium and S. Typhimurium-induced cytotoxicity by stimulating the host immune response in intestinal epithelial cells. The results showed that coincubation of S. Typhimurium and L. plantarum JSA22 with intestinal epithelial cells suppressed S. Typhimurium infection, S. Typhimurium-induced NF-κB activation, and IL-8 production, and lowered the phosphorylation of both Akt and p38. These data indicated that L. plantarum JSA22 has probiotic properties, and can inhibit S. Typhimurium infection of intestinal epithelial cells. Our findings can be used to develop therapeutic and prophylactic agents against pathogenic bacteria.

• 한국식품과학회지
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• 제34권3호
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• pp.480-486
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• 2002

김치 발효가 병원성 장내세균의 생육에 미치는 여향을 조사하기 위하여 배추 및 갓 김치를 제조할 때에 6종의 병원성 장내세균을 접종하여 발효 중의 이들의 변화를 측정하고, 또 김치의 주된 재료에서 검출되는 대장균과 이들 원료로 담근 김치 중의 대장균군 균수의 변화를 측정하였다. 주된 김치 재료 중 대장균군이 가장 많이 검출된 것은 생강과 대파였으며 그 다음이 배추, 고춧가루, 마늘의 순이었다. 김치 중의 대장균군 또는 시험 병원균은 모두 발효의 진행에 의한 pH의 저하에 따라 감소하고 사멸되었다. 대장균군은 배추김치에서 pH 3.9 이하에서 검출되지 않았으며 Clostridium perfringens ATCC 13124, Listeria monocytogenes ATCC 19111, Salmonella typhimurium KCTC 1625, Staphylococcus aureus KCTC 1621, Vibrio parahamolyticus ATCC 27519, 및 Escherichia coli O157 : H7 ATCC 43894는 배추김치에서 pH 4.1, 3.7, 3.8, 3.8, 3.7, 및 3.7 이하에서 각각 검출되지 않았고 갓김치에서는 pH 4.5, 4.0, 4.2, 4.2, 4.2 및 4.1 이하에서 각각 검출되지 않았다. 또 갓 즙액 및 allyl isothiocyanate는 병원균에 대해서 뚜렷한 생육저해효과를 나타내었으며 젖산균에 대한 효과는 미약하였다. 이들 결과로부터 김치 발효는 김치의 안전성을 높이게 되면 갓의 병원균에 대한 뚜렷한 생육저해효과는 주로 갓 중에 함유된 자극성 성분인 allyl isothiocyanate 의 항균작용에 의한 것으로 추정되었다.

• 미생물학회지
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• 제11권4호
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• pp.175-180
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• 1973

This study was attempted to see more clear relationships among the enterobacteria, especially between the intestinal normal flora and pathogenic bacteria. It has been known that some intestinal normal flora produce the bactrial metabolites that are harmful to other enteric bacteria. One of the metabolites is known as colicin, the protein fraction, which possesses certain degree of inhibitory effect against other bacterial growth fraction, whih possesses certain degree of inhibitory effect against other bacterial growth. As a preliminary study for a colicin purification, the antagonistic effect of E, coli to groups of Salmonella and Shigella has been studied by means of in vitro quantitative culture method. 1. E.coli showed definite inhibitory effects aganist both Salmonella and Shigella groups in the mixture of two organisms. 2. The inhibitory effects of E.coli in the E.coli-Salmonella and the E.coli-Shigella mixture occurred from 4 hours incubation following the inoculation. 3. Even the complete inhibition of pathogenic enteric bacterial growth was noticed in the E.coli-Salmonella mixture at overnight incubation. 4. Among the diluted mixtures, 1:100, 1:1,000, and 1:10,000, survival rate of pathogenic enteric bacteria in the mixtures with E.coli showed least affected at the 1:1,000 dilution. 5. It was found that the antagonistic effect aganist groups of Salmonella-shigella was depending upon the groups of the genera.

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.355-364
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• 2022

From independent swab samples of the cloaca of indigenous gamecocks (CIG), anus of healthy baby goats (AHG), and vagina of goats (VG) originating from Phitsanulok, Thailand, a total of 263 isolates of lactic acid bacteria (LAB) were collected. Only three isolates, designated C707, G502, and V202, isolated from CIG, AHG, and VG, respectively, exhibited an excellent inhibitory zone diameter against foodborne pathogenic bacteria when evaluated by agar spot test. Isolates C707 and G502 were identified as Enterococcus faecium, whereas V202 was identified as Pediococcus acidilactici, based on 16S rRNA sequence analysis. When foodborne pathogenic bacteria were co-cultured with chosen LAB in mixed BHI-MRS broth at 39℃, their growth was suppressed. These LAB were found to be capable of surviving in simulated stomach conditions. Only the isolate G502 was able to survive in the conditions of simulated intestinal juice. This research suggests that selected LAB could be used as a food/feed supplement to reduce foodborne pathogenic bacteria and improve the safety of animal-based food or feed.

• Animal Bioscience
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• 제35권8호
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• pp.1109-1120
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• 2022

Antibiotics used to be supplemented to animal feeds as growth promoter and as an effective strategy to reduce the burden of pathogenic bacteria present in the gastro-intestinal tract. However, in-feed antibiotics also kill bacteria that may be beneficial to the animal. Secondly, unrestricted use of antibiotics enhanced the antibiotic resistance in pathogenic bacteria. To overcome above problems, scientists are taking a great deal of measures to develop alternatives of antibiotics. There is convincing evidence that probiotics could replace in-feed antibiotics in poultry production. Because they have beneficial effects on growth performance, meat quality, bone health and eggshell quality in poultry. Better immune responses, healthier intestinal microflora and morphology which help the birds to resist against disease attack were also identified with the supplementation of probiotics. Probiotics establish cross-feeding between different bacterial strains of gut ecosystem and reduce the blood cholesterol level via bile salt hydrolase activity. The action mode of probiotics was also updated according to recently published literatures, i.e antimicrobial substances generation or toxin reduction. This comprehensive review of probiotics is aimed to highlight the beneficial effects of probiotics as a potential alternative strategy to replace the antibiotics in poultry.

• 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.

• 농업과학연구
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• 제44권2호
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• pp.181-187
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• 2017

The use of practical management factors to maximize pig health improvement cannot guarantee freedom from diseases. Moreover, because of health safety concerns, the use of antibiotics has been restricted in livestock, including pigs. Therefore, the swine industry has been looking for various alternatives to antibiotics to improve pig's health and performance. Clay is a dietary factor generally accepted for improving pig health. It is a naturally occurring material and is primarily composed of fine-grained minerals. It has a specific structure with polar attraction. Because of this structure, clay has the ability to lose or gain water reversibly. In addition, clay has beneficial physiological activities. First, clay has anti-diarrheic and antibacterial effects by penetrating the cell wall of bacteria or inhibiting their metabolism. Second, it can protect the intestinal tract by absorbing toxins, bacteria, or even viruses. When added to the diet, clay has also been known to bind some mycotoxins, which are toxic secondary metabolites produced by fungi, namely in cereal grains. Those beneficial effects of clay can improve pigs' health and performance by reducing pathogenic bacteria, especially pathogenic Escherichia coli, in the intestinal tract. Therefore, it is suggested that clay has a remarkable potential as an antibiotics alternative.

• 한국미생물·생명공학회지
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• 제42권3호
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• pp.211-218
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• 2014

본 연구에서는 동물유래 시료들로부터 양돈 사료첨가용 유산균을 개발하기 위하여 enterotoxigenic E. coli, Salmonella Typhimurium, Clostridium perfringens 등 양돈산업에서 심각한 문제를 일으키는 인수공통 병원성 세균들과 Clostridium jejuni, Listeria monocytogenes, Staphylococcus aureus와 같은 식중독균을 강하게 저해하는 Bifidobacterium 유산균을 분리하고자 하였다. 이를 위하여 소의 반추위 내용물, 닭 창자 내용물, 돼지 분변 등의 시료들로부터 총 65주의 혐기성미생물을 분리하였다. 이 중에서 항병원세균활성이 가장 높은 4주를 선별하였는데, 이들은 16S rDNA 염기서열 분석방법에 의하여 3주의 B. boum과 1주의 B. thermophilum으로 동정되었다. 특히 B. thermophilum는 분리주들 중에서 가장 높은 돼지 장 상피세포에 대한 부착성을 보였고, 여러 인수공통병원세균들과 식중독균들에 대한 높은 항균력, 산과 담즙내성을 보여 양돈용 생균제 후보균주로서 우수한 특성을 나타내었다.

• 약학회지
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• 제48권1호
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• pp.70-74
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• 2004

Bacillus polyfermenticus SCD which is commonly called as Bisroot (equation omitted) has been appropriately used for the treatment of long-term intestinal disorder's. This strain strongly inhibited against methicillin resistance Staphylococcus aureus (MRSA) and various pathogenic microorganisms. Effects of B. polyfermentius SCD administration on death rates and egg-laying rates in two groups of hens were investigated. This strain decreased the death rates of two groups by 16.26％ and 11.72％, respectively. Also this strain increased the egg-laying rates of those 2.74％ and 2.66％, respectively Clinical tests of B. polyfermenticus SCD administration to healthy adults showed not adverse effects but decreased glyceride concentration from 154.52 mg/dl to 135.41 mg/dl after two week administrations.