• 한국축산식품학회지
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• 제41권2호
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• pp.261-273
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• 2021

Leuconostoc mesenteroides H40 (H40) was isolated from kimchi, and its probiotic properties and neuroprotective effect was evaluated in oxidatively stressed SH-SY5Y cells. H40 was stable in artificial gastric conditions and can be attached in HT-29 cells. In addition, H40 did not produce β-glucuronidase and showed resistant to several antibiotics. The conditioned medium (CM) was made using HT-29 cells refined with heat-killed probiotics (Probiotics-CM) and heated yogurts (Y-CM) to investigate the neuroprotective effect. Treatment with H40-CM not only increased cell viability but also significantly improved brain derived neurotropic factor (BDNF) expression and reduced the Bax/Bcl-2 ratio in oxidatively stress-induced SH-SY5Y cells. Besides, probiotic Y-CM significantly increased BDNF mRNA expression and decreased Bax/Bcl-2 ratio. The physicochemical properties of probiotic yogurt with H40 was not significantly different from the control yogurt. The viable cell counts of lactic acid bacteria in control and probiotic yogurt with H40 was 8.66 Log CFU/mL and 8.96 Log CFU/mL, respectively. Therefore, these results indicate that H40 can be used as prophylactic functional dairy food having neuroprotective effects.

• 한국수산과학회지
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• 제54권6호
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• pp.918-926
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• 2021

We isolated 28 Vibrio vulnificus strains from seawater and fisheries and investigated the positive rate of eight virulence genes. Additionally, we evaluated the susceptibility of these strains to 25 antimicrobials. The positive rates of fur, vvhA, tcp, rtxA, vcgC, viuB, vvp, and acfA were 100, 92.9, 92.9, 67.9, 64.3, 25.0, 14.3, and 7.1%, respectively. A disk diffusion susceptibility test revealed that, all the investigated strains had the highest resistance to amoxicillin and oxacillin, followed by that to streptomycin (96.4%), cefoxitin (92.9%), clindamycin (82.1%), amikacin (67.9%), vancomycin (46.4%), nalidixic acid (7.1%), penicillin G (7.1%), and ampicillin (3.6%). Moreover, they were susceptible to 10 other antimicrobials, including cefotaxime, chloramphenicol, erythromycin, gentamicin, and rifampicin. Notably, amoxicillin, oxacillin, and streptomycin had average minimum inhibitory concentrations of 132.6, 603.4, and 23.1 ㎍/mL against V. vulnificus, respectively. These observations provide new insights regarding the necessity for sanitation of commercial fisheries and can potentially, help reduce the risk posed by fisheries contaminated with bacteria resistant to antimicrobials.

• Journal of Species Research
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• 제10권4호
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• pp.321-335
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• 2021

In 2020, a total of 12 bacterial strains were isolated from soil after a comprehensive investigation of indigenous prokaryotic species in Korea. It was determined that each strain belonged to independent and predefined bacterial species, with high 16S rRNA gene sequence similarity (>98.7%) and formation of a robust phylogenetic clade with the closest species. This study identified four families in the phylum Actinobacteria, two families in the phylum Proteobacteria, one family in the phylum Bacteroidetes one family in the phylum Firmicutes; and four species in the family Nocardiaceae, two species in the family Nocardioidaceae, one species in the family Cellulomonadaceae, one species in the family Hymenobacter, one species in the family Methylobacteriaceae, one species in the family Microbacteriaceae, one species in the family Bacillaceae and one species in the family Sphingomonadaceae. There is no official report of these 12 species in Korea, so they are described as unreported bacterial species in Korea in this study. Gram reaction, basic biochemical characteristics, colony, and cell morphology are included in the species description section.

• Biomolecules & Therapeutics
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• 제31권2호
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• pp.141-147
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• 2023

Antibiotic resistance has emerged as a global threat to modern healthcare systems and has nullified many commonly used antibiotics. β-Lactam antibiotics are among the most successful and occupy approximately two-thirds of the prescription antibiotic market. They inhibit the synthesis of the peptidoglycan layer in the bacterial cell wall by mimicking the D-Ala-D-Ala in the pentapeptide crosslinking neighboring glycan chains. To date, various β-lactam antibiotics have been developed to increase the spectrum of activity and evade drug resistance. This review emphasizes the three-dimensional structural characteristics of β-lactam antibiotics regarding the overall scaffold, working mechanism, chemical diversity, and hydrolysis mechanism by β-lactamases. The structural insight into various β-lactams will provide an in-depth understanding of the antibacterial efficacy and susceptibility to drug resistance in multidrug-resistant bacteria and help to develop better β-lactam antibiotics and inhibitors.

• Journal of Animal Science and Technology
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• 제66권2호
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• pp.266-278
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• 2024

Antibiotic resistance (AR) is a complex, multifaceted global health issue that poses a serious threat to livestock, humans, and the surrounding environment. It entails several elements and numerous potential transmission routes and vehicles that contribute to its development and spread, making it a challenging issue to address. AR is regarded as an One Health issue, as it has been found that livestock, human, and environmental components, all three domains are interconnected, opening up channels for transmission of antibiotic resistant bacteria (ARB). AR has turned out to be a critical problem mainly because of the overuse and misuse of antibiotics, with the anticipation of 10 million annual AR-associated deaths by 2050. The fact that infectious diseases induced by ARB are no longer treatable with antibiotics foreshadows an uncertain future in the context of health care. Hence, the One Health approach should be emphasized to reduce the impact of AR on livestock, humans, and the environment, ensuring the longevity of the efficacy of both current and prospective antibiotics.

• International Journal of Advanced Culture Technology
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• 제12권1호
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• pp.190-201
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• 2024

This study examined the effect of the distance Infection Control Education Program (ICEP), developed based on the ADDIE model, on infection control knowledge, attitude, and performance among care workers in long-term care facilities nationwide. The program, developed based on the ADDIE model, was applied to 173 care workers directly responsible for nursing care of elderly residents in lomg-term care facilities. The distance ICEP for care workers was conducted through the website and lasted 30 minutes for each of the eight topics. To determine the effectiveness of the education, infection control knowledge, attitude, performance, and satisfaction were surveyed before and four weeks after the program. Differences in infection control knowledge, attitude, and performance before and after the distance ICEP were assessed by a t-test. A significant difference was observed in knowledge and infection control performance after the distance ICEP was administered to care workers. In the sub-domains of infection control performance, overall understanding of infection, regular infection control education, infection control by special pathogen (multidrug-resistant bacteria, tuberculosis, tick-borne infectious diseases), and detailed infection control education by infection site (pressure ulcers and urinary tract infections) were significantly improved. Infection control knowledge and performance improved through the distance ICEP applied to care workers. Satisfaction also displayed high scores on most items and indicated that it was helpful for infection control in facilities, confirming the effectiveness of infection control education. Based on the survey of care workers nationwide, the infection education program can be effectively used for care workers in the future.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.681-688
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• 2024

The accurate and rapid detection of methicillin-resistance of Staphylococcus aureus (SA) holds significant clinical importance. However, the methicillin-resistance detection strategies commonly require complicated cell lysis and gene extraction. Herein, we devised a novel colorimetric approach for the sensitive and accurate identification of methicillin-resistance of SA by combining allosteric probe-based target recognition with self-primer elongation-based target recycling. The PBP2a aptamer in the allosteric probe successfully identified the target MRSA, leading to the initiation of self-primer elongation based-cascade signal amplification. The peroxidase-like hemin/G-quadruplex undergo an isothermal autonomous process that effectively catalyzes the oxidation of ABTS2- and produces a distinct blue color, enabling the visual identification of MRSA at low concentrations. The method offers a shorter duration for bacteria cultivation compared to traditional susceptibility testing methods, as well as simplified manual procedures for gene analysis. The overall amplification time for this test is 60 min, and it has a detection limit of 3 CFU/ml. In addition, the approach has exceptional selectivity and reproducibility, demonstrating commendable performance when tested with real samples. Due to its advantages, this colorimetric assay exhibits considerable potential for integration into a sensor kit, thereby offering a viable and convenient alternative for the prompt and on-site detection of MRSA in patients with skin and soft tissue infections.

• Asian-Australasian Journal of Animal Sciences
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• 제30권9호
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• pp.1340-1349
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• 2017

Objective: This study aimed to evaluate the microbiological and cellular milk profile for the diagnosis of subclinical mastitis in female buffaloes and to assess risk factors for predisposition of the disease. Methods: Analyses were carried out by standard plate count (SPC), identification of species and antibiotic resistance, somatic cell count (SCC), electrical electrical conductivity of milk (ECM), and lactoferrin content in milk. Teat cups were swabbed to evaluate risk factors, observing hyperkeratosis, milking vacuum pressure and cleanliness of the site. Hence, 30 female buffaloes were randomly selected (15 from a group in early lactation and 15 in late lactation). Results: The most common bacteria in the microbiological examination were Staphylococcus spp., Streptococcus spp. and Corynebacterium sp. In the antibiotic sensitivity test, 10 (58.82%) of the 17 antibiotics tested were sensitive to all isolates, and resistant bacteria were Streptococcus uberis, Streptococcus dysgalactiae, Streptococcus haemolyticus, and Escherichia coli. It was observed that positive samples in the microbiological examination showed total bacterial count between $9.10{\times}10^3$ to $6.94{\times}10^6$ colony forming units/mL, SCC between 42,000 to 4,320,000 cells/mL and ECM ranging from 1.85 to 7.40 mS/cm. It was also found that the teat cups had high microbial counts indicating poor hygiene, and even faults in the cleanliness of the animals' waiting room were observed. It is concluded that values of SCC above 537,000 cells/mL and ECM above 3.0 mS/mL are indications of mammary gland infection for this herd; however, the association of these values with a microbiological analysis is necessary to more accurately evaluate the health status of mammary glands with subclinical mastitis. Conclusion: Through phenotypic characterization of bacteria involved in the samples, the genera Staphylococcus spp., Streptococcus spp., and Corynebacterimum bovis were the most prevalent in this study. Faults in environment and equipment hygienization are factors that are directly associated with mastitis.

• 한국미생물·생명공학회지
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• 제37권2호
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• pp.110-117
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• 2009

독도에 자생하고 있는 야생 가지과 식물근권세균들의 특성을 밝히기 위해 까마중을 채집하였다. 까마중 근권으로부터 총 44종의 포자형성세균 혹은 질소고정세균을 분리하였다. 이 균주들은 16S rDNA 염기서열을 이용하여 부분 동정하였다. PGPR로써의 특성을 밝히기 위해 옥신 생산능, 인 가용능, 그리고 Siderophore 형성능을 측정하였다. 식물 생장호르몬인 옥신을 형성하는 균주는 19종, 난분해성 인을 분해할 수 있는 균주는 8종, 식물병원균을 억제하는 siderophore를 형성할 수 있는 균주는 13종으로 확인되었다. 우리나라에서 널리 재배되고 있는 가지과식물인 담배와 고추에 직접 적용하여, 식물의 생장 촉진 효과 및 식물 전신유도저항성 효과를 확인하였다. 특히 KUDC1009는 식물의 생장 촉진 효과 그리고 식물병원균에 대한 저항성을 증가시키는 등 다기능의 능력을 가지는 것을 확인할 수 있었다. 독도의 근권세균들은 다양한 스트레스 환경하에서 야생 까마중이 생존하는데 많은 도움을 주는 것을 추측 할 수 있었다.

• 한국응용곤충학회지
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• 제16권4호
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• pp.229-234
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• 1977

벼 흰빛잎마름균을 이용하여 Streptomycin 계약제인 Agrepto에 대한 내성형질의 선발효과를 조사하여 다음과 같은 결과를 얻었다. 1) 사용된 약제 Agrepto는 $105^{\circ}C$에서 20분간의 온도처리에서 약제의 안정성을 보였다. 2) 서로 다른 지역균주인 75-6 및 75-9 묘주는 선발영제농도 10ug/ml 및 100ug/ml에서 상이한 내성력을 나타내는 내성균이 선발되었다. 3) 저농도인 10ug/ml 및 100ug/ml의 선발농도에서도 10,000ug/ml에서 생장이 가능한 내성균이 선발될 수 있었다. 4) 전세대 100ug/ml에서 선발하고 재차 3,000ug/ml에서 선발된 선발균주는 처리농도 100ug/ml에서 무처리와 동일한 생장량을 보였다. 5) 자연집단의 균주 75-9를 100ug/ml에서 선발한 이들 분리균주는 내성 정도에 있어서 500ug/ml 이하, 500-1,000ug/ml 및 1,000-3,000ug/ml의 내성을 나타내는 몇단계의 내성력 정도가 상이한 균들이 분포하고 있었다.