• 한국환경농학회지
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• 제42권3호
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• pp.169-176
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• 2023

The emergence and spread of antibiotic-resistant bacteria have been increasing with anthropogenic contamination. Understanding the prevalence and distribution of these resistant bacteria in environments is crucial for effectively managing anthropogenic pollutants. Lake Gyeongpo in the Gangwon Province of South Korea is known for its diverse ecological features and human interactions. The lake is exposed to pollutants from nonpoint sources, including urban areas, agricultural practices, and recreational activities, which can introduce antibiotics and foster antibiotic resistance in bacteria. The present study investigates Lake Gyeongpo as a potential reservoir for antibiotic-resistant bacteria in a natural ecosystem. A total of 203 bacterial isolates were collected from six sampling locations in Lake Gyeongpo during May, July, and November 2022. Most isolates were taxonomically identified as Pseudoalteromonas, Bacillus, Shewanella, and Vibrio spp.; their abundance showed a spatiotemporal distribution. An antibiotic susceptibility test was conducted on 75 isolates using the disk diffusion method with six drugs according to the CLSI guideline; 42 isolates were resistant to one or more antibiotics. Among these, 15 isolates were identified as multidrug resistant bacteria. This finding suggests the potential anthropogenic impact on Lake Gyeongpo and provides valuable insights into the dissemination of antibiotic resistance caused by anthropogenic pollutants.

• 대한환경공학회지
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• 제33권7호
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• pp.492-500
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• 2011

육상양식장에서 항생제에 대한 내성을 가진 균을 분리하여 다양한 항생제에 대한 내성특성을 확인하고, 전자빔의 조사에 따른 내성균의 항생제 내성 특성변화와 살균효능에 관한 연구를 수행하였다. 메기, 송어, 뱀장어, 미꾸라지양식장의 배출수에서 분리된 균주 중 Aeromonas sp., Citrobacter sp., Bacillus sp., Marinobacter sp., Pantoea sp., Pseudomonas sp., Enterobacter sp.가 다제내성균으로 확인되었다. 양식장 배출수에서 분리한 균주 중 한가지의 항생제 내성을 가지고 있는 균은 41.7%이며, 2가지 이상의 항생제 내성을 가지고 있는 균은 58.3%로 나타났다. Quantitative Structure Analysis Relationship (QSAR) model에 의한 평가는 실험값과 매우 유사하여 독성 평가의 간접적인 지표로 이용될 수 있음을 알 수 있었다. 항생제 내성균에 대해 전자빔을 조사한 결과 1 kGy 이내의 선량에서 살균효율이 99.9%로 강한 살균력을 확인할 수 있었다.

• Natural Product Sciences
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• 제13권4호
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• pp.342-346
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• 2007

The antimicrobial activity of the essential oil from Pelargonium graveolens and its effects when it was combined with current antibiotics against antibiotic-resistant strains of Streptococcus pneumoniae were evaluated. The minimal inhibitory concentrations (MICs) of the essential oil fraction and the main components of this plant were determined for two antibiotic-susceptible and two antibiotic-resistant strains of S. pneumoniae using broth microdilution tests. The combined effects of the oil with erythromycin, norfloxacin, or oxacillin were evaluated using a checkerboard microtitre assay. The combination of the oil fraction of P. graveolens, or its main component, together with the antibiotics tested significantly lowered the MICs of the antibiotics against all of the tested strains with fraction inhibiting concentration indices (FICs) ranging from 0.16 to 1.50. In particular, the activity of norfloxacin against all of the tested strains of S. pneumoniae was enhanced significantly by combination with citronellol. In conclusion, the combination of P. graveolens oil with antibiotics could be used to reduce the effective dose of antibiotic and to modulate the resistance of S. pneumoniae strains.

• 멤브레인
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• 제34권2호
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• pp.96-104
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• 2024

항생제는 과도한 사용으로 인해 폐수뿐만 아니라 다양한 수원에서 발견되는 새로운 오염 물질 중 하나입니다. 수중 항생제 오염 물질을 처리하기 위한 고도 산화 공정, 생물학적 처리 등 다양한 기술이 있습니다. 이 두 가지 공정은 비효율적이며, 부산물의 생성은 이 공정을 더욱 복잡하게 만듭니다. 오염 물질을 제거하기 위한 또 다른 대안으로 막 기술이 있습니다. 항생제와 내성 유전자의 제거를 개선하기 위해 막 생물 반응기는 NaClO와 탄소 물질로 변형됩니다. 풍부한 반응성 종의 생성은 항생제의 내성 유전자에 대해 활성입니다.

• 한국어병학회지
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• 제5권1호
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• pp.37-48
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• 1992

항생제란 어떤 미생물의 생성물질로서 다른 미생물의 증식을 억제하거나 살균작용을 나타내는 것을 의미한다. 현재까지 알려진 4000여종의 항생제중, 수산용으로는 약 20여종이 사용되고 있다. 이러한 항생제의 분류는 화학적 구조와 부수되는 기능에 의하는 것이 일반적이며 그 효과는 적용되는 병원성균의 종류와 어류가 처해있는 환경에 따라 대단히 영향을 받는다. 그러므로 항생제의 종류와 적용방법은 정확한 질병에 대한 원인 규명이 있은 후 결정되어져야 할 것이다. 무절제하게 사용된 항생제는 자연적으로 발생하여 존재하고 있는 내성균을 선택적으로 증식 가능케 한다. 이미 일본의 수많은 양어장에서 내성균 출현의 보고가 있었고, 많은 종류의 내성균은 R plasmid를 가지고 있다는 것도 밝혀졌다. 우리나라의 양어장에서도 내성균 출현과 R plasmid에 의한 내성균 확산은 곧 문제가 될 수 있는 가능성이 크므로 전반적인 역학조사가 있어야 할 것이다. 상용항생제의 어류에 대한 약동력학, 잔존량, 임상적용 실험등에 대한 연구는 상당히 되어 있어 적절한 이들 항생제의 사용이 가능하지만, 현재까지 대부분의 수산용 항생제에 대해서는 연구해야 될 부분이 아직 많이 남아 있다. 그러므로 어류질병 치료와 항생제의 정확한 사용을 위해서는 양식사업을 하고 있는 현장과 진단을 할 수 있는 실험실의 긴밀한 협조관계가 무엇보다 중요하다 할 것이다.

• 대한의생명과학회지
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• 제13권1호
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• pp.47-53
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• 2007

Due to wide abuse of antibiotics both in human and livestock use, the advent and spread of multidrug resistant (MDR) pathogens becomes a serious health problem all over the world. Since the development of new antibiotics is at a standstill in pharmaceutical industry, the choice of therapeutic antibiotics is getting narrower. In this study, in an effort to search new antibiotics, the antimicrobial activity of Paenibacillus DY1 isolated from Korean soil was characterized on its growth inhibition spectrum against various health threatening MDR strains, with its stability and chemical structure. Extracellular culture filtrate of Paenibacillus DY1 effectively inhibits the growth of all the tested MDR enteropathogenic Eshcherichia coli, enterohemolytic E. coli, and enterotoxigenic E. coli strains, at a similar level to that on the nonresistant control E. coli strains. It showed significant growth inhibition effect against the causative agents of class one legal communicable disease, MDR Salmonella typhi, MDR Salmonella paratyphi A, food poisoning bacteria, MDR Salmonella typhimurium, and other MDR Salmonella spp. The growth of all of 10 different MDR Shigella spp. strains and 6 different Vibrio spp. strains tested was also inhibited. The antimicrobial activity of Paenibacillus DY1 was well preserved after heat treatment, and was also stable in both alkaline and acidic environment. The antimicrobial activity was partially purified with Diaion HP20 column and TLC. By NMR study, the putative structure of the activity was postulated as an alkane having hydroxyl groups.

• 대한수의학회지
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• 제37권4호
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• pp.773-777
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• 1997

A retrospective study of 132 cases of natural Escherichia coli infection in preweaning piglets with diarrhea submitted to the Department of Veterinary Pathology in Seoul National University from 1995 to 1996 was performed to determine the biochemical characteristics and antibiotics susceptibility. Most field isolates were lysine decarboxylase-positive (99.2%), phenylalanine decarboxylase-negative (100%), and fermented sorbitol (91.7%). Antibiotic susceptibilities will be determined by agar diffusion method. A large percentage of isolates were resistant to many antibiotics in common usage. Most isolates were susceptible to colistin (98.8%), gentamycin (64.3%), amikacin (100%), and ceftiour sodium (64.2%), whereas most isolates were notably resistant to ampicillin (86.9%), neomycin (66.7%), streptomycin (84.5%), tetracycline (98.8%), penicillin (98.8%), and amoxacillin (58.3%).

• 미생물학회지
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• 제16권4호
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• pp.161-169
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• 1978

Escherichiae-like organisms were isolated from rectal specimens of 56 children who were either in preschool age or in elementary school. The isolated strains were subjected to tests to screen enteropathogens producing heat-labile enterotoxin and susceptibility test to various antibiotics by disc diffusion method on agar plates. Production of heat-labile enterotoxin by the strains was assyed in the sensitive and reproducible cultured adrenal tumor cell system. The assay was sterodogenesis of the cell in the presence of heat-labile enterotoxin. Among 56 strains, gave positive reaction in the test of toxin production. This meant that about 10% of the children population objected to the study harbored the toxigenic strain of enteropathogenes. Some of these toxigenic strains were resistant to the antibiotics employed in the test. This study suggested that considerable population in Korea may harbor entertoxigenic E. coli as a part of intestinal normal flora. The toxigenic strains which are resistant to antibiotics may bring issue of public health in the future.

• 한국수산과학회지
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• 제42권1호
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• pp.20-25
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• 2009

Thirty-eight Vibrio spp. were isolated from the sea waters harvested from the 22 stations located on the west coast of the Korean peninsula in September 2006. The isolates consisted of V. parahaemolyticus (n=21), V. alginolyticus (n= 16) and V. cholerae non-01 (n=1), among which 35 isolates displayed resistance against two of the tested antibiotics. Among the 38 isolates, 18 isolates exhibited multi-drug resistance against more than four 4 antibiotics. In particular, minimum inhibitory concentration $(MIC)_{50}$ and $MIC_{90}$ of ampicillin-resistant isolates were as high as $2,048{\mu}g{\cdot}mL^{-1}$ and $4,096{\mu}g{\cdot}mL^{-1}$ respectively. $\beta$-lactamase production was examined to analyze the ampicillin-resistance. Some Vibrio spp. isolates produced $\beta$-lactamase, however antibiotics resistance pattern and $\beta$-lactamase production were not clearly related to each other. A genetic relationship between resistance and gene expression was confirmed in the ampicillin-resistant isolates.

• 동의생리병리학회지
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• 제26권6호
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.