• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.567-570
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• 2012

In vitro activities of 13 antibiotics were assessed against 85 Brucella abortus isolates from naturally infected cattle in the Republic of Korea during 1998-2006, using broth microdilution test. Tetracyclines showed the most excellent activity against B. abortus, displaying MIC values of 0.5 ${\mu}g/ml$ or below. In particular, minocycline showed the lowest $MIC_{50/90}$ values (0.125/0.125 ${\mu}g/ml$) in this study. Among four fluoroquinolones tested, ciprofloxacin ($MIC_{50/90}$, 0.5/1 ${\mu}g/ml$) and norfloxacin ($MIC_{50/90}$, 8/8 ${\mu}g/ml$) had the most and the least activities, respectively. Gentamicin ($MIC_{50/90}$, 1/1 ${\mu}g/ml$) was more effective than streptomycin, erythromycin, rifampin, and chloramphenicol ($MIC_{50/90}$, 2/2 ${\mu}g/ml$).

• 한국수산과학회지
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• 제52권6호
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• pp.605-616
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• 2019

This study evaluated the abundance and antimicrobial resistance of Escherichia coli in oysters Crassostrea gigas and major inland pollution sources sampled in 2014-2015 from Jaranman-Saryangdo on the southern coast of Korea. The ranges of the geometric mean of E. coli concentrations in oysters and major inland pollution sources were <20-29.8 MPN/100 g and 7.5-137.2 MPN/100 g, respectively. We isolated 247 strains of E. coli (28 from oysters and 247 from major inland pollution sources) and examined the antimicrobial resistance patterns of all isolates. Isolates from both sources were highly resistant to rifampin (99.5-100%) and cephalothin (70.8-78.6%). The resistance rate was higher in E. coli isolated from oysters those from inland pollution sources. Multiple resistance against at least four antimicrobials was observed in 85.7% and 21.0% of the oyster and major inland pollution sources isolates, respectively.

• 대한수의학회지
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• 제47권4호
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• pp.395-398
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• 2007

A total of 114 Salmonella spp. (17.90%) were isolated from 637 fecal swab samples collected in October 2005 and they were from 25 (78.13%) of 32 farms investigated nation-widely in Korea. Salmonella spp. from age group of 30-, 60-, 90-, 120-day olds were 17.61%, 16.98%, 15.72%, and 21.25%, respectively. Nine serovars of Salmonella spp. were identified. The predominant serovars of isolates were S. Typhimurium (including var Copenhagen), S. Agona, S. Derby, and S. Heidelberg by turns. Almost isolates belonged to serogroup B (69.30%). All isolates were resistant to penicillin G and oxytetracycline, and this was considered due to be used as feed additive through the most of pig farms for decades. And also, frequent resistance observed for ampicillin, sulfamethoxazole-trimethoprim, and lincomycin-spectinomycin, which are commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved.

• 대한수의학회지
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• 제54권3호
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• pp.131-137
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• 2014

The purpose of present study was to investigate the antimicrobial resistance in Escherichia coli isolated from healthy animals in all provinces of the Republic of Korea. A total of 2,085 E. coli strains isolated from 11,336 fecal samples of healthy animals during 2010-2012 were examined for antimicrobial resistance. Comparison of average resistance rate through the years revealed that tetracycline (47.0% and 76.1%) and streptomycin resistance (42.6% and 64.6%) was most frequently observed in cattle and pigs, respectively. Whereas, in chicken isolates, resistance against nalidixic acid (90.9%) was highest among the antimicrobials tested. Percentage of E. coli that showed multidrug resistance (resistance against ${\geq}$ three subclasses of antimicrobial agents) was 17.6% (151/860) in cattle, 69.4% (506/729) in pigs, and 86.1% (427/496) in chickens. Overall, the rates of resistance are apparently different between animal species and, in particular, resistance was less prevalent in cattle than in pigs and chickens. In conclusion, this study showed higher prevalence of resistance in commensal E. coli strains to antimicrobial agents in Korean livestock and highlighted the urgent need for measures to regulate the abuse of antimicrobial agents.

• 한국축산식품학회지
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• 제37권4호
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• pp.502-510
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• 2017

This study investigated bacterial growth-inhibitory effect of 69 therapeutic herbal plants extracts on 9 bacterial strains using a disc diffusion assay. Especially, the antimicrobial activity of Psoraleae semen, which showed different activity on pathogenic Gram-positive and Gram-negative bacteria, was evaluated by MIC (minimal inhibition concentration) and biofilm formation assay. The effect of Psoraleae semen extract on bacterial cell membranes was examined by measurement of protein leakage (optical density at 280 nm) and scanning electron microscope (SEM). No clear zone was formed on discs containing Gram-negative bacteria, but Gram-positive bacteria exhibited clear zones. The MICs of Psoraleae semen extract were $8{\mu}g/mL$ for Streptococcus mutans, and $16{\mu}g/mL$ for Enterococci and Staphylococcus aureus. In addition, biofilm formation was inhibited at concentration $8-16{\mu}g/mL$. Protein leakage values and SEM images revealed that cell membranes of Gram-positive bacteria were impaired following exposure to the extract. Further, the extract inhibited the growth of Listeria monocytogenes in sausages. These results indicate that Psoraleae semen extract could be utilized as a natural antimicrobial agent against Gram-positive bacteria.

• 한국수산과학회지
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• 제38권6호
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• pp.365-371
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• 2005

The antimicrobial resistance patterns to the 10 antimicrobial agents of potential pathogenic vibrios isolated from seawater and a variety of farmed fishes, including oliver flounder (Payalichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagyus major) and sea bass (Lateolabyax japonicus), were investigated from May to October, 2004. A total of 314 strains of the genus vibrios were isolated from 126 collected samples, and the number of isolated strains of Vibrio payahaemolyticus and Vibrio alginolyticus were 194 and 120, respectively. Apparently $98.5\%$ of V. parahaemolyticus and $100\%$ of V. alginolyticus isolates demonstrated antimicrobial resistance against at least one antimicrobial agent. The resistance of V. parahaernolyticus isolates to ampicillin ($97.9\%$) was highest, followed by oxolinic acid ($26.8\%$), amikacin ($19.1\%$) and tetracycline and amoxicillin/clavulanic acid ($6.7\%$). V. alginolyticus isolates were resistant to ampicillin ($100\%$), solfamethoxazoleit,imethopenem ($25\%$), amikacln ($21.7\%$), amoxicillin/clavulanic acid ($15.8\%$), ciprofloxacin ($13.3\%$), and tetracycline and doxycycline ($11.7\%$). The rate of multiple antimicrobial resistance to at least four antimicrobials was higher in the V. alginolyticus isolates ($20.8\%$) than in the V. parahaemolyticus ($6.7\%$).

• Journal of Oral Medicine and Pain
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• 제43권1호
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• pp.1-7
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• 2018

Purpose: The purpose of the study was to investigate the influences of hyaluronic acid on the candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase (GO-PO) system at different concentrations of antimicrobial enzymes. Methods: Hyaluronic acid was used at a final concentration of 0.5 mg/mL. Hen egg-white lysozyme (HEWL) was used at concentrations ranging from 10 to $100{\mu}g/mL$. The peroxidase system included bovine lactoperoxidase (bLPO), potassium thiocyanate (KSCN, 1 mM), and hydrogen peroxide ($100{\mu}M$). The GO-PO system included bLPO, KSCN (1 mM), glucose oxidase (10 units/mL), and glucose ($30{\mu}g/mL$). The final concentration of bLPO in the peroxidase and GO-PO systems ranged from 12.5 to $100{\mu}g/mL$. Candida albicans strains ATCC 10231, 11006, and 18804 were utilized. Candidacidal activities of antimicrobials and the influence of hyaluronic acid on their candidacidal activities were determined based on colony forming units. Results: Candidacidal activities of the peroxidase and GO-PO systems increased with increasing concentrations of bLPO. This tendency was the same in the presence or absence of hyaluronic acid. Candidacidal activity of HEWL was not significantly concentration-dependent. Candidacidal activities of the GO-PO system were higher than those of the corresponding peroxidase system. Candidacidal activity was inhibited in the presence of hyaluronic acid in the following order: HEWL, the peroxidase system, and the GO-PO system. Conclusions: Hyaluronic acid inhibited the candidacidal activities of HEWL, the peroxidase system, and the GO-PO system. The GO-PO system exhibited better candidacidal activity than HEWL and the peroxidase system both in the presence and absence of hyaluronic acid.

• 한국식품저장유통학회지
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• 제7권1호
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• pp.12-18
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• 2000

경제적이면서 효과적인 항균성 필름의 생산방법으로서 corona 저려한 저밀도 폴리에틸렌 (LOPE) 필름에 천연항균성 물질을 코팅하는 방법을 개발하고, 이를 딸기의 포장에 적용하였다. 보다 안정한 항균제 코팅 필름의 생산을 위하여 결착제와 함께 코팅한 필름의 생산방법을 검토한 결과, polyamide수지용 과 항균생 물질을 함께 코팅함에 의하여 안정한 코팅을 행성할 수 있었다. 이의 항균성을 미생물 평판 배지 상에서 확인한 결과, 1% 자몽종자추출물로 코팅한 LDPE필름이 Escherichia coli, Staphylococcus aureus, Bacullus subtilis, Bacillus cereus, Leuconostoc mesenteroides, Micrococcus flavus, Saccharomyces cerevisiae 균주에 대해서 항균활성을 보여서 가장 우수하였다. 반면에 10% 대황추출물 코팅한 필름은 오직 M fiav$\mu$s에 대해서만 항균성올 보였고, 10% 대황추출물 코팅 필름은 실험에 사용된 10균주에 대해서 항균성을 나타내지 많았다. 결착제를 이용한 향균제 코팅필름은 딸기의 포장에 적용시 환경기체조절 포장에 작용하였을 때에 포장내에 $O_2$ 1.4-5.5%, $O_2$ 5.7~7.9%의 범위를 형성시켰으며, 비슷한 기체조성을 가진 일반 LDPE필름의 밀봉포장에 비해서 호기성 박테리아와 효모/곰팡이의 생육을 억제하였으나, 부패율 억제에는 뚜렷한 효과를 보이지는 않았다.

• 한국자원식물학회지
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• 제24권2호
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• pp.200-207
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• 2011

본 연구는 구실잣밤나무를 식품 저장성이나 안전성을 향상하기 위한 식품 보존제로서의 개발 가능성을 알아보고자 하였다. 구실잣밤나무의 잎을 에탄올로 추출하고 헥산, 디클로로메탄, 에틸아세테이트, 부탄올로 순차적으로 용매분획하였다. 먼저, 항산화활성으로 DPPH 소거활성, superoxide radical 소거 활성 그리고 xanthine oxidase 억제 활성을 측정하였다. 그 결과, 에틸아세테이트 분획물에서 농도 의존적으로 가장 높은 항산화 활성을 나타내었다. 항균활성은 에탄올 추출물과 용매분획물을 농도별로 조사한 결과 다른 분획물에 비해 Bacillus sublitis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis 그리고 Salmonella typhimurium에서 에틸아세테이트 분획물에 높은 활성을 띠었다. 이상의 결과를 볼때, 구실잣밤나무 잎 추출물은 식품 보존제의 개발에 적합할 수 있다고 사료 된다.

• 한국수산과학회지
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• 제49권6호
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• pp.800-806
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• 2016

In total, 151 Escherichia coli isolates from Ruditapes philippinarum in Gomso Bay were analyzed for their susceptibility to 18 different antimicrobial agents and for genes associated with virulence. For virulence genes, each strain of the isolates was positive for the enterotoxigenic E. coli (ETEC)-specific heat-stable toxin (estA), enteroinvasive E. coli (EIEC)-specific invasion-associated locus (iaa) gene and enteropathogenic E. coli (EPEC)-specific attaching and effacing (eae) gene. According to a disk diffusion susceptibility test, resistance to ampicillin was most prevalent (23.2%), followed by resistance to amoxicillin (22.5%), ticarcillin (20.5%), tetracycline (18.5%), nalidixic acid (12.6%), ciprofloxacin (10.6%), streptomycin (9.9%), and chloramphenicol (6.6%). More than 35.8% of the isolates were resistant to at least one antimicrobial agent, and 19.9% were resistant to four or more classes of antimicrobials; these were consequently defined as multidrug resistant. Minimum inhibitory concentration (MIC) ranges for the antimicrobial resistance of the 15 different antimicrobial agents of 54 E. coli strains were confirmed by varying the concentrations from $32-2,048{\mu}g/mL$. Overall, these results not only provide novel insights into the necessity for seawater and R. philippinarum sanitation in Gomso Bay but they also help to reduce the risk of contamination by antimicrobial-resistant bacteria.