• Archives of Pharmacal Research
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• 제26권8호
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• pp.638-643
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• 2003

Raw milk samples, and cow and chicken intestines were tested to isolate vancomycin-resistant, gram-positive bacteria. From these samples, we isolated seven vancomycin-resistant Streptococcus equinus, two vancomycin-resistant viridans Streptococcus and two vancomycin-resistant Enterococcus faecium. The MICs of several antibiotics, including vancomycin, against these strains were tested. Seven isolates of S. equinus showed high level resistance to vancomycin and teicoplanin (＞100 $\mu$ g/mL). The cell wall thickness of these strains was compared with that of the sensitive strain by TEM and no differences were obserbed between these strains. We compared the strains of vancomycin-resistant Streptococcus equinus using PCR with Microbial Uniprimer Kit. We concluded that it is necessary to combine other methods in order to cluster and identify all isolates of S. equinus.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.143-147
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• 2005

The non-pathogenic, non-glycopeptide-producing actinomycete Streptomyces coelicolor carries a cluster of seven genes (vanSRJKHAX) that confers inducible, high-level resistance to vancomycin. The van genes are organised into four transcription units, vanRS, vanJ, vanK and vanHAX, and these transcripts are induced by vancomycin in a vanR-dependent manner. vanHAX are orthologuous to genes found in vancomycin resistant enterococci that encode enzymes predicted to reprogramme peptidoglycan biosynthesis such that cell wall precursors terminate in D-Ala-D-Lac, rather than D-Ala-D-Ala. vanR and vanS encode a two-component signal transduction system that mediates transcriptional induction of the seven van genes. vanJ and vanK are novel genes that have no counterpart in previously characterised vancomycin-resistance clusters from pathogens. VanK is essential for vancomycin resistance in S. coelicolor and it is required for adding Gly branch to stem peptides terminating D-Ala-D-Lac. Because VanK can recognise D-Lac-containing precursors but the constitutively expressed femX enzyme, encoded elsewhere on the chromosome, cannot recognize D-Lac-containing precursors as a substrate, vancomycin-induced expression of VanHAX in a vanK mutant is lethal. Further, femX null mutants are viable in the presence of glycopeptide antibiotics but die in their absence. Bioassay using vanJp-neo fusion reporter system also showed that all identified inducers for van genes expression were glycopeptide antibiotics, but teicoplanin, a membrane-anchored glycopeptide, failed to act as an inducer.

• 한국식품과학회지
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• 제38권2호
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• pp.313-316
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• 2006

장내 상주균이며 probiotics로 활용되고 있는 Bifidobacterium에 대한 항생제 내성분포를 분석하였다. 분석된 93개의 Bifidobacterium이 chlolurnphenicol, rifampicin, erythromycin에 대해서는 감수성을 갖고 있었고, aminoglycoside계 항생제, nalidixic acid와 vancomycin에 내성을 갖는 것으로 나타났다. 그리고 vancomycin의 MIC가 $100\;{\mu}g/mL$ 이상인 균이 전체 균주 중 34%를 차지했다. Tetracycline, erythromycin, penicillin에 대한 내성은 매우 다양하게 나타났다. ${\beta}-lactam$계 항생제인 penicillin G와 cephalothin은 10년보다 더 내성이 높아졌음을 알 수 있었고, ampicillin, amoxicillin, tetracycline은 항생제 농도가 점차 증가하고 있는 것으로 보인다. 인체유래 분리균과 유산균식품 분리균의 항생제 내성은 대부분 비슷한 특성을 보였으나 유산균식품 분리 균주중 vancomycin의 MIC가 $100\;{\mu}g/mL$ 이상인 균주가 약 20%가 되는 것으로 나타났다. 따라서 새로운 probiotics를 개발하기 위해서는 이러한 항생제 내성 특성을 분석하고 항생제 내성 위해성에 대한 검증이 필요한 것으로 보인다.

• 대한의생명과학회지
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• 제19권3호
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• pp.280-283
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• 2013

Leuconostoc spp. is intrinsically resistant against vancomycin and rarely causes the infection in immunocompromised patients. In this report, we describe a fatal case of Leuconostoc lactis bacteremia in a patient with biliary tract stent insertion to resolve the biliary tract obstruction by multiple pseudocysts in the pancreatic head region. Leuconostic lactis isolated from the blood of the patients was confirmed by 16S rRNA sequencing and this isolate was susceptible against most antibiotics, including levofloxacin, penicillin, erythromycin and cefotaxime except vancomycin. The septic shock and multi-organ failure was abruptly progressed due to delayed use of adequate antibiotic. Using vancomycin as the empirical antibiotics in a bacteremic patient by Gram positive cocci, the treatment failures by the isolates with intrinsic resistance against vancomycin have to be considered. In addition, the prompt and accurate identification of Leuconostoc spp. are very important to select the adequate antibiotics.

• Journal of Microbiology and Biotechnology
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• 제20권3호
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• pp.637-642
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• 2010

We investigated the prevalence and the molecular characteristics of vancomycin-intermediate Staphylococcus aureus (VISA) among methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical samples at tertiary or general hospitals participating in a nationwide surveillance program for VISA and vancomycin-resistant Staphylococcus aureus (VRSA) in Korea during an 8-week period in each year from 2001 to 2006. Of 41,639 MRSAs isolated, 37,856 were screened and 169 grew on brain heart infusion agar supplemented with 4 ${\mu}g/ml$ vancomycin. A vancomycin MIC of 4 ${\mu}g/ml$ was confirmed for 33 VISA isolates of the 169 isolates. Eighteen of the 33 isolates were classified as hetero-VISA (hVISA) by the population analysis profile (PAP) method. All VISA isolates were susceptible to linezolid, tigecycline, and quinupristin-dalfopristin. Most VISA isolates (MIC 4 ${\mu}g/ml$) showed a PFGE C pattern with sec, seg, and sei enterotoxin genes, including ST5-SCCmec type II, or a PFGE A pattern with sea, including ST239-SCCmec type III.

• 대한의생명과학회지
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• 제26권3호
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• pp.149-156
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• 2020

We developed a simple and rapid method for detecting vancomycin resistance genes, such as vanA and vanB, using loop-mediated isothermal amplification (LAMP). To identify not only vancomycin resistance genes, but also the genus Enterococcus, primers were designed for vanA, vanB, and 16S rRNA. Screening for vancomycin susceptibility in Enterococcus was performed using Etest (bioMérieux Inc). The results of the LAMP assay were compared to those of real-time RT-PCR. The optimal conditions for the LAMP assay were 65℃ for 60 min. The detection limits of the LAMP assay for vanA, and vanB were 2 × 10² copies/reaction. Compared to RT-PCR, the sensitivities and specificities of LAMP for 16S rRNA, vanA, and vanB were 100/100%, 100/100%, and 100/100%, respectively. The vanA genotype-vanB phenotype accounted for 57.5% (46/80) of the vancomycin-resistant Enterococci samples collected from 2016 to 2019. In conclusion, the LAMP assay developed in this study showed high sensitivity and specificity for vancomycin-resistant genes. Moreover, due to the simplicity and rapidity of the LAMP assay, its use can be very useful in clinical microbiology laboratories.

• Food Science and Biotechnology
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• 제15권4호
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• pp.511-515
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• 2006

Antibiotic resistance of foodborne pathogens adapted to garlic (Allium sativum Linn.) was determined in order to understand the relationship between antibiotic resistance and garlic. The Gram (-) strains of Escherichia coli and Salmonella typhimurium and the Gram (+) strains of Bacillus cereus and Staphylococcus aureus were subcultured consecutively in a garlic broth, and the surviving colonies on the agar were selected as the adapted strains. Minimal inhibitory concentrations (MIC) for 15 antibiotics on the adapted strains were determined on Muller-Hinton Infusion agar. Adaptation to 1.3%(v/v) garlic juice increased MIC for vancomycin, aminoglycoside, and erythromycin on B. cereus, and for ampicillin and erythromycin on E. coli O157:H7. MIC of aminoglycosides, chloramphenicol, and vancomycin on the adapted S. aureus increased. The adapted S. typhimurium was more resistant to penicillin and vancomycin than the non-treated strain. The adapted S. typhimurium and S. aureus lost their antibiotic resistance in non-garlic stress conditions. However, the adapted B. cereus was still resistant to erythromycin and vancomycin, and the adapted E. coli was also resistant to erythromycin. Antibacterial garlic might increase the antibiotic resistance of E. coli, B. cereus, S. aureus, and S. typhimurium and this resistance can continue even without the stress of garlic. Therefore, garlic as a food seasoning could influence the resistance of such pathogens to these antibiotics temporarily or permanently.

• 대한수의학회지
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• 제39권2호
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• pp.343-352
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• 1999

Vancomycin resistant enterococci (VRE) have emerged as an important nosocomial pathogen. Since 1989 the Center for Disease Control, United States, has reported a rapid increase in the incidence of enterococcal bacteremia and endocarditis infection by VRE. It was suggested that the use of avoparcin was associated with the appearance of VRE in animal husbandry. To date, several detection methods have been used based on conventional methods of culture and gene detection. However, these methods have some limitations such as time-consuming, laborious and additional differential needs. Therefore, In this study a multiplex PCR method was established to detect and differentiate resistance types of enterococci which specifically amplify the four van genes encoding vancomycin resistance elements. Using the method, we investigated the incidence rates and types of VRE from farms using or not using avoparcin. A total of 1091 animal fecal samples were collected from 70 pig and 32 poultry farms. A total of 425 of enterococci were isolated from samples. Of the 425 isolates, 11 of the them showed a pattern of high-level vancomycin resistance (MIC : $64{\sim}256{\mu}g/ml$) which was associated with the presence of the vanA or vanB gene. Fifty-seven isolates showed a pattern of low-level vancomycin resistance (MIC : $3{\sim}8{\mu}g/ml$) associated with the vanC-1 or vanC-2 gene. Interestingly, all isolates with high-level vancomycin resistance were from farms that have never used avoparcin. Moreover, the high-level VRE isolation rate in Korea (2.58%) was much lower than that of other countries (50% in England, 7% in Belgium) where avoparcin have been used. In conclusion, the multiplex PCR method established in this study could be applied for detection of VRE.

• 한국식품영양과학회지
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• 제41권5호
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• pp.714-720
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• 2012

콩 발효식품인 청국장과 된장에서 분리한 $Enterococcus$의 항생제 내성을 평가하고자 31개의 청국장과 17개의 된장으로부터 $Enterococcus$를 분리, 동정한 후 항생제 내성특성을 분석하였다. 모든 청국장 시료에서 119균주, 된장시료에서 4균주, 총 123개의 $Enterococcus$를 분리하였고 가장 많이 분리된 종은 청국장에서는 $E.$ $faecium$ 69균주, $E.$ $faecalis$ 20균주 등이며 된장시료에서 분리한 4균주는 모두 $E.$ $faecium$으로 동정되었다. 총 123개의 $Enterococcus$는 ampicillin, chloramphenicol, penicillin, tetracycline에 내성이 낮게 나타났다. 그리고 erythromycin, ripampin, streptomycin 등에게는 내성이 높은 것으로부터 민감성이 있는 것까지 다양하게 분포하였다. 청국장에서 분리된 $Enterococcus$의 vancomycin MiC 범위는 0.25~8 ${\mu}g/mL$로 나타났으며, MiC 8 ${\mu}g/mL$ 정도의 낮은 내성균 17균주가 $E.$ $faecalis$, $E.$ $faecium$, $E.$ $gallinarum$, $E.$ $casselifalvus$ 등에 고르게 분포되어 있음을 알 수가 있었다. 모든 분리균주에서 고농도 vancomycin 내성유전자인 $van$A, $van$B는 검출되지 않았다. 본 연구의 결과 $Enterococcus$는 자연환경에 널리 분포하고 있는 만큼 가공식품에는 항생제 내성균주와 vancomycin-resistant $Enterococcus$가 존재할 수 있으나 이들 청국장, 된장 등의 콩 발효식품 $Enterococcus$에는 주요 항생제에 내성정도가 높지 않아 항생제 안전성이 있는 것으로 보인다.

• 대한의생명과학회지
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• 제6권3호
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• pp.201-208
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• 2000

Vancomycin은 세포벽의 합성을 억제하여 세균에 대한 항균효과를 나타내는 glycopeptide 계 항생물질로서 그람양성세균으로 인한 감염치료에 광범위하게 사용되며, 특히 methicillin 내성 포도상구균의 선택적 치료제로 쓰이고 있다. 그러나 최근 임상검체에서도 중등도의 내성을 가지는 포도상구균 (Mu50: MIC 8 $\mu\textrm{g}$/ml)이 나타나기 시작하였고 여러 가지 여건상 국내에서도 내성균주가 분리될 가능성이 높다고 사료되어 임상검체 중 methcillin 내성 포도상구균을 대상으로 vancomycin 감수성 및 내성빈도 조사를 실시하고 이에 따른 내성기전을 알아보고자 하였다. 본 실험 결과 107주 (株)의 methicillin 내성균주 중 23.3%가 vancomycin에 대하여 내성을 보였으며 vancomycin 내성을 나타내는 표준균주인 Mu50과 Mu3의 중간 정도의 내성빈도를 보였다. 중합효소 연쇄반응을 통해 장구균의 vancomycin 내성에 관여하는 vanA, vanB, vanC1, vanC2, vanH 특이 유전자는 증폭되지 않았다. SDS-PAGE를 실시하여 81 kDa, 58 kDa, 33 kDa, 28 kDa 등의 주요 단백 분획을 확인하였고, Mu50에서 45 kDa의 특징적인 단백 분획을 관찰하였다. LDH enzyme assay에서는 한 개의 검체가 Mu50과 함께 높은 LDH 활성을 보였다.