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

• 대한임상검사과학회지
• /
• 제46권2호
• /
• pp.64-67
• /
• 2014

Vancomycin-resistant Enterococci (VRE) are a leading cause of a nosocomial infection. While seven glycopeptide resistance genotypes have been found in Enterococci, vanA and vanB are the most common resistance genotypes. Aims of this study were to detect antibiotic susceptibilities of 23 Enterococcus spp, which broke out in a university hospital by the disk diffusion test, to investigate specific genes of vanA and vanB by conventional and real-time PCR. PCR for vanA and vanB was performed on 23 Enterococci, all 23 were positive for vanA type. This study reports the validation of a simple and rapid VRE detection method that can be easily incorporated into the daily routine of a clinical laboratory. Early detection of VRE strains, including those with susceptibility to Vancomycin, is of paramount clinical importance, as it allows a rapid initiation of strict infection control practices as well as a therapeutic guidance for a confirmed infection. The real-time PCR method is a rapid technique to detect vanA in Enterococci. It is simple and reliable for the rapid characterization of VRE.

• 한국수학교육학회지시리즈E:수학교육논문집
• /
• 제37권3호
• /
• pp.483-495
• /
• 2023

17세기 수학자 van Schooten(1657)은 저서 'Exercitationum mathematicarum'에서 포물선, 타원, 쌍곡선을 그리기 위한 연동장치를 제시하였다. van Schooten이 제시한 연동장치는 활동 중심 수학교육과 학교수학에서 수학사를 활용하기 위한 소재로 사용될 수 있다. 특히 학생들이 고등학교 교육과정에서 이차곡선을 조작하며 학습할 기회를 제공받지 못하고 있다는 점에서, van Schooten의 연동장치는 활동과 탐구 중심의 수학교육을 실현하는 데 도움을 줄 수 있다. 이를 위해 van Schooten의 연동장치를 동적 기하 환경에서 구현하는 방법을 제시하고, van Schooten의 연동장치를 이용하여 그린 도형의 자취가 포물선, 타원, 쌍곡선임을 증명하였다.

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

• 대한의생명과학회지
• /
• 제5권1호
• /
• pp.95-100
• /
• 1999

일반적으로 임상검사실에서 vancomycin resistant enterococci (VRE)를 검출하는 일은 어렵고, 시간이 많이 들며, 검체처리 비용도 많이 든다. 따라서 본 실험은 임상검체에서 분리된 세균으로부터 VRE를 신속하게 확인하고, 진단하기 위한 방법으로서 다중 중합효소 연쇄반응을 확립하였다. 본 실험에 사용된 primer는 장구균에 특이 한 유전자인 vanA, vanB, vanC-1, vanC-2/3 각각의 염기서열을 기초로 primer를 제작하고, 다중 중합효소 연쇄 반응을 실시하여 임상검체로부터 분리된 VRE 유전자의 type및 분포율을 조사하고자 하였다. 국내에서 분리된 75주의 장구균을 대상으로 다중 중합효소 연쇄반응을 실시한 결과 36주의 분리균주에서 vancomycin에 대해 높은 저항성을 보이는 vanA 유전자를 가진 것으로 나타났다. 그리고 18주에서는 vancomycin에 낮은 저항성을 내성을 보이는 vanC-1 또는 vanC-2/3 유전자를 보유한 것으로 나타났다. 따라서 본 실험에서 확립한 다중 중합효소 연쇄 반응 기법은 신속한 VRE 진단 방법으로 이용할 수 있을 것이다.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제39권2호
• /
• pp.151-166
• /
• 2000

The purpose of this study is to understand what two models of SOLO taxonomy and van Hiele theory suggest and find out what relation there is between the category system of the SOLO taxonomy and the thinking level of the van Hiele theory. The van Hiele theory describes in line of ranking level so that it may increase the teaching effects by putting together a class, which takes into consideration the students thoughts. The SOLO taxonomy focused on the response mode of the students rather than the thinking level or the developmental stage of them to pursuit the method that can describe the students understanding in depth quality-wise. Although the SOLO taxonomy and the van Hiele model seem to have different form and character from outside in terms of their goals, a closer examination reveals that the two stances have much in common and that the models are complementary. Although the van Hiele placed more focus on the thoughts, because the conclusion was based on the students responses, the van Hiele theory can be interpreted within the structure identified in the SOLO model. In this study, we have tried to understand how the response structure form the SOLO taxonomy and the thinking level of the van Hiele theory are related, based on the studies of Pegg and Davery1998). If you briefly look at them, there are following corresponding relation between the SOLO taxonomy and the van Hiele theory. a) The relational level(R) in iconic moe is van Hiele level 1. b) The multisturctural level(M$_2$) in the second cycle of concrete-symbolic mode is van Hiel level 2. c) The relation level(R$_2$) in the second cycle of concrete-symbolic mode is van Hiele level 3. d) The unistructural level(U$_2$) in the second cycle of formal mode is van Hiele level 4. e) The postformal mode is van Hiele levle 5. Though it would be difficult to conclude that these correspondences were perfectly done, if you look at their relation, you can see that the learning process of the students were not carried out uniformly. Therefore, by studying the students response structure, using the SOLO taxonomy, and identifying the learning cycle and understand the geometrical concept more in depth.

• Journal of Microbiology and Biotechnology
• /
• 제24권3호
• /
• pp.427-430
• /
• 2014

We developed a novel immunochromatographic assay (ICA) (EZ-Step VanA rapid kit; Dinona, Korea) for the detection of VanA ligase from vancomycin-resistant enterococci (VRE). Of eight monoclonal antibodies screened by ELISAs, the VanA ligase ICA constructed with 1H9 plus 3G11 showed the greatest reactivity. The detection limit of the kit was $6.3{\times}10^6$ CFU per test. Of 127 vancomycin-resistant microorganisms, 100 vanA VRE were positive in the VanA ligase ICA, and 27 non-vanA vancomycin-resistant isolates were negative. These results were consistent with those of the PCR analyses. Thus, our ICA is a reliable and easy-to-use immunological assay for detecting VanA-producing VRE in clinical laboratories.

• 대한임상검사과학회지
• /
• 제45권1호
• /
• pp.16-20
• /
• 2013

Outbreaks of vancomycin-resistant enterococci (VRE) are being reported more frequently in many countries. While seven glycopeptide resistance genotypes have been described in Enterococci, vanA and vanB are the most common resistance genotypes. The aim of this study was to detect antibiotic susceptibilities of 23 Enterococcus faecium strains, which caused an outbreak in a University hospital by a disk diffusion test to investigate the presence of the species specific gene, and the resistant genotypes, vanA and vanB by duplex PCR. PCR for vanA and vanB was performed on 23 enterococci. Twenty three were identified as E. faecium and were tested positive for the vanA genotype. This study will report on the validation of a simple and accurate VRE detection method that can be easily incorporated into the daily routine of a clinical laboratory. Early detection of VRE strains, including those with susceptibility to vancomycin, is of paramount clinical importance as it allows rapid initiation of strict infection control practices, as well as the therapeutic guidance for confirmed infections. The PCR method developed in the present study is simple and reliable for the rapid characterization of VRE.

• 대한수의학회지
• /
• 제43권1호
• /
• pp.103-112
• /
• 2003

A multiplex PCR assay, which allows simultaneous detection of vancomycin resistant genotypes and Enterococcus species-specific genes, was developed. Vancomycin resistant enterococci (VRE) from chickens and humans could be detected for vanA, vanB, vanC-1, vanC-2, $ddl_{E.faecium}$ and $ddl_{E.faecalis}$ by multiplex PCR. Eight isolates of VRE from humans (n=11) had $ddl_{E.faecium}$ and vanA, and 3 isolates of the VRE had $ddl_{E.faecium}$ and vanB. One isolate of VRE from chickens (n=6) had $ddl_{E.faecium}$ and vanA, and 5 isolates of the VRE had only vanA. E. faecium, E. faecalis, E. gallinarum and E. casseliflavus were also confirmed for the species-specific gene by multiplex PCR. This multiplex PCR could detect E. faecium, E. faecalis, E. gallinarum, E. casseliflavus, vanA, vanB, vanC-1 and vanC-2, simultaneously. The PCR assay established in the present study can be an alternative to time-consuming biochemical tests and antibiotic susceptibility tests of Enterococcus spp.

• 한국임상약학회지
• /
• 제9권1호
• /
• pp.1-14
• /
• 1999

Vancomycin-resistant Enterococci (VRE) have recently emerged in Korean hospitals, as well as in those of other countries. VRE have been partially attributed to the overuse and misuse of vancomycin. The mecbanisms of VRE resistance are related to VanA, VanB, and VanC. Both VanA and VanB produce abnormal ligase enzymes to form D-ala-D-lactate termini in E. faecium and E. faecalis, instead of D-ala-D-ala termini. Meanwhile, Van C produces D-ser-D-ala termini in E. gallinarum and E. casseliflavus. These abnormal termini have a low affinity to vancomycin. As a result, VRE avoid the activity of vancomycin by these mechanisms. Unfortunately, there is no approved therapy for the treatment of VRE. Thus, available but uncommonly prescribed antibiotics (due to their toxicity or unproven efficacy) may become possible options. They include chloramphenicol, novobiocin, fosfomycin, and bacitracin. The combination therapy of available agents may also be the other options. They include high doses of a penicillin- or ampicillin-aminoglycoside combination, high doses of an ampicillin/sulbactam and aminoglyoosidcs combination, an ampicillin and vancomycin combination, and a ciprofloxacin, aminoglycosides, and rifampin combination. With respect to the near future, many types of investigational agents will most likely expand their treatment options for VRE. Teicoplanin, a glycopeptide, can be used for VanB- and VanC-related VRE. LY333328, a new generation of glycopeptide, is effective in treating VanA as well as VanB and VanC. RP59500 (quinupristin/dalfopristin), a streptogramin, is effective in treating vancomycin-resistant E. faecium. New generation quinolones (especially clinatloxacin) are potential options for the treatment of VRE, even though they cannot work as effectively against VRE as they can against Staphylococci. Both glycylcyclines (a new generation of tetracyclines) and ketolides (a new generation of macrolides) show good activity against Enterococci, regardless of vancomycin susceptibility. Oxazolidinones (i. e. eperezolid and 1inezolid) and everninomicins (i. e. SCH27899) are new groups of antibiotics, which also demonstrate good activity against VRE. It is imperative that clinical pharmacists take the responsibility of investigating new treatment options for VRE in order to combat this growing problem throughout the world.