• Bulletin of the Korean Chemical Society
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• 제17권10호
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• pp.909-918
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• 1996

Syntheses of carbapenam skeletons were achieved from 1,3-propanediol through 1,3-dipolar cycloaddition. 3-(Tetrahydropyran-2-yloxy)-(10) and 3-(t-butyldimethylsilyloxy) propanal (13) were obtained from 1,3-propanediol. 3-Hydroxypropanals (10, 13, 14) were reacted with N-hydroxyglycine esters to give C-(2-hydroxyethyl)-N-alkoxycarbonylmethylnitrones (15a-15d). 1,3-Dipolar cycloaddition of the nitrones with methyl acrylate or ethyl crotonate gave 3-(2-hydroxyethyl)isoxazolidines (16a-16b, 17a-17b, 18, 19a-19b). 3-(2-Hydroxyethyl)isoxazolidines (17a, 17c, 19a, 19b) were converted to 3-(2-iodoethyl)isoxazolidines (21a-21d) or 3-phenylthiocarbonylmethylisoxazolidines (25a-25d) which were cyclized to give 2-oxa-1-azabicyclo[3.3.0]octanedicarboxylates (22a-22d, 26a-26d). 2-Oxa-1-azabicyclo[3.3.0]octane-4,8-dicarboxylates (22c-22d, 26c-26d) were transformed to 6-(l-hydroxyethyl)carbapenam-3-carboxylates (30a-30b, 31a-31b).

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.411-414
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• 1989

A new sensitive fluorimetric method for the determination of N-methylcarbamates, a class of well known insecticides, based on the derivatization with 7-chloro-4-nitrosobenz-2-oxa-1,3-diazole (NBD-Cl) has been developed. Unreacted NBD-Cl was eluted ahead of derivatized carbamates from C-18 bonded column. An argon ion laser was used as an excitation source of chromatographic eluents and its fluorescence signal was monitored with optical multichannel analyzer. The detection limits of various carbamates were about 100 pg range and the working curves were linear to $10^4-10^5$ nanogram ranges.

• 대한임상검사과학회지
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• 제42권2호
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• pp.71-80
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• 2010

Pseudomonas aeruginosa are important nosocomial pathogens. Their resistance to carbapenem is increasing and causing concerns in Korea. An increasing prevalence of carbapenem resistance mediated by acquired carbapenemase is being reported. Over a 10 month-period from July 2007 to April 2008, 32 strains of imipenem-nonsusceptible P. auruginosa were isolated from Kangwon National University Hospital. To determine the prevalence and genotypes of the carbapenemase-producing clinical isolates, the antibiotic susceptibility was determined by Microscan Walkaway 96 SI System and the carbapenem activity was detected by the modified Hodge test and the imipenem-EDTA-SMA double-disk synergy test. The metallo-${\beta}$-lactamase gene and OXA-type ${\beta}$-lactamase gene reported in Korea were detected by PCR. As for the result of PCR, 30 isolates of P. aeruginosa were found to have $bla_{IMP-1}$-like and 1 isolate was found to have $bla_{IMP-1}$-like and $bla_{IMP-2}$. No clinical isolates were found to have $bla_{SIM-1}$, $bla_{OXA-23}$-like and $bla_{OXA-24}$-like. Random amplified polymorphic DNA (RAPD)-PCR and dendrogram for genetical similarity to band patterns of each clinical isolates were examined. P. aeruginosa were grouped into 7 clusters of up to 50% of similarity index. In the P. aeruginosa group, PS3 was resistant to the most antibiotics, PS1 was susceptible to the most antibiotics. PS7 was resistant to aztreonam unlike other groups. This is the first report of prevalence of carbapenemase in Chuncheon.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1481-1489
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• 2016

The emergence and dissemination of carbapenemase-producing Acinetobacter baumannii isolates have been reported worldwide, and A. baumannii isolates harboring bla_OXA-23 are often resistant to various antimicrobial agents. Antimicrobial resistance can be particularly strong for biofilm-forming A. baumannii isolates. We investigated the genetic basis for carbapenem resistance and biofilm-forming ability of multidrug-resistant (MDR) clinical isolates. Ninety-two MDR A. baumannii isolates were collected from one university hospital located in the Chungcheong area of Korea over a 5-year period. Multiplex PCR and DNA sequencing were performed to characterize carbapenemase and bap genes. Clonal characteristics were analyzed using REP-PCR. In addition, imaging and quantification of biofilms were performed using a crystal violet assay. All 92 MDR A. baumannii isolates involved in our study contained the bla_OXA-23 and bap genes. The average absorbance of biomass in Bap-producing strains was much greater than that in non-Bap-producing strains. In our study, only three REP-PCR types were found, and the isolates showing type A or type B were found more than 60 times among unique patients during the 5 years of surveillance. These results suggest that the isolates have persisted and colonized for 5 years, and biofilm formation ability has been responsible for their persistence and colonization.

• Journal of Microbiology
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• 제44권4호
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• pp.423-431
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• 2006

Among 53 Acinetobacter baumannii isolates collected in 2004, nine imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Korea. Nine carbapenemase-producing isolates were further investigated in order to determine the mechanisms underlying resistance. These isolates were then analyzed via antibiotic susceptibility testing, microbiological tests of carbapenemase activity, pI determination, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. One outbreak involved seven cases of infection by A. baumannii producing OXA-23 ${\beta}-lactamase$, and was found to have been caused by a single ERIC-PCR clone. During the study period, the other outbreak involved two cases of infection by A. baumannii producing IMP-1 ${\beta}-lactamase$. The two clones, one from each of the outbreaks, were characterized via a modified cloverleaf synergy test and an EDTA-disk synergy test. The isoelectric focusing of the crude bacterial extracts detected nitrocefin-positive bands with pI values of 6.65 (OXA-23) and 9.0 (IMP-1). The PCR amplification and characterization of the amplicons via direct sequencing showed that the clonal isolates harbored $bla_{IMP-1}$ or $bla_{oxA-23}$ determinants. The two clones were characterized by a multidrug resistance phenotype that remained unaltered throughout the outbreak. This resistance encompassed penicillins, extended-spectrum cephalosporins, carbapenems, monobactams, and aminoglycosides. These results appear to show that the imipenem resistance observed among nine Korean A. baumannii isolates could be attributed to the spread of an IMP-lor OXA-23-producing clone. Our microbiological test of carbapenemase activity is a simple method for the screening of clinical isolates producing class D carbapenemase and/or class B $metallo-{\beta}-lactamase$, in order both to determine their clinical impact and to prevent further spread.

• 미생물학회지
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• 제46권3호
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• pp.303-307
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• 2010

임상분리 균주인 A. baumannii 1625는 imipenem (carbapenem 계열)을 포함한 대부분의 ${\beta}$-lactam계열의 항생제들과 kanamycin, gentamicin, tobramycin 및 제 3세대와 4세대 cephalosporin 계열의 항생제들에 광범위한 내성을 나타내었고, 한국에서는 드문 IMP-1형 metallo-${\beta}$-lactamase (MBL)를 생성하는 균주임이 확인되었다. A. baumannii 1625는 약 2.5 kb 크기의 class 1 integron을 갖고 있었으며, 이 integron내에 aminoglycoside계열 내성 유전자인 accA4, carbapenem 계열 내성 유전자인 $bla_{IMP-1}$, 광범위한 ${\beta}$-lactam 내성 유전자인 $bla_{OXA-2}$ 유전자 cassette들이 차례대로 위치해 있음을 확인하였는데, 이것은 IMP-1형과 OXA-2형 ${\beta}$-lactamase의 유전자를 같은 integron내에 동시에 갖는 새로운 배열 및 구조로서 이전에 국내에서 보고된 바 없는 것이다. 이 2.5 kb 크기의 integron을 항생제 내성이 없는 E. coli에 형질전환 시켰을 때, imipenem, ampicillin, piperacillin, cefazolin, cefoperazone, aztreonam 등의 항생제들에 대하여 8배 이상 증가된 내성정도를 보였다. 이는 A. baumannii 1625의 integron이 다제내성을 부여하는 기능을 하고 있음을 보여준다.

• 대한의생명과학회지
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• 제18권1호
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• pp.79-82
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• 2012

Acinetobacter infections are of great concern in clinical settings because of multi-drug resistance (MDR) and high mortality of the infected patients. The MDR Acinetobacter baumannii has emerged as a significant infectious agent in hospitals worldwide. The purpose of this study was to determine for molecular characterization of MDR A. baumannii clinical isolates obtained from the Wonju Christian Hospital in Gangwon province of Korea. A total of seventy nonduplicate A. baumannii isolates were collected from the Wonju Christian Hospital in Korea from March to April in 2011. All of the MDR A. baumannii isolates were encoded by $bla_{OXA-23-like}$ gene and all isolates with the $bla_{OXA-23-like}$ gene had the upstream element ISAba1 to promote increased gene expression and subsequent resistance to carbapenem. 16S rRNA methylase gene (armA) was detected in 44 clinical isolates which were resistant to amikacin, and phosphotransferase genes encoding aac(3)-Ia and aac(6')-Ib were the most prevalent. A combination of 16S rRNA methylase and aminoglycoside-modifying enzyme genes (armA, aac(3)-Ia, aac(6')-Ib, and aph(3')-Ia) were found in 31 isolates. The sequencing results for the quinolone resistance-determining region (QRDR) of gyrA and parC revealed the presence of Ser (TCA) 83 Leu (TTA) and Ser (TCG) 80 Leu (TTG) substitutions in the respective enzymes for all MDR. Molecular typing for MDR A. baumannii could be helpful in confirming the identification of a common source or cross-contamination. This is an important step in enabling epidemiological tracing of these strains.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.247-248
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• 2005

• 대한화학회지
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• 제51권3호
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• pp.232-239
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• 2007

1,1'-Bis(dimethylsilyl)ferrocene과 다양한 aldehydes를 소량의 Ni(PEt3)4 촉매하에서 반응시켰을 경우 hydrosilylation 반응에 의한 비고리형의 monohydrosilylation 된 생성물이 얻어졌다. 그러나 촉매를 Ni(PEt3)4 대신에 (C2H4)Pt(PPh3)를 사용한 경우에는 고리형의 double silylation 된 6각 고리 생성물이 얻어졌다. 특히 Pt 촉매하에서 4-cyanobenzaldehyde silylation 반응은 double silylation 된 5,6-ferrocenylene-1,1,4,4-tetramethyl-2-oxa-2-cyanophenyl-1,4-disilacyclohexane의 결정을 얻었다.

• 한국동물위생학회지
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• 제30권4호
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• pp.505-510
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• 2007

This study was conducted to detect ${\beta}$-lactam antibiotic-resistant genes in the 400 E coli isolates from porcine fecal samples in Korea by a DNA chip. The DNA chip contains the specific probe DNAs of the ${\beta}$-lactam antibiotic-resistant genes that had been labeled with a mixture of primer set designed to amplify specific genes (PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY and AmpC) using a multiplex polymerase chain reaction (PCR). Of 400 isolates 339 contained at least one ${\beta}$-lactamases gene. Resistance to ${\beta}$-lactamases was mediated mainly by AmpC (n = 339, 100%), and followed by TEM (n = 200, 59.0%), CMY (n = 101, 29.8%), PSE (n = 30, 8.9%) and both OXA and SHV genes (n = 20, 5.9%), while the FOX, MEN and OXY genes were not detected. The other sixty-one did not contain any ${\beta}$-lactamase genes even though they were resistant to antimicrobial drugs. In conclusion, the DNA chip system can be used as a rapid and reliable method for detecting of ${\beta}$-lactamases genes, which will help veterinarians select the antibiotics for monitoring and treating of animal diseases.