• Journal of Life Science
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• v.20 no.5
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• pp.676-682
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• 2010

This study focused on typing of the extended-spectrum $\beta$-lactamase (ESBL) produced in organisms isolated from a natural environment, rather than a clinical setting. Samples were collected from drain water issuing from a sewage plant in Kwanganri (Busan, Korea). Following double disk synergy testing, 29 strains were selected as potential ESBL positive strains. Of these, 15 strains were transconjugants of the sodium azide resistant recipient strain Escherichia coli J53 and analyzed biochemically including indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase and sugar-fermentation tests. The tests classified the 15 strains as Klebsiella pneumoniae (n=13) and Escherichia coli (n=2). The type of ESBL from each strain was deduced by isoelectric focusing point analysis and DNA sequencing. The results indicated that the types of ESBL were SHV-12 (n=4) and SHV-12/TEM-1 (n=9) from K. pneumoniae and TEM-1 (n=2) from E. coli strains.

• Macromolecular Research
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• v.14 no.2
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• pp.194-198
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• 2006

Polystyrene, PS, particles of 450 nm diameter and poly(styrene-co-styrene sulfonate), PSS, particles of 140-160 nm diameter were prepared by emulsifier-free emulsion polymerization. The surfaces of the PS and PSS particles were coated with Ag nanoparticles for the application of antimicrobial agents by reduction of Ag ions using ${\gamma}$-irradiation. The Ag-PS and Ag-PSS were characterized by High-Resolution Transmittance Electron Microscopy (HR-TEM), Field-Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-ray Spectroscopy (EDXS). The HR-TEM and EDXS data showed that the Ag nanoparticles were loaded on the surface of the PS and PSS particles, respectively. The antimicrobial efficiency of the Ag-PS and Ag-PSS particles (0.4 g) with ca. 100 ppm Ag, which was coated onto yam (KS K 0905-1996 rule), was tested against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 after 100 washing cycles (KS K 0432-1999 rule). The antimicrobial efficiency of the Ag-PS particles against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 was 99.9% after 100 cycles washing., confirming that the Ag-PS particles can be used as antimicrobial agents.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1620-1628
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• 2016

In this study, we investigated colistin resistance mechanisms associated with the regulation of the pbgP operon in Klebsiella pneumoniae, using four isogenic pairs of colistin-susceptible strains and their colistin-resistant derivatives and two colistin-resistant clinical isolates. Amino acid sequence alterations of PhoPQ, PmrAB, and MgrB were investigated, and mRNA expression levels of phoQ, pmrB, pmrD, and pbgP were measured using quantitative real-time PCR. The phoQ and pmrB genes were deleted from two colistin-resistant derivatives, 134R and 063R. We found that phoQ, pmrD, and pbgP were significantly upregulated in all colistin-resistant derivatives. However, pmrB was significantly upregulated in only two colistin-resistant derivatives and one clinical strain. pmrB was not overexpressed in the other strains. The minimum inhibitory concentration of colistin was drastically lower in both phoQ- and pmrB-deleted mutants from a colistin-resistant derivative (134R) that was overexpressing phoQ and pmrB. However, colistin susceptibility was restored only in a phoQ-deleted mutant from a colistin-resistant derivative (063R) without overexpression of pmrB. In conclusion, two different regulations of the pbgP operon may associate with the development of colistinresisant K. pneumoniae.

• Clinical and Experimental Pediatrics
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• v.56 no.9
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• pp.407-410
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• 2013

Klebsiella pneumoniae has emerged as a leading pathogen that causes pyogenic liver abscesses (PLAs) in Korea. K. pneumoniae liver abscess (KLA) is potentially life threatening, and the diagnosis is difficult. In developed countries, PLA is rarely observed in children and is frequently associated with disorders of granulocyte function and previous abdominal infection. We observed a case of KLA in a healthy 12-year-old boy. To our knowledge, this is the first reported case of KLA in an immunocompetent child without an underlying disease in Korea. The patient was treated with percutaneous catheter drainage and antibiotics. The catheter was placed in the intrahepatic abscess for 3 weeks and parenteral antibiotics (ceftriaxone and amikacin) were administered for 4 weeks, followed by oral antibiotics (cefixime) for 2 weeks. We reported this case to raise awareness of KLA in immunocompetent children among physicians, and to review the diagnosis, risk factors, potential complications, and appropriate treatment of KLA.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.885-896
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• 2013

2,3-Butanediol (2,3-BDO) has immense industrial applications. Recently, microbial fermentation has emerged as an alternative way to produce this industrially important chemical. Although 2,3-BDO is produced by several microorganisms, the Klebsiella genera has an excellent production compared with other 2,3-BDO-producing microorganisms. In order to produce 2,3-BDO on a large scale, the challenges of removing pathogenic factors from Klebsiella pneumoniae need to be addressed. K. pneumoniae produces a number of virulence factors that contribute to its pathogenesis, including lipopolysaccharides, capsules, fimbrial adhesins, etc. Removal of these pathogenic factors from 2,3-BDO-producing Klebsiella strains will result in avirulent strains for the safe, economic, and efficient production of 2,3-BDO. In this review, we summarize the current trends in 2,3-BDO production using K. pneumoniae and insights into the removal of its virulence factors for industrial applications.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.270-276
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• 1999

Background: Extended-spectrum ${\beta}$-lactamases(ESBL) are enzymes that confer resistance to oxyimino-${\beta}$-lactams as well as to penicillins and cephalosporins. Strains of Klebsiella pneumoniae and Escherichia coli that produce ESBL have been increasingly prevalent in many countries. The purpose of this study was to investigate the ESBL production rate of K. pneumoniae and E. coli at the in Yeungnam University Medical Center. Materials and Methods: Thirty-one isolates of K pneumoniae and twenty-five isolates of E. coli were examined for ESBL by double disk synergy test, using 20/$10{\mu}g$ ticarcillin/clavulanic acid and $30{\mu}g$ oxyimino-${\beta}$-lactam(ceftazidime, ceftaxime, ceftriaxone and aztreonam) disks. Results: Fifty-two percent of K. pneumoniae and sixteen percent of E. coli isolates revealed double disk synergism. Majority of ESBL-producing strains(fifty-five percent) were isolated from patients in the intensive care unit. Conclusion: ESBL production of K. pneumoniae and E. coli were also common at the Yeungnam University Medical Center and pose a serious problem for antimicrobial therapy.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.42-51
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• 2000

Antimicrobial activity and antioxidative activity of the organosoluble extractives from the leaves, bark and xylem of Quercus dentata were investigated. Antimicrobial activity was tested by paper disk method and bioautography methods, The most pronounced antimicrobial activities of leaves parts were ethyl acetate solubles fraction against the Klebsiella pneumoniae by the paper disk method. The strongest activities of bark parts were ethyl acetate solubles fraction against Bacillus subtilis, Klebsiella pneumoniae. Ethanol extractives from xylem parts showed high activities against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae and Vibrio parahaemolyticus. These antimicrobial activities of ethanol extractives from Quercus dentata were in order to xylem > bark > leaves. The strong inhibition zones of the ethanol extractives and its fractions of xylem showed Rf values in 0.41~0.63. In leaves extractives, the petroleum ether solubles showed lower antioxidative activity and ethyl acetate insolubles showed higher antioxidative activity of 70% compared with the $EC_{50}$ values of the control. Antioxidative activity of bark and xylem extractives showed higher approximately 2 times than the control except the petroleum ether solubles.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.349-354
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• 2016

The emergence and dissemination of extended-spectrum ${\beta}$-lactamse (ESBL) producing Klebsiella pneumoniae isolates make it more difficult to treatment of bacterial infections. In our study, we detected ESBL genes and investigated antimicrobial susceptibility of K. pneumoniae isolates in Chungcheong province. In addition, clonality among the isolates was analyzed by repetitive element sequence (REP)-PCR. Twenty-one of 102 K. pneumoniae isolates produced CTX-M-14 and/or CTX-M-15 and showed high level (over 70%) resistance to third cephalosporins. CTX-M type ESBL producing K. pneumoniae strains isolated in our study showed diverse clonality and some of the isolates have been disseminated in the community. Enhancing infection control will be needed to prevent dissemination of the K. pneumoniae isolates. In addition, for more effective control of resistant bacteria it is considered necessary to monitor the database constructed through convergence of biological investigation and statistical analysis of antimicrobial resistance genes.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.63-68
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• 1991

Several arsenic compound-resistant bacteria were isolated from Jung-Rang stream. The isolates, D-3, D-12, and D-14 were characterized phenotypically and genetically, and identified as Serratia liquefaciens, Klebsiella oxytoca, and Klebsiella pneumoniae, respectively. A plasmid of 67kb was found in Klebsiella oxytoca D-12 and designated as pMH12. Transfer of this plasmid from D-12 to E. coli HB101 was occurred, and the resulting transconjugant strains expressed the same level of heavy metal resistance as the donor strain. The physical presence of this plasmid in transconjugant was detected with agarose gel electrophoresis. Arsenite-sensitive derivatives of isolate D-12 were obtained with Mitomycin C treatment which cured pMH12. Antibiotics and heavy metal resistances were also examined to be used as a proper marker for the isolates in gene cloning. Isolate D-12 has resistance to several heavy metal ions such as $Cd^{2+}$ , $Zn^{2+}$ and $Hg^{ 2+}$ Also, all the other arsenite resistant isolates showed resistance to several heavy metal ions and antibiotics.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.518.2-519
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• 1986

토양으로부터 분리한 질소고정균인 Klebsiella pneumoniae NFB320의 chromosomal DNA를 BamHI으로 절단하여 동일한 제한효소로 절단한 pBR322에 ligation시켜 E. coli HB101에 형질전환을 행하여 pullulanase activity를 나타내는 clone을 얻어내었다. 이 형질 전환체로부터 분리한 pullulanase 유전자가 재조합된 plasmid DNA는 약 10kb의 DNA단편을 가지고 있었으며, 재조합된 plasmid로부터 생산되는 pullulanase의 특성은 최적 활성 pH가 6.0이며, 효소의 pH안정성은 5-10이었다. 또한 형질 전환체로부터 생산되는 pullulanase의 localization,효소활성에 영향을 미치는 온도안정성 둥을 조사하였다.