• Proceedings of the Zoological Society Korea Conference
• /
• 1999.10b
• /
• pp.265.1-265
• /
• 1999

No Abstract, See Full Text

• Annals of Laboratory Medicine
• /
• v.38 no.6
• /
• pp.555-562
• /
• 2018

Background: The emerging mobile colistin resistance gene, mcr-1, is an ongoing worldwide concern and an evaluation of clinical isolates harboring this gene is required in Korea. We investigated mcr-1-possessing Enterobacteriaceae among Enterobacteriaceae strains isolated in Korea, and compared the genetic details of the plasmids with those in Escherichia coli isolates from livestock. Methods: Among 9,396 Enterobacteriaceae clinical isolates collected between 2010 and 2015, 1,347 (14.3%) strains were resistant to colistin and those were screened for mcr-1 by PCR. Colistin minimum inhibitory concentrations (MICs) were determined by microdilution, and conjugal transfer of the mcr-1-harboring plasmids was assessed by direct mating. Whole genomes of three mcr-1-positive Enterobacteriaceae clinical isolates and 11 livestock-origin mcr-1-positive E. coli isolates were sequenced. Results: Two E. coli and one Enterobacter aerogenes clinical isolates carried carried IncI2 plasmids harboring mcr-1, which conferred colistin resistance (E. coli MIC, 4 mg/L; E. aerogenes MIC, 32 mg/L). The strains possessed the complete conjugal machinery except for E. aerogenes harboring a truncated prepilin peptidase. The E. coli plasmid transferred more efficiently to E. coli than to Klebsiella pneumoniae or Enterobacter cloacae recipients. Among the three bacterial hosts, the colistin MIC was the highest for E. coli owing to the higher mcr-1-plasmid copy number and mcr-1 expression levels. Ten mcr-1-positive chicken-origin E. coli strains also possessed mcr-1-harboring IncI2 plasmids closely related to that in the clinical E. aerogenes isolate, and the remaining one porcine-origin E. coli possessed an mcr-1-harboring IncX4 plasmid. Conclusions: mcr-1-harboring IncI2 plasmids were identified in clinical Enterobacteriaceae isolates. These plasmids were closely associated with those in chicken-origin E. coli strains in Korea, supporting the concept of mcr-1 dissemination between humans and livestock.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.4
• /
• pp.428-435
• /
• 2019

The rapid increase and dissemination of carbapene mases, such as Klebsiella pneumoniae carbapenemase (KPC), has become a major problem within the field of healthcare-related infection. There are few antibiotics to treat carbapenem-resistant Enterobacteriaceae (CRE) infections, so the identification of resistant bacterial mechanisms is critical to initiate infection control and conduct epidemiological research. A rapid and effective method for detecting KPC-producing bacteria is needed to avoid therapeutic failures and introduce measures to prevent and control the dissemination of these multi-resistant bacteria. During the study period, 31 isolates (seven isolates of Acinetobacter spp., six isolates of Morganella morganii, five isolates of Pseudomonas aeruginosa, five isolates of Proteus mirabilis, one isolate of Proteus vulgaris, two isolates of Enterobacter cloacae, one isolate of Enterobacter aerogenes, one isolate of Klebsiella pneumoniae, one isolate of Klebsiella oxytoca, one isolate of Serratia marcescens and one isolate of Escherichia coli) were identified by the VITEK. Gram negative rod bacteria were the most frequently isolated from urine (35.5%), blood (19.4%), sputum (16.1%), pus (9.7%), ascitic fluid (9.7%), tracheal aspirates (6.5%) and bile juice (3.2%). Analysis using the PCR method identified the bla_KPC gene in the K. oxytoca1 strain, but the bla_IMP, bla_VIM and bla_OXA-48 genes are not amplified. In conclusion, diagnosis using the PCR method can accurately and quickly diagnose KPC, thus establishing quick preventive measures to prevent the spread of KPC in hospitals.

• KSBB Journal
• /
• v.26 no.4
• /
• pp.328-332
• /
• 2011

Ethanol production using glycerol as a carbon source was performed by Enterobacter aerogenes immobilized on calcium alginate beads. To improve the ethanol production, the optimal conditions such as loading amount of immobilized cells and glycerol concentration were investigated. The optimal loading amount of immobilized cells and glycerol concentration were 10 mL of calcium alginate bead and 10 g/L, respectively. Consequently, glycerol consumption rate, ethanol concentration and yield were 0.32 g/$L{\cdot}h$, 3.38 g/L and 0.43 g/g on the batch production, respectively. Continuous production of ethanol was successfully achieved using two types of immobilized cell reactors (continuous stirred tank reactor and packed bed reactor) from 10 g/L of glycerol. In the continuous stirred tank reactor, glycerol consumption, ethanol concentration, specific productivity and yield were 9.8 g, 4.67 g/L, 1.17 g/$L{\cdot}h$, 0.48 g/g, respectively. The concentration of produced ethanol was 38-44% higher comparison to batch fermentation, and continuous stirred tank reactor showed better performance than packed bed reactor.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.41 no.2
• /
• pp.127-134
• /
• 2015

We investigated the growth-inhibitory activities of cosmetics and their preservatives against pathogens and resident skin bacteria. Of the tested cosmetics, preservatives such as parabens, 1,2-hexanediol, phenoxyethanol-contained toner, emulsion, cream and baby cream exhibited potent antibacterial effects against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Parabens, 1,2-hexanediol and phenoxyethanol inhibited the growth of pathogens, as well as skin-resident bacteria such as Staphilococcus epidermidis, Shigella flexneri, Enterobacter aerogenes and so on. The application of a basic cream containing phenoxyethanol to human skin was shown to disturb the skin microbiota: at the phylum level, Proteobacteria increased and at species level, 4P004125_s increased and Propionibacterium humerusii decreased. Based on these findings, parabens, 1,2-hexanediol and phenoxyethanol have antimicrobial activity and cosmetics containing phenoxyethanol may disturb skin microbiota.

• Korean Journal of Microbiology
• /
• v.47 no.4
• /
• pp.335-341
• /
• 2011

In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.

• Microbiology and Biotechnology Letters
• /
• v.46 no.2
• /
• pp.102-110
• /
• 2018

A bacterial strain capable of metabolizing myo-inositol (MI) and converting to other substances was isolated from soil of orchard. The isolate, named YB-46, was grown on minimal medium supplemented with MI as the sole carbon source and was presumed to belonging to genus Enterobacter according to the 16S rDNA sequence. Escherichia coli transformant converting MI into unknown metabolites was selected from a metagenomic library prepared with fosmid pCC1FOS vector. Plasmid was isolated from the transformant, and the inserted gene was partially sequenced. From the nucleotide sequence, an iolG gene was identified to encode myo-inositol dehydrogenase (IolG) consisting of 336 amino residues. The IolG showed amino acid sequence similarity of about 50% with IolG of Enterobacter aerogenes and Bacillus subtilis. The His-tagged IolG (HtIolG) fused with hexahistidine at C-terminus was produced and purified from cell extract of recombinant E. coli. The purified HtIolG showed maximal activity at $45^{\circ}C$ and pH 10.5 with the highest activity for MI and D-glucose, and more than 90% of maximal activity for D-chiro-inositol, D-mannitol and D-xylose. $K_m$ and $V_{max}$ values of the HtIolG for MI were 1.83 mM and $0.724{\mu}mol/min/mg$ under the optimal reaction condition, respectively. The activity of HtIolG was increased 1.7 folds by $Zn^{2+}$, but was significantly inhibited by $Co^{2+}$ and SDS.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.23 no.1
• /
• pp.1-6
• /
• 1990

The degradation of non-volatile-amines by microorganisms were investigated. The degra-ding activity could be noted in four strains isolated from fermented sardine sauce, and those were Pseudomonas aeruginosa, Pseudomonas fluorescens P-2, Pseudomonas fluorescens P-3 and Enterobacter aerogenes. The strongest degrading activity of non-volatile-amines was showed in Pseudomonas fluorescens P-3 among the four strains isolated. The optimum temperature for degradation by Pseudomonas fluorescens P-3 was $35^{\circ}C$, corresponding to the optimum temperature for growth of this strain, pH between 7.0 and 7.5 could gave effective degradation and the optimum concentration of NaCl was 0 and/or $1\%$.

• Archives of Pharmacal Research
• /
• v.12 no.2
• /
• pp.119-124
• /
• 1989

Cotton xanthate, which was obtained by treating cotton with carbon disulfide in alkaline solution, was treated with the solution of polyvalent metal ions to produce cotton xanthate-metal chelates. This chelation reaction was readily and simply achieved, and antimicrobial agents with suitable structures could subsequently be coupled to the chelate with ease at moderate pH values and in aqueous solution. Metal ions used in present work include Cu(II), Zn(II) and Fe(III). Tetracycline, streptomycin, neomycin and pyrithion were used as antimicrobial/antifungal agents. Antibacterial activities were measured employing ditch plate method against G(+) Staphylococcus aureus, Streptococus faecalis, and G(-) Escherichia coli, Enterobacter aerogenes, and the fungus, Aspergillus niger. All the cotton xanthate-metal-antimicrobial agent chelates exhibited activities whereas the cotton xanthate-metal chelates themselves were inactive. Considering the extensive washing procedures and results from control experiments, possibility of the involvement of physical adsorption for the binding of drugs could be excluded.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.1
• /
• pp.135-142
• /
• 1996

대나무잎(신의대)을 70% ethanol로 $80\pm2^{\circ}C에서$ 추출하고 극성이 다른 4가기 용매로 확분하여 생리활성 및 항균성을 검토하였다. 70% ethanol extract는 높은 항산화력을 나타내었고, 70% ethanol extract로부터 얻어진 각 용매별 추출 획분이 지질과 산화물 생성 억제와 malonaldehyde 생성 억제 효과는 ethyl acetate 획분 $\geq$ diethyl ether 획분 $\geqpetroleum$ ether 획분 > n-butanol 획분 > 수용성 획분의 순이었다. 전자공여능, 아질산염 제거능 및 항보체 활성은 n-butanol 획분이 다른 획분에 비하여 가장 높은 효과를 보였고 70% ethanol extract의 경우에도 전자고영능, 아질산염 제거능 및 항보체 활성이 높게 나타났다. 미생물인 Vib-rio parahaemoluticus, Pseudomonas aeruginosa, Salmonella typhimurium, Enterobacter aerogenes, Staphylococcus aureus 등에서 항균력을 나타내었다.