• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.111-119
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• 2013

The aim of this study was to investigate the isolation frequency and antimicrobial resistance of Escherichia coli (E. coli) and Enterococcus spp. from domestic beef and pork on sale in Seoul, Korea. A total of 106 (10.4%) E. coli and 114 (11.2%) Enterococcus spp. from 635 domestic beef and 381 pork samples were isolated and examined for susceptibility to 15 and 11 antimicrobial agents, respectively. The most frequent antimicrobial resistance observed in E. coli isolates was to ampicillin (38.6%), followed by streptocmycin (34.9%) and tetracycline (32.0%). The most frequent antimicrobial resistance in E. faecium isolates was to erythromycin (53.8%) and rifampin (46.1%), and in E. faecalis isolates was to tetracycline (55.7%) and rifampin (55.0%). Among the isolates, multi-drug resistant (MDR) E. coli and Enterococcus spp. strains showing resistances to more than two antimicrobial agents tested were 10.4% and 11.2%, respectively. As a result, appropriate protocols for antimicrobial agents and strategies to reduce antimicrobial resistance will be needed in future.

• Journal of Environmental Science International
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• v.19 no.7
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• pp.889-900
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• 2010

The experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV process were mathematically described as a function of parameters power ($X_1$), NaCl dosage ($X_2$), initial pH ($X_3$) and disinfection time ($X_4$) being modeled by use of the Box-Behnken technique. The application of RSM using the Box-Behnken technique yielded the following regression equation, which is an empirical relationship between the residual E. coli number and test variables in actual variables: Ln (CFU) = 23.57 - 0.87 power - 1.87 NaCl dosage - 2.13 pH - 2.84 time - 0.09 power time - 0.07 NaCl dosage pH + 0.14 pH time + 0.03 $power^2$ + 0.47 NaCl $dosage^2$ + 0.20 $pH^2$+ 0.33 $time^2$. The model predictions agreed well with the experimentally observed result ($R^2$ = 0.9987). Graphical response surface and contour plots were used to locate the optimum point. The estimated ridge of maximum response and optimal conditions for the E. coli disinfection using canonical analysis was Ln 1.06 CFU (power, 15.40 W; NaCl dosage, 1.95 g/L, pH, 5.94 and time, 4.67 min). To confirm this optimum condition, the obtained number of the residual E. coli after three additional experiments were Ln 1.05, 1.10 and Ln 1.12. These values were within range of 0.62 (95% PI low)~1.50 (95% PI high), which indicated that conforming the reproducibility of the model.

• KSBB Journal
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• v.24 no.4
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• pp.341-346
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• 2009

Candida Antarctica lipase A (CalA) has been used because of its suitability in industrial applications. CalA has unique features capable to accept tertiary and sterically hindered alcohols among many hydrolases. CalA gene was cloned and constructed in expression vector such as pColdIII/CalA and $pPICZ{\alpha}A$/CalA. The gene encoding pColdIII/CalA was functionally expressed in the cytoplasm of Escherichia coli $Origami^{TM}$ B (DE3) cells. The plasmid $pPICZ{\alpha}A$/CalA linearized by BstX I was integrated into 5'AOX1 region of the chromosomal DNA and was functionally expressed in the methyl atrophic yeast Pichia pastoris. Expressed CalA in P. pastoris (0.7 Unit/mL) showed 35 times higher activity than that in E. coli expression system (0.02 Unit/mL).

• Food Science and Preservation
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• v.5 no.4
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• pp.380-385
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• 1998

The sensitivity of various pathogenic bacteria(Aeromonas hydrophila, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium) to the ethanol extract of pine needle was tested. Tryptic soy broth containing 0-2%(w/v) of the ethanol extract of pine needle was inoculated with 10$^4$-10$\^$6/ CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 48 hours. Gram positive bacteria(L. monocytogenes and S. aureus 196E) and 1 Gram negative bacteria(A. hydrophila) were more sensitive than E. coli O157:H7 and S. typhimurium in the ethanol extract of Pine needle. Gram negative bacteria(E. coli O157:H7 and S. typhimurium) were not inhibited at 1% and they were slightly inhibited at 2% ethanol extract of pine needle. S. aureus was the highest sensitivity, followed by A. hydrophila, L. monocytogenes E. coli O157:H7 in that order. S. typhimurium was the most resistant to the ethanol extract of pine needle.

• 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.

• Environmental Mutagens and Carcinogens
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• v.25 no.4
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• pp.157-160
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• 2005

Antibiotic resistance of bacteria in the biofilm mode of growth contributes to the chronicity of infection and disease. The penetration of antibiotic, through biofilm developed in an itt vitro model system was investigated. Antibiotic resistant bacteria (E. coli) were obtained from Culture Collection of Antibiotic Resistant Microbes. Ca-alginate bead used as simulated biofilm and a cell entrapment test using compressed air were experiment for the improvement cell viability. Antibiotic susceptibilities though biofilms was measured by assaying the concentration of antibiotic that diffused through the biofilm to minimal inhibition concentration (MIC). Survival of immobilized cells were reduced as compared to free cells. In case of antibiotic susceptible E. coli reduced continuously, but antibiotic resistant E. coli kept up survival rate constantly. Survival was showed after exposed to the antibiotics that the more treated antibiotic resistant E. coli and low concentration of antibiotics) the more survived.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.703-710
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• 2011

Enzymatic saccharification of corn stover using Phanerochaete chrysosporium and Gloeophyllum trabeum and subsequent fermentation of the saccharification products to ethanol by Saccharomyces cerevisiae and Escherichia coli K011 were achieved. Prior to simultaneous saccharification and fermentation (SSF) for ethanol production, solid-state fermentation was performed for four days on ground corn stover using either P. chrysosporium or G. trabeum to induce in situ cellulase production. During SSF with S. cerevisiae or E. coli, ethanol production was the highest on day 4 for all samples. For corn stover treated with P. chrysosporium, the conversion to ethanol was 2.29 g/100 g corn stover with S. cerevisiae as the fermenting organism, whereas for the sample inoculated with E. coli K011, the ethanol production was 4.14 g/100 g corn stover. Corn stover treated with G. trabeum showed a conversion 1.90 and 4.79 g/100 g corn stover with S. cerevisiae and E. coli K011 as the fermenting organisms, respectively. Other fermentation co-products, such as acetic acid and lactic acid, were also monitored. Acetic acid production ranged between 0.45 and 0.78 g/100 g corn stover, while no lactic acid production was detected throughout the 5 days of SSF. The results of our experiment suggest that it is possible to perform SSF of corn stover using P. chrysosporium, G. trabeum, S. cerevisiae and E. coli K011 for the production of fuel ethanol.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.213-217
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• 2013

The objective of this study was to investigate the effect of bacterial contamination on elapsed time after preservation on boar semen. Known numbers of Escherichia coli (E. coli) were inoculated to freshly ejaculated semen and sperm parameters such as viability, motility, agglutination, acrosome integrity and hypo-osmotic swelling test were performed during 7 days of liquid preservation. Semen samples were prepared using antibiotic free BTS extender and 4 different levels of E. coli were treated to semen with following concentrations; 3,000, 5,000, 7,000, 10,000 CFU/ml of sperms. Semen samples were preserved at $17^{\circ}C$ for 7 days in semen storage until analyzed. Aliquots were subjected to measure the sperm viability, motility and agglutination using computer assisted sperm analysis (CASA) system, acrosome integrity was performed using chlortetracycline (CTC) staining method and hypo-osmotic swelling test was performed using hypotonic solution from day 1 (day of semen collection) to 7. Detrimental effects on sperm motility and viability were observed 3 days after preservation at the level of 5,000 CFU/ml (p<0.05). Percentage of sperm abnormality was higher (p<0.05) in over 5,000 CFU/ml groups. Sperm agglutination rate was also significantly higher (p<0.05) in groups of 5,000 and 7,000 CFU/ml. The rate of acrosome reacted sperm was higher as preservation time goes in all the samples but the pattern was clearly higher among E. coli contaminated groups (p<0.05). The sperm membrane integrity in terms of hypo-osmotic test, E. coli affects little compared to other sperm parameters. The deleterious effects observed due to the bacterial contamination in semen suggest that importance of hygiene protocol to minimize the bacterial contamination during semen collection and processing.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.125-130
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• 2006

The emergence of extended spectrum ${\beta}$-lactamase producing bacteria is causing very serious problems in Korea. Although there have been many reports about these bacteria Isolated from patients and clinical specimens, there is no report of extended spectrum ${\beta}$-lactamase producing organisms isolated from natural environment in Korea. This study was conducted to investigate the biological characteristics and extended spectrum ${\beta}$-lactamase types of eighteen strains of extended spectrum ${\beta}$-lactamase producing Klebsiella pneumoniae and Escherichia coli isolated from a slaughterhouse in Pusan in Korea during 2002 to 2004. Extended spectrum ${\beta}$-lactamases were identified by double-disk synergy test, conjugation, isoelectric focusing values and gene sequencing. Eight strains of Klebsiella pneumoniae and two strains of Eschericha coli were isolated kom pigs and transferred extended spectrum ${\beta}$-lactamase genes to recipient Escherichia coli J53 (sodium azide resistant and ceftazidime senstive) strain by conjugation. The conjugants of extended spectrum ${\beta}$-lactamase genes were alignments and translated to amino acids by BCM and NCBI blast. Eight conjugants of Klebsiella pneumonae were typed TEM-52, and two strains of Escherichia coli, SHV-12, but CMY-1 type were not detected in this study.

• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.139-145
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• 1987

Adherence to HEp-2 cells has been proposed as a virulence characteristic of enteropathogenic E. coli (EPEC). The role of the HEp-2 adherent E. coli was evaluated in a group of children with endemic diarrhea admitted to Hanyang University Hospital in Seoul, Korea. HEp-2-adherent E. coli was detected in fecal samples of 59 (59%) of 100 cases and ten (22.7%) of 44 concurrent control children (p<0.0005). Adherence was exhibited by 15 serogroups and subgroups, but within these groups more than one adherence pattern was frequently observed. Of 17 strains belonging to traditional infantile EPEC serogroups, 12(70.6%) gave a positive adherence. Of 45 enterotoxin producing strains, 24 (53.3%) gave a positive adherence. HEp-2-adherent strains that did not belong to classic EPEC serogroups and did not produce heat-stable and/or heat-labile enterotoxins(referred as enteroadherent E. coli, EAEC) was found in 29 (29%) of the patients with diarrhea and in six (13.6%) of the well children (p<0.05). From 22 of the 29 cases, no pathogen other than EAEC was isolated. These findings strongly implicate EAEC as the cause of diarrhea in the children. Our study supports the concept that EAEC may be an important cause of endemic diarrhea in Korean children.