• Korean Journal of Veterinary Service
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• v.43 no.2
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• pp.53-58
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• 2020

Enterovirulent Escherichia coli are among the most important causes of diarrhea in cattles. Between January and December, 2017, a total of 150 stool specimens from cattles were investigated for enterohaemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterotoxigenic E. coli (ETEC) and enteroinvasive E. coli (EIEC) using real-time PCR. 131 E. coli were isolated from feces. The most frequently isolated pathotype in feces was EHEC (37 isolates). EPEC, ETEC and EAEC were detected in feces with 14, 7 and 3 respectively. EIEC was not detected. Antimicrobial resistance test was performed by agar disc diffusion method with 14 antimicrobials. Enterovirulent E. coli isolates showed the highest antimicrobial resistance to ampicillin 61.3%, followed by tetracycline 54.5% and streptomycin 45.5%. They had low resistance to amikacin 11.4%. Of 44 isolates, 37 (84.1%) were resistant to more than 2 antimicrobials. futher study a highest antimicrobial susceptibility to trimethoprim/sulfamethoxazole 50.0% and florofenicol 47.7%.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.878-882
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• 2008

The efficacy of citric acid-aqueous chlorine dioxide ($ClO_2$) treatment of radish seeds artificially contaminated with Escherichia coli was studied. Radish seeds were inoculated with E. coli. Following inoculation, samples were stored at $4^{\circ}C$ and soaked in citric acid or aqueous $ClO_2$ for 10 min. The treatment of radish seeds using 200 ppm aqueous $ClO_2$ solution caused a 1.5 log CFU/g reduction in the population of E. coli. Compared to the aqueous $ClO_2$ treatment, soaking radish seeds in 2.0% citric acid solution for 10 min was more effective in reducing E. coli populations on radish seeds. The efficacy of spray application of chlorine (100 ppm) or 0.5% citric acid to eliminate E. coli during the germination and growth of radish was investigated. Radish seed inoculated with E. coli was treated for the duration of the growth period. Although it resulted in a decrease in the E. coli population, the spray application of 100 ppm chlorine during the growth period was not significantly effective. In contrast, the combined treatment of seeds using 200 ppm aqueous $ClO_2$ and treatment of sprouts with 0.5% citric acid solution during sprout growth was hardly effective in eliminating E. coli.

• Journal of Dairy Science and Biotechnology
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• v.39 no.2
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• pp.51-62
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• 2021

Escherichia coli are the predominant facultative bacteria found in the gastrointestinal tract of animals and humans. Some strains of E. coli that acquire virulence factors and cause foodborne and waterborne diseases in humans are called pathogenic E. coli and can be divided into five pathotypes according to the virulence mechanism: EAEC, EHEC, EIEC, EPEC, and ETEC. Although selective media have been developed to detect E. coli, distinguishing pathogenic strains from non-pathogenic ones is difficult because of their similar biochemical properties. Therefore, it is very important to find a new and effective diagnostic method to identify pathogenic E. coli. With recent advances in molecular biology and whole genome sequencing, the use of polymerase chain reaction (PCR) is increasing rapidly. In this review paper, we provide an overview of pathogenic E. coli and present a review on PCR detection methods that can be used to diagnose pathogenic E. coli. In addition, the possibility of real-time PCR incorporating IAC is introduced. Consequently, this review paper will contribute to solving the current challenges related to the detection of pathogenic E. coli.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.16-20
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• 1989

The effect of E. coli plasmid DNA sequences contained by chimeric vectors on plasmid replication was investigated. We constructed YRp7- or 2.$\mu$m circle-based plasmids containing E. coli plasmid DNA sequences and those not containing it. By examining their maintenance in yeast, we showed that plasmid without E. coli plasmid DNA sdquences was nore stable and presented higher copy number, and espressed higher level of hepatitis B viral surface antigen as a foreign gene. This result suggested that E. coli plasmid DNA sequences within chimeric plasmid somehow inhibited plasmid replication in yeast.

• Food Science of Animal Resources
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• v.40 no.4
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• pp.668-674
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• 2020

Manuka honey (MH) has been shown anti-bacterial activity against several pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation by Escherichia coli O157:H7 has not yet been examined. In this study, MH significantly reduced E. coli O157:H7 biofilm. Moreover, pre- and post-treatment with MH also significantly reduced E. coli O157:H7 biofilm. Cellular metabolic activities exhibited that the viability of E. coli O157:H7 biofilm cells was reduced in the presence of MH. Further, colony forming unit of MH-treated E. coli O157:H7 biofilm was significantly reduced by over 70%. Collectively, this study suggests the potential of anti-biofilm properties of MH which could be applied to control E. coli O157:H7.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.237-246
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• 1988

The higher bacterial numbers on clay than on sand were caused by different environmental factors. Such factors affecting the adsorption of E. coli ATCC 11775 in the sediment as follows; optimal pH range for the adsorption of E. coli ATCC 11775 was pH 7.5-pH 9.5. E. coli ATCC 11775 were shown maxima in the salinity of 18.$75%_{o}$ on sand type sediment and $12.5%_{o}$ on clay type sediment. Bacteria attached better to clay typed sediment than to sand typed sediment when organic substance was eliminated. Beef extract of 0.5%-1% concentration was found to promote the attachment of E. coli ATCC 11775 effectively. Peptone of 0.5% was enganced the attachment on the clay, and peptone of 1.3%-5%, on the sand. E. coli ATCC 11775 was found to adsorb onto benthonite with the highest efficiency and on celite with the lowest efficiency. Efficiency of adsorption by inorganic ions was shown due to higher values of ion. Adsorption was achieved in the order of $Al^{3+}, Ca^{2+}, Na^{+}$.

• The Journal of the Korean Society for Microbiology
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• v.12 no.1
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• pp.1-10
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• 1977

40 strains of E. coli isolated from residents of a doctorless area in Korea in 1976 and 40 strains of E. coli isolated from patients of Seoul National University Hospital from 1975 to 1976 were examined for susceptibilities to 14 antimicrobial agents by the agar dilution method. The susceptibilities of the two groups to each antimicrobial agent were compared and correlations in the antimicrobial susceptibility of the 80 strains of E. coli among the 14 antimicrobial agents were also analyzed. The results were obtained as follow: 1. With Tetracycline, Oxytetracycline, Doxycycline and Ampicillin, the mean MIC's of E. coli isolated from patients of Seoul National University Hospital were 8.6 to 14 times higher than. those of E. coli isolated from residents of a doctorless area. 2. With Streptomycin, Minocycline and Carbenicillin, the mean MIC's o{ E. coli isolated from patients of Seoul National University Hospital were 4.1 to 5.6 times higher than those of E. coil isolated from residents of a doctorless area. 3. With Kanamycin, Penicillin and Cotrimoxazole, the mean MIC's of E. coli isolated from patients of Seoul National University Hospital were 2.6 to 3.7 times higher than those of E. coli isolated from residents of a doctorless area. 4. There were no significant differences in susceptibility to Erythromycin respectively between E. coli isolated from patients of Seoul National University coli isolated from residents of a doctorless area. 5. E. coli isolated from patients of Seoul National University Hospital were resistant to Erythromycin(100%), Streptomycin(75%), Tetracycline(72.5%), Oxytetracycline(72.5%), Doxycycline(72.5%), Minocycline(67.5%), Penicillin(82.5%), Ampicillin(60%) and Carbenicillin(65%) respectively and were sensitive to Gentamicin(97.5%), Cephalexin(92.5%) and Kanamycin(72.5%) respectively. 6. E. coli isolated from residents of a doctorless, area were resistant to Erythromycin(100%), Streptomycin(40%) and Penicillin(50%) respectively and were sensitive to Gentamicin(100%), Kanamycin(92.5%), Tetracycline(87.5%), Oxytetracycline(87.5%), Doxycycline(87.5%), Minocycline(87.5%), Ampicillin(95%), Carbenicillin(92.5%) and Cephalexin(97.5%) respectively. 7. There were high correlations among the suscebtibilities of the 80 strains of E. coli to Tetracycline analogues(Tetracycline, Oxytetracycline, Doxycycline and Minocycline) and among susceptibilities of the 80 strains of E. coli to Penicillin analogues(Penicillin, Ampicillin and Carbenicillin). 8. There were relatively high correlations between the susceptibilities of the 80 strains of E. coli to Penicillin analogues and those to Tetracycline analogues, between the susceptibilities to Penicillin analogues and those to Streptomycin and between the susceptibilities to Tetracycline analogues and those to Streptomycin.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.169-175
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• 2001

This study was conducted to investigate the effects of bifidobacteria on the growth and Caco-2 cell-adherence of Escherichia coli O157:H7 .Dur-ing momo-culture of E. coli O157:H7 and mixed culture with Bifidobacterium infantis K9, pH viable cell count, and ammonia concentration were measured Co-cultivation of E. coli O157:H7 with bifidobacteria. producing acidic metabolites rapidly decreased the viable cell count of E. coli O157:H7 In addition rapid decrease of ammo- nia concentration was observed during mixed culture after 8 hrs incubation compared to single culture of E. coli O157:H7 Therefore it is likely that bifidobacteria assimilate ammonia produced by E. coli O157:H7 P4 B, infantis K9 showed quite similar adherence on the Caco-2 cells in either case. On the other hand adherence of E. coli O157:H7 decreased from 2.6% to 1.86% when B infantis K9 was adhered to Caco-2 cell 2 hrs prior to the application of E. coli O157:H7 In conclusion in adherence of E coli O157:H7 to Caco -2 cell was inhibited by competition of its binding to the adherence site with bifidobacteria. In addition inhibitory effects of bifidobacteria on E coli O157:H7 appeared to be much higher with increae of the number of bifidobacteria and its ability of adherence to Caco-2 cells.

• Clinical and Experimental Pediatrics
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• v.50 no.5
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• pp.457-461
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• 2007

Purpose : Urinary tract infection (UTI) is a common bacterial infectious disease in childhood. Especially UTI in infant and young children is associated with urinary tract anomalies such as hydronephrosis, vesicoureteral reflux. The aim of this study was to compare the clinical and laboratory characteristics, and uroradiologic findings of UTI caused by pathogens other than E. coli with UTI caused by E. coli in infant and young children. Methods : We retrospectively reviewed medical records of 170 infants and children, who had been admitted for UTI to Il Sin Christian Hospital from January 2003 to December 2005. All patients were divided into two groups; E. coli and non-E. coli UTI, and they were compared for demographic data, clinical data (degree and duration of fever, time to defervescence, and length of hospital stay), underlying urinary tract anomalies (by history and ultrasonography), recurrent infection (by history and past medical records), and laboratory data [urinalysis, white blood cells (WBC) count in peripheral blood, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum creatinine level]. Results : Of the 170 UTI patients, the number of non-E. coli UTI was 114 (67.1%) and E. coli UTI was 56 (32.9%). As compared to E. coli group, non-E. coli group was younger in age ($0.52{\pm}0.59years$ vs $0.84{\pm}1.39years$, P<0.05), had higher rates of urinary tract anomalies [n=46 (82.1%) vs n=53 (46.5%), P<0.001], higher recurrence rate, shorter time to defervescence, less peripheral blood WBC count, lower level of CRP, lower level of ESR. Conclusion : The characteristics of non-E. coli UTI compared to E. coli UTI was younger age, milder clinical symptoms and signs, higher rates of urinary tract anomalies and higher recurrence rate.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.415-419
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• 2006

The epoxide hydrolase (EH) of Rhodotorula glutinis which has a high enantioselectivity against aromatic epoxide substrates was expressed to high levels in Escherichia coli based on codon usage. We analysed the Preference of codon usage between the yeast, R. glutinis, and bacteria, E. coli. E. coli, Rosetta(DE3)pLysS, harbors pRARE plasmid with tRNA genes for rare-codons was employed as a host strain. The recombinant E. coli expressing R. glutinis EH showed an enhanced enantioselective hydrolysis activity toward racemic styrene oxide. Enantiopure (S)-styrene oxide with a high enantiopurity of 99% ee (enantiomeric excess) was obtained from racemic substrates.