• Korean journal of food and cookery science
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• v.13 no.2
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• pp.106-112
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• 1997

The effect of low concentrations of allspice (Pimenta dioica L.) in culture broth as an antibacterial agent against Escherichia coli 0157:H7 and Staphylococcus aureus 196E was tested at 35,5 and -20$^{\circ}C$. Tryptic soy broth (TSB) containing 0∼2% (w/v) of allspice was inoculated with 10$\^$5/∼10$\^$6/ cells/$m\ell$ of E. coli and S. aureus and incubated at each temperature. The growth of E. coli was not inhibited at 0.1∼1.0% allspice and growth occured at 2％ allspice but only after a prolonged lag period. Growth of S. aureus was inhibited with increasing concentration of allspice at 35$^{\circ}C$. Growth of S. aureus occured at the presence of 0.1∼0.3% allspice but the viability of S. aureus at 0.5∼2.0% allspice was decreased during storage at 35$^{\circ}C$. During refrigerated storage at 5$^{\circ}C$, inhibition of E. coli and S. aureus was increased with the progress of time and increasing spice concentration. During frozen storage at -20$^{\circ}C$, antibacterial activity of allspice against E. coli was increased with increasing storage time and spice concentration while that activity against S. aureus was effective during early period of storage. There was no major changes in population of S. aureus in TSB with different concentration of spice frozen at -20$^{\circ}C$. Viable counts of E. coli and S. aureus at 0.l％ of allspice was less than that of control during frozen storage.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.385-392
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• 2008

In this study, seawater intrusion was assessed employing a kind of biological parameters such as Escherichia coli and Enterococcus faecalis while lab-prepared reclaimed water was recharged to prevent seawater intrusion. Chemical factors indicating seawater intrusion such as Cl$^-$, Ca$^{2+}$, Mg$^{2+}$ and specific conductivity were also simultaneously investigated where an ion exchange between a matrix in artificial aquifer and cations in solution was estimated. Both Escherichia coli and Enterococcus faecalis were shown to be very sensitive against degree of salinity during saline water intrusion. Enterococcus faecalis more strongly resisted against salinity than that of Escherichia coli. The ratio of Enterococcus faecalis divided by E. coli in the process of seawater intrusion increased up to more than 50$\sim$100 times in 18 hours whereas E. coli was died off more than 90% during pumping and recharge rate kept at 10 mL/min. However, when the rates of both recharge and pumping was kept at 5 mL/min, Enterococcus faecalis / Escherichia coli was sustained in the range of 2.5$\sim$5.0, while Escherichia coli showed dimished death rate. Chemical factors such as Cl$^-$, Ca$^{2+}$, Mg$^{2+}$ and specific conductivity showed more than 0.9 of high correlation each other well explaining the degree of seawater intrusion. The degree of ion exchange between artificial aquifer and saline water can be efficiently interpreted by both minus $\Delta$Na, $\Delta$Mg variation and positive $\Delta$Ca variation.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.37.1-37.8
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• 2022

Background: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, resulting in significant economic losses in the poultry industry. Objectives: In this study, the molecular characteristics of two extended-spectrum beta-lactamase (ESBL)-producing APEC isolates were compared with previously reported ESBL-producing E. coli isolates. Methods: The molecular characteristics of E. coli isolates and the genetic environments of the ESBL genes were investigated using whole genome sequencing. Results: The two ESBL-producing APEC were classified into the phylogenetic groups C and B1 and ST410 and ST162, respectively. Moreover, the ESBL genes of the two isolates were harbored in different Inc plasmids. The EC1809182 strain, harboring the bla_CTX-M-55 gene on the plasmid, exhibited extensive homology to IncFIB (98.4%) and IncFIC(FII) (95.8%). The EC1809191 strain, harboring the bla_CTX-M-1 gene, was homologous to IncI1-I (Gamma) (99.3%). All chromosomes carried the multidrug transporter, mdf(A) gene. Mobile genetic elements, adjacent to CTX-M genes, facilitated the dissemination of genes in the two isolates, analogous to other ESBL-producing E. coli isolates. Conclusions: This study clarifies the transmission dynamics of CTX-M genes and supports strengthened surveillance to prevent the transmission of the antimicrobial-resistant genes to humans via the food chain.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.73-78
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• 1997

Purpose : Escherichia coli O157 can produce diarrhea as well as hemorrhagic colitis and hemolytic uremic syndrome. In many parts of North America, E. coli O157 often is the second or third most commonly isolated enteric bacterial pathogens. Recently, intakes of fast food, including hamburgers have increased in Korea. Therefore, E. coli O157 infection in Korea are likely to be increased. Methods : Stool samples from 317 pediatric diarrheal patients were analyzed by culture on sorbitol-MacConkey agar. Sorbitol-negative colonies were teated by E. coli O157 latex agglutination test. Results : Of the 317 specimens, one (0.3%) were E. coli O157:NM that not produced Shiga toxin. The 7 year old male patient who had complained of abdominal pain, vomiting and non-bloody diarrhea for 2 days. The patient was improved for 2 days after admission. Conclusions 1 Only one (0.3%) of all fecal samples were isolated E. coli O157 that not produced Shiga toxin. Therefore, routine stool culture for the isolation of E. coli O157 was not likely to be neccessary so far.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.1
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• pp.33-39
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• 2022

Objective: Male genital tract infections have been associated with infertility, and Escherichia coli has drawn increasing attention as an important bacterium in this context. This investigation aimed to characterize and compare the distributions of O-antigen serogroups of E. coli in the semen samples of fertile and infertile men. Methods: In this case-control study, semen samples were collected from 618 fertile and 1,535 infertile men. The E. coli-positive samples were evaluated in terms of concentration, morphology, viability, and motility parameters according to the World Health Organization 2010 guidelines. Finally, different serogroups of E. coli were identified by multiplex polymerase chain reaction targeting the O-antigen variations of the bacterium. Results: The prevalence of E. coli among fertile men was significantly higher than among infertile men (p<0.001). The sperm morphology, viability, and motility in the E. coli-positive fertile group were significantly higher than in the E. coli-positive infertile group (p<0.001). E. coli O6 was the most prevalent serogroup found in both groups. However, there was no significant difference in the frequency of different serogroups of E. coil between the two groups (p=0.55). Conclusion: Despite the higher prevalence of E. coli among fertile men, E. coli had more detrimental effects on semen parameters in infertile men. There was no significant difference in E. coli serogroups between the fertile and infertile groups.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.571-575
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• 2004

Escherichia coli O157:H7 cause hemorrhagic colitis and the extraintestinal complication of hemolytic-uremic syndrome, with their higher incidence occurring in children. Lipopolysaccharide (LPS) of E. coli O157:H7 is very important to make IgG anti-LPS with bactericidal activity. To identify the characteristic of E. coli OI57:H7, we isolated 60 MDa plasmid and amplified stx genes of shiga-like toxin (Stx) 1, 2 of E. coli O157:H7 by polymerase chain reaction (PCR) method. Using the simple purification method which contained phenol extract, ethanol precipitation and gel filtration steps, the LPS of E. coli O157:H7 was isolated and purified. Finally, we confirmed the purity of LPS through SDS-PAGE and silver nitrate staining.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.73-81
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• 2012

Objectives: With the goal of quantifying the risk of children contracting gastroenteritis while playing at interactive waterscape facilities and evaluating the adequacy of current water quality regulations, risk assessment was performed with Escherichia coli as pathogen. Methods: Abundances of E. coli in the waters of interactive water features in South Korea were acquired from survey reports. A gamma distribution describing the volume of water swallowed by children during swimming activities was adopted. Exposure rate and risk were calculated by Monte Carlo simulation and dose-response models for various pathogenic E. coli. Results: E. coli was detected in 25 out of 40 facilities, with range of ~1,600 CFU/100 ml. The abundance fitted an exponential distribution. Simulated exposures ranged ${\sim}1.9{\times}10^{10}$ CFU, varying greater along E. coli abundance than the volume of water. Risk of children being infected by enterohemorrhagic E. coli was high, with range of ~0.85. When E. coli abundance was <200 CFU/100 ml, which is the current government threshold, the risk decreased to <0.43. Although the guideline successfully reduced the risk of adults being infected by a less virulent E. coli strains (<0.03), the risk for children could not be quantified due to lack of dose-response models for those pathogens for children. Conclusions: Under the current guideline, children are at risk of being infected if water is contaminated with by enterohemorrhagic E. coli. For other E. coli strains, the risk appears to be considerably less. The result warrants need for developing dose-response models for children for each pathogenic E. coli strain.

• BMB Reports
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• v.29 no.2
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• pp.116-121
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• 1996

In earlier studies, the genes encoding Escherichia coli thioredoxin and Corynebacterium nephridii thioredoxin C-3 were fused via a common restriction site in the nucleotide sequence coding for the active site of the proteins to generate two chimeric thioredoxins, designated E-C3 (N to C-terminal) and C3-E. The hybrid thioredoxins were overexpressed in E. coli from the cloned chimeric thioredoxin genes by a T7 promoter/polymerase system. To investigate the structure-function relationship of thioredoxin, we purified the E-C3 hybrid thioredoxin through ammonium sulfate fractionation, DEAE-cellulose chromatography, and Sephadex G-50 gel filtration. Its purity was examined on SDS-polyacrylamide gel electrophoresis and the molecular weight of the purified E-C3 hybrid thioredoxin was estimated to be 12,000. On native polyacrylamide gels, the purified E-C3 hybrid thioredoxin shows a much lower mobility than E. coli thioredoxin. E-C3 hybrid thioredoxin exhibits a 40-fold lower catalytic efficiency with E. coli thioredoxin reductase than E. coli thioredoxin. It was shown to catalyze the reduction of insulin disulfide by dithiothreitol. The purified E-C3 hybrid thioredoxin was also characterized in other aspects.

• Korean Journal of Veterinary Research
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• v.57 no.3
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• pp.189-195
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• 2017

The isolation rate of Escherichia (E.) coli in poultry litter was investigated at 44 broiler farms, 20 that used fresh litter and 24 that used recycled litter. The patterns of resistance to antibiotics of the E. coli isolates were compared. In litter sampled before the rearing period, the isolation rate of E. coli was higher at farms that used fresh litter; E. coli was present in the litter in 94.5% (35 out of 37 flocks tested) of the farms that used fresh litter vs. 51.2% (21 out of 41 flocks) of the farms that used recycled litter. The susceptibility of the 93 isolates of E. coli to 13 antibiotics was studied. Before the rearing period, E. coli isolates from the farms that recycled litter showed higher resistance rates than isolates from farms that replaced litter with fresh litter. Comparing the antibiotic resistance patterns of isolates from litter sampled before and at the end of the rearing period, the antibiotic resistance rates at the end of the rearing period increased dramatically compared with rates before the rearing period.

• Food Science and Preservation
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• v.7 no.1
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• pp.124-131
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• 2000

Antibacterial activities of powdered spices(garlic , ginger, cinnamon and clove) against pathogenic Escherichia coli )157:H7 and Staphyloccus auresus were investigated. Spice powder was added in was exponetial phase of each bacterial culture . Growth inhibition was determined by the absorbance at 660nm and morphological changes of the cells were observed by transmission electron microscope (TEM). Ginger powder has the highest antibacterial activity, following cinnamon , clove and garlic has the least activity.Growth of Escherichia coli O157:H7 and Staphyloccus aureus were completely inhibited within 5 hours after addition of 1 % of garlic , 0.3% of ginger or cinnamon , 0.5% of clove powder on the exponential phase of the cells. Spice untreated cells of E. coli and S. aureus, the cytoplasm was entirely surrounded by rigid cell wall and cell walls formed a smooth layer well attached to the plasma membrane. In the cells of E. coli and S. aureus treated with spice powder, cell wall and plasma membrane were lysed and severely damaged. E.coli cells growth in the presence of spice powder showed plammolysis, the loss of electron dense material, the formation of extra cellular blebs and cytoplasm burst out from the cell. S .sureus cells grown in the presence of spice powder showed swell of cell wall, the loss of electron dense material , coagulation of cell cytoplasm and formation of extra cellular blebs. Severely damaged cells of S. aureus lost whole cytoplasm and left as ghost of the cell. Spice powder stimulated autolyssi and induced cell death.