• Journal of Microbiology
• /
• v.45 no.1
• /
• pp.69-74
• /
• 2007

Escherichia coli is a clonal species, and occurs as both commensal and pathogenic strains, which are normally classified on the basis of their O, H, and K antigens. The O-antigen (O-specific polysaccharide), which consists of a series of oligosaccharide (O-unit) repeats, contributes major antigenic variability to the cell surface. The O-antigen gene cluster of E. coli O66 was sequenced in this study. The genes putatively responsible for the biosynthesis of dTDP-6-deoxy-L-talose and GDP-mannose, as well as those responsible for the transfer of sugars and for O-unit processing were identified based on their homology. The function of the wzy gene was confirmed by the results of a mutation test. Genes specific for E. coli O66 were identified via PCR screening against representatives of 186 E. coli and Shigella O type strains. The comparison of intergenic sequences located between galF and the O-antigen gene cluster in a range of E. coli and Shigella showed that this region may perform an important function in the homologous recombination of the O-antigen gene clusters.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.4
• /
• pp.479-483
• /
• 2006

We developed a microfluidic immunoassay platform for the detection of various analytes such as bacterial pathogen by packing antibody-immobilized glass beads in spatially-isolated microchambers on a microfluidic device. Primary amines of antibody were covalently conjugated to carboxyl-terminated glass beads previously treated with aminosilane followed by glutaraldehyde. Through this covalent binding, up to 905 $\mu$g immunoglobulin G (IgG) per gram of glass beads was immobilized. For application, glass beads attaching antibody specific to Escherichia coli O157:H7, a foodborne pathogen, were packed into a microfluidic device and used for the detection of the serotype. This prototype immunoassay device can be used for the simultaneous detection of multiple analytes by sequentially packing different-sized glass beads attaching different antibody in discrete microchambers on a single microfluidic device.

• Journal of Environmental Health Sciences
• /
• v.20 no.2
• /
• pp.90-98
• /
• 1994

Introduction : Bovine mastitis is an economically and a hygienically important disease of dairy cows. Many factors predispose to bovine mastitis and an understanding of these is essential for systems of effective mastiris control to be formulated. The presence of non-pathogenic bacteria on body surfaces can protect against invasion by more pathogenic organisms. Bacteria of low pathogenicity (minor pathogens) are frequently isolated from the healthy bovine udder and may play an important role in protecting the udder from infection with pathogenic bacteria. The treatment of bovine mastitis is important for choosing adequate antimicrobias, and it take the base on the result of susceptibility to antimicrobias. Therefore, the current of numbers feeding dairy cattle were increasing and prevalence rate of bovine mastiris was occurred in 1.5~57.3%.(abbreviation)

• Microbiology and Biotechnology Letters
• /
• v.31 no.1
• /
• pp.32-35
• /
• 2003

This study was carried out to determine the inhibitory effect of garlic juice against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Shigella flexneri. Staphylococcus aureus, Streptococcus mutans, Virio. parahaemolyticus which are food pathogenic bacteria and Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus casei, Lactobacillus plantarum, Lactococcus. lactis, Leuconostoc mesenteroides which are lactic acid bacteria. An aqueous extract of garlic was bacteriocidal against Gram-positive and Gram-negative bacteria in all concentrations (0.1∼2.5(w/v)%) tested in this experiment. Especially 0.5(w/v)% garlic juice inactivated completely E. coli, S. typhimurium, S. flexineri, V. parahaemolyticus and 1.0(w/v)% garlic juice perfectly reduced P. aeruginosa, S. mutans. Generally, the experiment result indicate that garlic juice restrains the growth of the pathogenic bacteria better than the lactic acid bacteria. Therefore, garlic has potential for the preservation of processed foods.

• Journal of Veterinary Clinics
• /
• v.24 no.4
• /
• pp.636-639
• /
• 2007

Septicemic polyserositis and navel ill associated with Escherichia coli were reported in a 14-day-old male thoroughbred foal. The horse died after showing 12-day history of anorexia, lethargy, lameness and endophthalmus. Grossly, milky yellow abscesses were occupied in umbilicus, umbilical vein and artery. Large amounts of turbid pale yellow fluids were seen in pericardial sac, thoracic and abdominal cavity. Yellowish fibrinous materials were also presented in thoracic and abdominal cavity. Sticky pale yellow fluid and fibrinous materials were filled in stifle joint cavities of both hind limbs. Histologically, fibrino-purulent polyserositis and arthritis were observed. Severe omphalophlebitis with intra-lesional Gram negative bacterial colonies were noted in umbilical vein. Most of mesothelial cells in serosal cavities were severely hypertrophied. Pathogenic E. coli was purely isolated from ascites, thoracic and synovial fluids. Based on the results, the septicemic polyserositis may be originated from the umbilical cord infected with E. coli in this foal.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.5
• /
• pp.602-611
• /
• 2022

The persistence of pathogenic Escherichia coli under acidic conditions poses a serious risk to food safety, especially in acidic foods such as kimchi. To identify the bacterial factors required for acid resistance, transcriptomic analysis was conducted on an acid-resistant enterotoxigenic E. coli strain and the genes with significant changes in their expression under acidic pH were selected as putative resistance factors against acid stress. These genes included those associated with a glutamate-dependent acid resistance (GDAR) system and copper resistance. E. coli strains lacking GadA, GadB, or YbaST, the components of the GDAR system, exhibited significantly attenuated growth and survival under acidic stress conditions. Accordantly, the inhibition of the GDAR system by 3-mercaptopropionic acid and aminooxyacetic acid abolished bacterial adaptation and survival under acidic conditions, indicating the indispensable role of a GDAR system in acid resistance. Intriguingly, the lack of cueR encoding a transcriptional regulator for copper resistance genes markedly impaired bacterial resistance to acid stress as well as copper. Conversely, the absence of YbaST severely compromised bacterial resistance against copper, suggesting an interplay between acid and copper resistance. These results suggest that a GDAR system can be a promising target for developing control measures to prevent E. coli resistance to acid and copper treatments.

• Korean Journal of Veterinary Research
• /
• v.50 no.3
• /
• pp.239-246
• /
• 2010

Among 203 avian pathogenic Escherichia coli (APEC) isolated from poultry with colibacillosis in korea, 14 isolates were selected from total 68 isolates transferred R plasmid and classified into 5 groups on the basis of antimicrobial minimal inhibitory concentration (MIC) pattern, farm source and O serotype. An association between clonal origin and R plasmid of them was investigated by R plasmid profile, restriction endonuclease analysis and pulsed-field gel electrophoresis (PFGE). The strains that showed the same or very similar antimicrobial MIC pattern, but different farm source and O serotype, revealed different PFGE pattern, which seemed to be different clonal origin. And the strains that showed the same MIC pattern and O serotype, revealed different PFGE pattern, seemed to be originated from different clone. Also the strains showing the same MIC pattern and farm source, but different O serotype, revealed to be different clonal origin. The strains that showed the same or similar MIC pattern, farm source, and O serotype, revealed identical or similar PFGE pattern, which seemed to belong to be one clone. Meanwhile, horizontal transfer of R plasmid seems to be common in APEC with regardless of O serotype and clone of the strains. These results indicate that rapid and accurate epidemiological survey of APEC can be possible by the combination of O serotyping, plasmid profiling and PFGE analysis following the classification of them into groups of antimicrobial drug resistance pattern.

• Journal of Food Hygiene and Safety
• /
• v.31 no.6
• /
• pp.393-398
• /
• 2016

The objective of this study was to isolate pathogenic Escherichia coli from fresh vegetables with selective media and Petrifilm, and identify a suspicious colony using biochemical identification. Twenty gram of lettuce, twenty gram of cabbage and ten gram of sprout were prepared, and a 5-strain mixture of pathogenic E. coli (Enterohemorrhagic E. coli NCCP11142, Enterotoxigenic E. coli NCCP14037, Enteropathogenic E. coli NCCP14038, Enteroaggregative E. coli NCCP14039, Enteropathogenic E. coli NCCP15661) was inoculated to obtain 1, 2 and 3 log CFU/g. Eighty to ninety milliliter of buffered peptone water (BPW) was placed and pummeled for 60 s. As a results, the Petrifilm method was all positive, but enrichment method of qualitative analysis was negative except for 3-log CFU/g inoculated lettuce. Regarding biochemical identification of pathogenic E. coli, the identification rates were dependent on type of methods and vegetables; lettuce: API 20E 100% (44/44), Microgen GNA 100% (44/44) and Food System 66.7% (10/15), cabbage: API 20E 64.7% (22/34), Microgen GNA 50% (16/32) and Food System 60% (9/15), sprout: API 20E 65.1% (28/43), Microgen GNA 62.3% (27/43) and Food System 53.3% (8/15). These results could be useful in determining an appropriate method to detect pathogenic E. coli in fresh vegetables.

• Journal of Dairy Science and Biotechnology
• /
• v.15 no.1
• /
• pp.11-20
• /
• 1997

This study was designed to carry out an observation on the growth inhibitory effect of fermented milk by the the lactic acid bacteria such as Lactobacillus bulgaricus, L. acidophilus and L. cormatus against pathogenic Escherichia coli O157:H7 were studied in vitro. The results of this study were as follows : The BL broth culture of L. bulgaricus, L. acidophilus and L. cormatus gave a similar extent of growth inhibitory effects against the pathogenic E. coli O157:H7 were after incubation time within 18 hours. The inhibitory effects of the fermented milk were observed on the survival time of pathogenic E. coli O167:H7 in the various fermented milk at 37${\circ}$C shaking water bath (70 rpm) were after incubation time between 140 and 200 minutes. These results indicated that major portion of growth inhibitory effects of fermented milk with various lactic acid bacteria against pathogenic E. coli O157:H7 was possible due to the acid, and minor portion to the other antibacterial substances.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.5
• /
• pp.1063-1066
• /
• 2004

The rpoS gene product is a global transcriptional factor, which is involved in bacterial survival under various stress conditions. An rpoS-homologous gene was cloned from a septicemia-causing pathogenic Vibrio vulnificus. Introduction of this gene as a multicopy plasmid into various E. coli strains displayed functional complementation, for examples, increased survivability of an rpoS-defective E. coli cell and induction of known $\delta^S$-dependent, stress-responding promoters of E. coli genes.