• 대한의생명과학회지
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• 제24권1호
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• pp.1-8
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• 2018

${\mu}MT$ knockout mice are genetically deficient in the transmembrane domain of mu chain of the immunoglobulin M (IgM) heavy chain, resulting in the absence of mature B cells. ${\mu}MT$ knockout mice is an in vivo model system used to clarify the role of B cells in various diseases. Enteropathogenic Escherichia coli (EPEC) induces acute and chronic diarrheal disease, especially in children of developing countries. The formation of attaching and effacing (A/E) lesion is a prominent pathogenic factor in the intestinal epithelium of EPEC infection. The A/E lesion is modulated by genes located on the pathogenic island locus of enterocyte effacement (LEE) which encode a type III secretion system (T3SS) and A/E lesion-related effector proteins. Citrobacter rodentium is a murine pathogen utilized in studying the pathogenic mechanisms of EPEC in human infections. Citrobacter rodentium produce A/E lesion to attach to intestinal epithelium, thus providing a murine model pathogen to study EPEC. Several studies have investigated the pathogenesis of Citrobacter rodentium in the ${\mu}MT$ knockout mice. In this review, we introduce the ${\mu}MT$ murine model in the context of C. rodentium pathogenesis and describe in detail the role of B cells and antibodies in this disease.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2003년도 추계학술대회초록집
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• pp.33-33
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• 2003

There prevalence of $\beta$-lactamases bacteria in animals has been increased since 1990s [1]. The resistance in E coli which is mediated by $\beta$-lactamases hydrolyze the $\beta$-lactam ring eventually inactivate the antibiotics [2]. Generally, $\beta$-lactamases can be classified into four main groups and eight subgroups according to their functional and structural characteristics [3]. The detection of $\beta$-lactam antibiotic-resistant bacteria by DNA chip has been described [4]. The chip has a specific probe DNAs that contained the $\beta$-lactam antibiotic-resistant genes which was labeled by multiplex PCR reaction with a mixture of primer sets that were designed to amplify specific gene. Here we report the susceptibility of enteropathogenic E. coli isolated from pigs in Korea using the DNA chip in detecting $\beta$-lactam antibiotic-resistant genes. (omitted)

• 한국식품위생안전성학회지
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• 제4권2호
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• pp.155-163
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• 1989

YS-medium(0.1% Yeast extract +10% Skimmilk)중에 유산간균 L.casei, L. acidophilus , L. bulgaricus 와 병원성 E, coli, Sal. enteritides를 혐기적으로 혼합배양하면서 각각의 생육과 저해를 조사한 결과 , E. coli와 Sal. enteritideis의 생육이 각 유산균에 의하여 현저하게 저해되었다. 그러나 L.casei와 L.acidophilus의 각 유산균은 E.coli와 Sal. enteritidis에 의하여 생육이 전혀 저해되지 않았고 , L. bulgaricus는 E. coli 에 의하여 약간 저해를 받았다. E. coli와 Sal. enteritidis 의 단독배양액의 pH는 72시간째에 각각 5.08과 5.70이었으며, 유산균혼합배양액의 pH는 3.75~4.48이었고, 병원성균의 생육억제작용은 주고 pH 저하에 기인하였다.

• Fisheries and Aquatic Sciences
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• 제16권4호
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• pp.221-227
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• 2013

In total, 131 Escherichia coli isolates from surface seawater of the Gomso Bay, of Korea, were analyzed for their susceptibility to 22 different antimicrobials and for genes associated with antimicrobial resistance and virulence. According to the disk diffusion susceptibility test, the resistance to tetracycline was most prevalent (33.6%), followed by that to ampicillin (22.1%), ticarcillin (22.1%), and trimethoprim (16.8%). More than 46.6% of the isolates were resistant to at least one antimicrobial, and 22.9% were resistant to three or more classes of antimicrobials; these were consequently defined as multidrug resistant. We further found that 29 ampicillin-resistant isolates possessed genes encoding TEM-type (93.1%) and SHV-type (6.9%) ${\beta}$-lactamases. Among the 44 tetracycline-resistant isolates, tetA and tetC were found in 35 (79.5%) and 19 (43.2%), respectively, whereas tetB was detected in only three isolates (6.8%). With regard to virulence genes, merely 0.8% (n = 1) and 2.3% (n = 3) of the isolates were positive for the enteroaggregative E. coli-associated plasmid (pCVD432) gene and the enteropathogenic E. coli-specific attaching and effacing (eae) gene, respectively. Overall, these results not only provide novel insight into the necessity for seawater sanitation in Gomso Bay, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.

• 대한수의학회지
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• 제22권2호
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• pp.155-159
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• 1982

A polyvalent live Escherochia coli oral vaccine were prepared by the use of 5 field isolates of enteropathogenic E. coli, serotypes 08 : K87, K88a, b ; 0138 : K81, K88a, c ; 0141 : K85a, b, K88a, b ; 0149 : K91, K88a, c and 0157 : K'V17', K88a, c. Some field experiments were conducted to investigate the effectiveness of the polyvalent live E. coli oral vaccine in the prevention of neonatal colibacillosis in piglets suckling orally vaccinated sows. Seventy-nine pregnant sows in an intensive pig farm were vaccinated with oral vaccine 4 weeks prior to farrowing and 19 sows were chosen for control. The piglets suckling vaccinated sows showed a significant protection against neonatal enteric colibacillosis during the 2 weeks observation period from the farrowing but no significant differences in protection between vaccinated and control group were observed with piglets older than 15 days.

• Journal of Microbiology
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• 제45권1호
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• pp.29-33
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• 2007

Salmonella typhimurium, causing mouse typhoid, infects hosts such as macrophage cells, and proliferates in intracellular vacuoles causing infected cells to trigger numerous genes to respond against the infection. In this study, we tried to identify such genes in RAW264.7 cells by using the PCR screening method with degenerate primers. Fourteen genes were found to be differentially expressed after a 4 h infection in which the expression of 8 genes increased while expression of the others decreased. Most of the genes were involved in proinflammatory responses such as cytokines production and cell death. The mutation in msbB gene encoding the myristoyl transferase in lipid A of lipopolysaccharide (LPS) resulted in much lower toxicity to the inoculated animals. We compared the expression of the identified genes in wild-type and msbB-mutated S. typhimurium infections and found that Lyzs encoding lysozyme type M was differentially expressed. This gene is quite likely to be related to bacterial survival in the host cells.

• 대한미생물학회지
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• 제22권4호
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• pp.413-425
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• 1987

In the present experiments, isolated Vibrio species from marine and clinical specimens from July, 1985 to October, 1986, had the results as follows: 1. The 55 strains of Vibrio were isolated and identified; Vibrio parahaemolyticus was 35 strains, Vibrio vulnificus was 10 strains, Vibrio alginolyticus was 10 strains. 2. In the K-serotyping of Vibrio parahaemolyticus, fourteen serotypes identified but three were not strains typable by the availble K-antisera. 3. In the Kanagawa phenomenon experiment of Vibrio parahaemolyticus, it proved positive reaction, 14 of 15 strains(93%) isolated from the patient and 13 of 20 strains(65%) isolated from the nature. 4. In twelve antibiotic resistance experiments, Vibrio parahaemolyticus and Vibrio alginolyticus showed 100% resistance on ampicilline, but Vibrio vulnificus showed 100% sensitivity. But all of them proved 100% sensitivity on chloramphenicol, tetracycline, nalidixic acid. 5. In the antibiotic resistance patterns, Vibrio parahaemolyticus proved that 15 strains(43%) resisted on 4 antibiotics and 5 strains(14%) resisted on 7 antibiotisc and. Vibrio vulnificus proved that 1 strain(10%) resisted on 2 antibiotics and 6 strains(60%) without resistance, Vibrio alginolyticus proved that 7 strains(70%) resisted on 3 antibiotics and 2 strains(20%) resisted on 8 antibiotics.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.354-361
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• 2005

Vibrio fluvialis, an enteropathogenic bacterium, produces a phospholipase which is thought to be an important factor in the pathogenesis of disease. In this study, the phospholipase gene (vfp) was identified from V fluvialis (KCTC 2473) and its sequence was determined. The entire open reading frame was composed of 1,689 nuc1eotides and 563 amino acids. The phospholipase gene (vfp) was overexpressed in Escherichia coli as a his-tag fused protein. This recombinant protein (rVFP58) was solubilized with 6 M urea and purified by Ni-NTA affinity chromatography. The action mode of rVFP58 was determined by TLC and GC-MS, and it showed phospholipase B activity, which had both phospholipase A and lysophospholipase activities. The rVFP58 showed a maximum activity at pH around 9- 10 and temperature of about 40OC, and it was stable under alkaline condition over pH 9. The cytotoxicity of rVFP58 was evaluated, using a fish cell line, CHSE-2l4, and was found to cause significant cell death after 14 h of exposure to 250 $\mu$g of the protein.

• 한국동물위생학회지
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• 제43권2호
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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%.

• 한국동물위생학회지
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• 제42권1호
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• pp.9-15
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• 2019

Transmissible gastroenteritis (TGE) is a disease confined to pigs of all ages, and can be a significant cause of economic loss in breeding herds, primarily because of the very high piglet mortality. The causative agent is a coronavirus, an enveloped positive strand RNA virus and closely related but non-enteropathogenic porcine respiratory coronavirus (PRCV). Although the TGEV has declined with its innocent relative, PRCV, further genome changes could not be excluded. Therefore, the herd-level immunity against this virus is important for the prevention of disease and should be carefully monitored. The aim of this study is to develop monoclonal antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) which can rapidly and accurately determine a large numbers of serum samples for surveillance purpose, and to compare the ELISA with a TGEV-specific serum neutralization test. The MAC-ELISA was sufficiently achieved, and the comparison with the virus-specific serum neutralization assays for 713 sera from pig farms showed a high correlation ($r^2=0.812$, P<0.001). The specificity and sensitivity of MAC-ELISA for the serum neutralization test 91.9% and 91.6%, respectively, which means that the antibody detected by the MAC-ELISA could be said to be protective antibodies. In conclusion, the developed MAC-ELISA would be very helpful in evaluating protective antibodies against TGEV.