• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.117-126
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• 1998

This study was performed to investigate the immunogenicity of autogenous E coli vaccines and their preventive effects on diarrhea in suckling piglets. Autogenous E coli live and killed vaccines were made from the E coli strains isolated from piglets showing diarrhea in field. In group I, pregnant sows were administered with live and killed vaccines at 4 and 2 weeks before parturition, respectively, Killed vaccines were administered twice to pregnant sows at 4 and 2 weeks before parturition in group II, and saline instead of autogenous E coli vaccines was administered to pregnant sows in group III for the control. After parturition, antibody titers in colostrum and milk from sows, incidence of diarrhea in suckling piglets, and immunoreactivity in the ileum of piglets from each treatment group were examined. The results were as follows ; 1. Sixty-two strains of E coli were isolated from suckling piglets with diarrhea. Of the strains, K88 pilus and K99 pilus antigens were identified in 6(9.8%) and 4(6.5%), respectively. Molecular weights of K88 and K99 pilus were 27,500 and 18,500 daltons, respectively. 2. Antibody titers in colostrum from sows after parturition were 1 : 512 to 1 : 1,024 in group I, 1.256 to 1.512 in group II, and 1 : 4 to 1 : 16 in group III. 3. The incidences of diarrhea In suckling piglets of group I, II and III were 3.3%, 9.4% and 21.4%, respectively. 4. When the immunoreactivity in the ileum of piglets from each group was examined, the proportion of IgG-immunoreactivity cells in group I or II was higher than that in group III. In conclusion, administration of autogenous E coli vaccines to pregnant sows before parturition can be an effective way to prevent diarrhea in suckling piglets.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.76-83
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• 1992

Enterotoxigenic E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-stable enterotoxin (ST) is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a maker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. ST producing E. coli KM-7 strain was isolated from the swine and molecular cloning of ST gene of KM-7 strain. Transformant eKT-53 $(ST^+,\;LT^-)$ was selected by infant mouse assay (IMA). The culture supernatant of eKT-53 strain was performed purification by multipled steps. The culture supernatant (crude ST) was purified by sequentially applying batch adsorption chromatography on Amberlite XAD-2 resin, ion exchange chromatography on DEAE-Sephacel anion exchanger, gel filtration chromatography on Bio-Gel P-6 and preparative polyacrylamide slab gel electrophoresis. About 113-fold purification was achieved with a yield of about 11% of crude ST and the minimum effective dose(MED) of this purified ST was about 2.8ng in IMA. Homogeneity of purified ST was demonstrated by showing a single band in analytical SDS polyacrylamide disc gel electrophoresis.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.129-134
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• 2017

Diarrheagenic Escherichia coli is now recognized as an important cause of diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome (HUS) worldwide. E. coli were isolated from 80 of 356 (22.5%) chicken and chilled chicken products in Korea. Fifteen virulence genes specific for pathogenic E. coli, including Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and enteroaggregative E. coli (EAEC), were examined by multiplex PCR. STEC virulence markers were detected for eaeA (20.0%), escV (21.3%), stx1 (3.8%), ent (2.5%), EHEC-hly (1.3%), stx2 (1.3%), EAEC virulence marker (astA) was detected in 32.5%. ETEC and EIEC were not detected. STEC serotypes O152, O1, O116, O26, O25, O119 and O153 were found in chicken samples. This suggests the importance of diarrheagenic Escherichia coli control in raw chicken and chilled chicken food for food safety.

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

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.58-65
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• 2000

Diarrheal diseases are a major cause of both illness and death in developing countries and are caused by rotavirus, Shigella spp., Salmonella spp., enterotoxigenic Escherichia coli (ETEC), and Vibrio spp. In this study, for the development of vaccine against diarrheal diseases caused by Shigella sonei, Salmonella typhimurium, E. coli O157, and Vibrio cholerae, cloning and nucleotide sequence analysis of genes and characteristics of their gene products in E. coli were performed. For construction of attenuated strain of S. sonnei KNIH104 and Salmonella typhimurium KNIH100, the aroA genes were cloned, respectively. The recombinant plasmid $_pJP{\Delta}A45$ containing aroA deleted region and suicide vector $(_pJP5603)$ was constructed. The aroA gene deleted mutants were constructed using this recombinant plasmid. For cloning gene encoding antigenic region of E. coli O157 KNIH317, the O-antigen synthesis gene cluster and sit gene was cloned. The E. coli XL1-Blue cells harboring this recombinant plasmid showed cytotoxicity in Vero cells. The ctx gene was cloned for tile purpose of antigenic region against V. cholerae KNIH002. Sequence analysis confirmed that the virulence gene cassette was consisted of ace, zot, ctxA and ctxB genes.

• Korean Journal of Microbiology
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• v.16 no.4
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• pp.161-169
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• 1978

Escherichiae-like organisms were isolated from rectal specimens of 56 children who were either in preschool age or in elementary school. The isolated strains were subjected to tests to screen enteropathogens producing heat-labile enterotoxin and susceptibility test to various antibiotics by disc diffusion method on agar plates. Production of heat-labile enterotoxin by the strains was assyed in the sensitive and reproducible cultured adrenal tumor cell system. The assay was sterodogenesis of the cell in the presence of heat-labile enterotoxin. Among 56 strains, gave positive reaction in the test of toxin production. This meant that about 10% of the children population objected to the study harbored the toxigenic strain of enteropathogenes. Some of these toxigenic strains were resistant to the antibiotics employed in the test. This study suggested that considerable population in Korea may harbor entertoxigenic E. coli as a part of intestinal normal flora. The toxigenic strains which are resistant to antibiotics may bring issue of public health in the future.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.421-426
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• 2014

To characterize the extended-spectrum beta-lactamases (ESBLs) in diarrheagenic Escherichia coli from Korea in 2008-2011, we screened seven enterotoxigenic E. coli (ETEC) and one enteroaggregative E. coli (EAEC) that produce ESBLs from a nationwide survey. All eight isolates produced CTX-M-type ESBLs, including CTX-M-12 (n = 4), CTX-M-14 (n = 2), and CTX-M-15 (n = 2). PCR-based replicon typing indicated that the $bla_{CTX-M-12}$ genes of four ETEC isolates were carried on a conjugative IncF plasmid, whereas the $bla_{CTX-M-14}$ of one EAEC was located on an IncK plasmid. This is the first report of the occurrence of $bla_{CTX-M}$ genes in clinical isolates of EAEC in Korea. The ESBL-producing isolates were shown to be different based on pulsed-field gel electrophoresis and multilocus sequence typing, whereas the four isolates with CTX-M-12 were clonally related. These observations raise an alarm for the spread of plasmid-mediated resistance to ESBL among diarrheagenic E. coli.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.101-110
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• 2022

This study was performed to investigate infectious gastrointestinal diseases in 115 Korean cats (83 indoors and 32 outdoors) with digestive signs such as diarrhea, anorexia or abdominal distention. Detection of infectious pathogens was analyzed using real-time PCR. As a result, 85 of 115 Korean cats were detected with feline corona virus (FCoV), feline parvo virus, Group A rotavirus, Clostridium perfringens (C. perfringens), Campylobacter coli (C. coli), Campylobacter jejuni, enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli, Salmonella spp., Tritrichomonas foetus, Cyclospora cayetanensis, and Giardia lamblia. The most frequently detected pathogen was C. perfringens (52 cats, 61.2%), followed by FCoV (43 cats, 50.6%) and C. coli (16 cats, 18.8%). Also, single infection was the most common (43 cats), followed by double infection in 31 cats, triple infection in 7 cats, and quadruple infection in 4 cats. There was no significant relationship between pathogen detection and age, gender, living environment, weather, and diarrhea. However, there was a significant difference between the age group under 1 year and the age group 1~7 (P value<0.05). In this study, cats with suspected gastrointestinal infection were randomly evaluated, and other factors that could affect pathogen detection were insufficiently considered. For this reason, additional epidemiological investigations with a larger number of cats and sufficient consideration of the causes that may affect the results are needed. Nevertheless, it is thought that this study can also provide valuable information on gastrointestinal pathogens in Korean cats.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.126-131
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• 2015

Pathogenic Escherichia coli is recognized as an important cause of diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome worldwide. This study was conducted to investigate the prevalence E. coli contamination in the Korean traditional food bibimbap. E. coli were isolated from 84 of 1142 (7.3%) bibimbap investigated from 2005 to 2011. Antibiotic resistance profiling demonstrated that 6 of the 84 isolates (7.2%) showed multiple drug resistance. Fifteen virulence genes specific for pathogenic E. coli such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC) were examined by multiplex PCR for mixed bacterial cultures derived from bibimbap samples. The EPEC virulence gene (ent) was detected in 5 strains (5.9%), while ETEC, EAEC, and EIEC were not detected. STEC serotypes O103 (1.2%), O91 (1.2%), and O128 (6.0%) were found, but other serogroups such as O26, O157, O145, O111 and O121 were not detecded. Automated Repetitive-Sequence-Based PCR analysis showed different patterns.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.271-281
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• 2021

Pathogenic Escherichia coli (E. coli) is one among the most important agents of diarrhea in calves. From January to December 2021, 108 isolates from feces of calves with diarrhea were investigated for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), shiga toxin-producing E. coli (STEC), enteroaggregative E. coli (EAEC), and enteroinvasive E. coli (EIEC) using real-time PCR. In addition, the genes for F5, F17 and F41 fimbriae were detected by PCR. The most frequently isolated pathotypes were EPEC/STEC (29 isolates), and ETEC/EPEC/STEC (29 isolates). ETEC/EPEC, and ETEC/STEC were also found in 10 isolates. EPEC, STEC, and ETEC were detected in 13, 11, and 6 respectively. EAEC, and EIEC was not detected. Antimicrobial resistance test was carried out by agar disc diffusion method with 14 antimicrobials. Among 108 pathogenic E. coli isolates, 107 isolates were resistant to at least one of 14 antibiotics used in this study, 99 (91.7%) were resistant to two or more antimicrobials, and a single remarkable isolate was resistant to 14 antimicrobials. The isolates were primarily resistant to penicillins, streptomycin, tetracycline, ceftiofur, Trimethoprim/sulfamethoxazole, Kanamycin, and Ciprofloxacin. The high rate of resistance in pathogenic E. coli, sometimes to multiple drugs, may complicate future options for treating human infections. These results may bu used for diagnosis and therpeitic purposes in calves with diarrhea.