• 한국동물위생학회지
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• 제44권4호
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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.

• 한국식품위생안전성학회지
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• 제32권2호
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• pp.129-134
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• 2017

병원성 대장균군은 전세계적으로 식중독을 발생하는 중요한 병원균으로 알려져 있다. 국내 유통중인 생닭과 조리된 닭가공품 356시료에서 대장균 80균주(22.5%)를 분리하여 병원성 유전자 multiplex PCR를 이용하여 분석한 결과 astA 유전자가 26균주(32.5%)에서 검출되었으며, escV 유전자는 17균주(21.3%) eaeA 유전자는 16균주(20.0%) 검출되었다. 특히 식품에서 문제가 되는 장출혈성 대장균 유전자 stx 1는 3균주(3.8%)와 stx 2, EHEC-hly는 각 1균주(1.3%)에서 검출되었다. 병원성 유전자를 토대로 STEC, EPEC, EHEC, EIEC or EAEC의 병원성 대장균으로 분류한 결과 45균주(56.3%)가 검출되었으며 typical EPEC, EIEC and ETEC의 병원성 대장균은 검출되지 않았다. STEC 병원성 대장균은 O152, O1, O116, O26, O25, O119, O153 혈청형이 분리되었다. 특히 생닭에서 병원성 대장균에 대한 검출률이 높으므로 생닭을 가공 조리 시 교차 오염이 발생하기 않도록 조리 도구, 조리 환경에 대한 철저한 관리가 필요하다고 생각된다.

• Journal of Microbiology
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• 제44권5호
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• pp.548-555
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• 2006

FaeG is the key factor in the infection process of K88ad enterotoxigenic Escherichia coli (ETEC) fimbrial adhesin. In an attempt to determine the possibility of expressing recombinant FaeG with immunogenicity for a new safe and high-production vaccine in E. coli, we constructed the recombinant strain, BL21 (DE3+K88), which harbors an expression vector with a DNA fragment of faeG, without a signal peptide. Results of 15% SDS-polyacrylamide slab gel analysis showed that FaeG can be stably over-expressed in BL21 (DE3+K88) as inclusion bodies without FaeE. Immunoglobulin G (IgG) and M (IgM) responses in pregnant pigs, with boost injections of the purified recombinant FaeG, were detected 4 weeks later in the sera and colostrum. An in vitro villius-adhesion assay verified that the elicited antibodies in the sera of vaccinated pigs were capable of preventing the adhesion of K88ad ETEC to porcine intestinal receptors. The protective effect on the mortality rates of suckling piglets born to vaccinated mothers was also observed one week after oral challenge with the virulent ETEC strain, $C_{83907}$ (K88ad, $CT^+,\;ST^+$). The results of this study proved that the adhesin of proteinaceous bacterial fimbriae or pili could be overexpressed in engineered E. coli strains, with protective immune responses to the pathogen.

• 미생물학회지
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• 제16권4호
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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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• 제24권3호
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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.

• 대한의생명과학회지
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• 제13권1호
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• pp.47-53
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• 2007

Due to wide abuse of antibiotics both in human and livestock use, the advent and spread of multidrug resistant (MDR) pathogens becomes a serious health problem all over the world. Since the development of new antibiotics is at a standstill in pharmaceutical industry, the choice of therapeutic antibiotics is getting narrower. In this study, in an effort to search new antibiotics, the antimicrobial activity of Paenibacillus DY1 isolated from Korean soil was characterized on its growth inhibition spectrum against various health threatening MDR strains, with its stability and chemical structure. Extracellular culture filtrate of Paenibacillus DY1 effectively inhibits the growth of all the tested MDR enteropathogenic Eshcherichia coli, enterohemolytic E. coli, and enterotoxigenic E. coli strains, at a similar level to that on the nonresistant control E. coli strains. It showed significant growth inhibition effect against the causative agents of class one legal communicable disease, MDR Salmonella typhi, MDR Salmonella paratyphi A, food poisoning bacteria, MDR Salmonella typhimurium, and other MDR Salmonella spp. The growth of all of 10 different MDR Shigella spp. strains and 6 different Vibrio spp. strains tested was also inhibited. The antimicrobial activity of Paenibacillus DY1 was well preserved after heat treatment, and was also stable in both alkaline and acidic environment. The antimicrobial activity was partially purified with Diaion HP20 column and TLC. By NMR study, the putative structure of the activity was postulated as an alkane having hydroxyl groups.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권1호
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• pp.79-86
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• 2022

Purpose: To determine the effect of zinc deficiency on fecal protein, electrolyte, and short-chain fatty acid levels in both heat-stable (ST) and heat-labile (LT) enterotoxigenic Escherichia coli (ETEC)-induced diarrhea in rats. Methods: Albino rats, weighing 100 to 150 g, were divided into 2 groups, with 15 animals each: non-zinc and zinc-deficient. These two groups were sub-divided into three sub-groups with five rats each: control (saline); LT-ETEC; and ST-ETEC. Sodium phytate (30 mmol/L) was added to the animals' water to induce zinc deficiency, while diarrhea was induced using 5×10⁹ ETEC cells/mL. Fecal protein levels were estimated using the Bradford method, while sodium and potassium levels were determined using atomic absorption spectrophotometry. Short-chain fatty acids were measured using gas chromatography-mass spectrometry. Results: Among the non-zinc and zinc-deficient groups, there were significant increases (p=0.04), (p=0.03) in fecal protein concentrations (mg/mL) in the LT-ETEC- (4.50±0.33), (6.50±0.26) and ST-ETEC- (3.85±0.19), (5.98±0.32) induced groups compared to the control groups (2.60±0.52), (3.50±0.11) respectively. Fecal sodium and potassium levels (mg/L) were significantly (p=0.029) increased in non-zinc-deficient rats induced with LT-ETEC (9.35±0.95, 1.05±0.48), and ST-ETEC (9.96±1.02, 1.21±0.45) compared with the control group (8.07±0.44, 0.47±0.17) but the increase were not statistically significant (p=0.059) in the zinc deficient rat groups. Fecal acetate and propionate levels (mg/g) significantly (p=0.032) increased when induced with LT-ETEC and ST-ETEC in non-zinc and zinc-deficient groups compared with the control groups. Conclusion: Zinc deficiency among rats with ETEC-induced diarrhea elevated fecal protein loss but may not have an effect on fecal sodium, potassium and short-chain fatty acid levels.

• Journal of Animal Science and Technology
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• 제44권5호
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• pp.633-642
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• 2002

1. ETEC F41 균주로부터 분리한 섬모항원의 분자량은 29.5 kDa으로 나타났으며, western blot을 통하여 섬모항원임을 확인하였다. 2. 분리한 섬모항원의 농도를 50 ${\mu}g$/$m\ell$, 200 ${\mu}g$/$m\ell$, 600 ${\mu}g$/$m\ell$로 조정 후 산란계에 접종하였다. 이 후 ELISA법을 이용하여 난황의 항체역가를 측정한 결과 최고치가 320,000(antigen 50${\mu}g$/$m\ell$), 450,000(antigen 200${\mu}g$/$m\ell$), 320,000(anti- gen 600${\mu}g$/$m\ell$)으로 나타났다. 3. F41난황항체와 K88, K99, 987P 섬모항원과의 교차반응을 ELISA법을 이용하여 조사해본 결과 난황항체를 30,000배 희석 시 교차반응이 없었다. 4. 실험실조건하에서 난황항체의 항원결합능력을 조사한 결과, 동결건조한 WSF을 2${\sim}$4 mg/$m\ell$ 첨가 시 균체의 농도가 $10^9$ CFU/$m\ell$에서 $10^5$ CFU/$m\ell$로 급격하게 감소하였다.

• Parasites, Hosts and Diseases
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• 제55권5호
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• pp.513-521
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• 2017

Infectious diarrhea is endemic in most developing countries. We aimed to investigate the protozoan, viral, and bacterial causes of acute diarrhea in Taif, Saudi Arabia. A cross-sectional prospective 1-year study was conducted on 163 diarrheal patients of various ages. Stool samples were collected, 1 per patient, and tested for 3 protozoa, 3 viruses, and 9 bacteria with the Luminex Gastrointestinal Pathogen Panel. Overall, 53.4% (87/163) of samples were positives (20.8% protozoa, 19.6% viruses, 2.8% bacteria, and 9.8% mixed). Rotavirus (19.6%), Giardia duodenalis (16.5%), and Cryptosporidium spp. (8.5%) were the mostly detected pathogens. Adenovirus 40/41 (4.2%), Salmonella (3%), Shiga toxin-producing Escherichia coli (3%), and Entamoeba histolytica (2.4%) were also detected. Norovirus GI/II, Vibrio cholerae, Yersinia enterocolitica, and Clostridium difficile toxin A/B were not detected in any patients. All pathogens were involved in coinfections except E. histolytica. Giardia (5.5%) and rotavirus (3%) were the most commonly detected in co-infections. Enterotoxigenic E. coli (2.4%), Campylobacter spp. (2.4%), E. coli 0157 (1.8%), and Shigella spp. (1.2%) were detected in patients only as co-infections. Infections were more in children 0-4 years, less in adults <40 years, and least >40 years, with statistically significant differences in risk across age groups observed with rotavirus (P<0.001), Giardia (P=0.006), and Cryptosporidium (P=0.036) infections. Lastly, infections were not significantly more in the spring. This report demonstrates the high burden of various enteropathogens in the setting. Further studies are needed to define the impact of these findings on the clinical course of the disease.

• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.777-785
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• 2010

The effect of two doses of different sources of zinc, inorganic (zinc oxide) or chelated (zinc glutamate chelate), on morphology and turn-over of the small intestine was assessed in early-weaned pigs orally challenged with enterotoxigenic E. coli K88 (ETEC). Sixty pigs weaned at 21 days were assigned to one of the following 5 diets: control (C); C+Zinc oxide (ZnO), either a 200 or a 2,500 mg Zn/kg dose; or C+zinc chelate with glutamic acid (Glu-Zn), either a 200 or a 2,500 mg Zn/kg dose. On d 2, the pigs were orally inoculated with 1.5 ml of a $10^{10}$ CFU/ml E. coli K88ac O148 suspension. Zinc supplements did not improve the performance of the pigs, but on d 5 faecal excretion of ETEC was reduced, and this was mainly due to high zinc doses (p<0.05). The villous height in the duodenum was improved by the zinc supplements (p<0.01) whatever the source and the level, whereas no effect was seen in the other two tracts of small intestine. The diet did not affect apoptosis and mitosis counts, while ETEC-susceptible pigs had more mitotic cells in the villi than non-susceptible pigs, particularly in the jejunum (p<0.01). The duodenum had fewer mitotic cells in the villi (p<0.05) and in the crypts (p<0.01) and more apoptotic cells in the villi. High dietary doses of ZnO or Zn-Glutamate improve villous height of the duodenum, but not of the jejunum and the ileum, and do not affect the epithelial proliferative activity and apoptotic index of intestinal mucosa of early-weaned pigs orally challenged with ETEC.