• 농업생명과학연구
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• 제46권2호
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• pp.107-114
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• 2012

The present study evaluated the potential use of immunoglobulin prepared from egg yolk of chickens immunized with Escherichia coli K88 (IgY-Ec) in the control of E. coli K88 infection in RAW 264.7 murine macrophage. The binding activity of IgY-Ec against E. coli K88 surface protein was more specific and increased than control IgY. In infection assay of E. coli in macrophage, the specific IgY-Ec to E. coli K88 remarkably inhibited the phagocytic activity comparing to nonspecific IgY (p<0.001). In adherence assay, bacterial adhesion on macrophage cells was definitely reduced by preincubation of IgY-Ec compared with nonspecific IgY (p<0.05). These findings suggested that IgY-Ec have the protective effects against pathogens and IgY-based diets may have potential benefits for preventing or treating various infections in domestic animals.

• Pediatric Infection and Vaccine
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• 제22권3호
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• pp.194-200
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• 2015

목적: 요로감염은 소아에서 흔한 세균 감염이며, Escherichia coli가 주요 원인균이다. 본 연구는 우리나라에서 소아 요로감염을 일으키는 E. coli의 계통 분류와 독성인자를 분석하고자 하였다. 방법: 2010년 10월부터 2013년 4월까지 요로감염으로 입원한 33명의 소아 환자로부터 검출된 E. coli균주를 대상으로 하였다. 중합효소연쇄반응을 통해 E. coli의 계통 분류 및 5가지 독성인자(fimH, sfa, papA, hylA, and cnf1)를 조사하였다. E. coli의 분자유전학적 특징을 환자의 임상적 진단과 동반된 방광요관 역류에 따라 분석하였다. 결과: 대부분의 요로병원성 E. coli 는 계통 분류에서 B2군(84.8%)에 속했으며, 나머지는 모두 D군(15.2%)에 해당되었다. 독성인자는 fimH (100%), sfa (100%), hylA (63.6%), cnfI (63.6%), 그리고 papA (36.4%)의 분포를 보였다. 임상 진단에 따른 계통 분류에서 급성 신우신염의 경우 B2군이 92.3%, D군이 7.7%를 나타냈으며, 방광염에서는 B2군에서 57.1%, D2군은 42.9%였다. 독성인자는 양 군에서 비슷하게 분포하였다. 급성 신우신염에서 방광요관 역류의 유무에 따른 계통 분류의 분포에는 차이가 없었으나, 독성인자의 경우 papA 유전자가 방광요관 역류가 동반되지 않은 군에서보다 방광요관 역류 군에서 적게 나타났다(43.8% vs. 20.0%, P=0.399). 결론: 본 연구는 국내 소아 요로감염의 원인 E. coli 균주의 분자유전학적 역학 자료를 제시하였으며, 이 결과는 향후 소아 요로감염의 발생 기전을 이해하는 데 기초가 될 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.333-340
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• 2020

Macrophages are the cells of the first-line defense system, which protect the body from foreign invaders such as bacteria. However, Gram-negative bacteria have always been the major challenge for macrophages due to the presence of lipopolysaccharides on their outer cell membrane. In the present study, we evaluated the effect of phloretin, a flavonoid commonly found in apple, on the protection of macrophages from Escherichia coli infection. RAW 264.7 cells infected with standard E. coli, or virulent E. coli K1 strain were treated with phloretin in a dose-dependent manner to examine its efficacy in protection of macrophages. Our results revealed that phloretin treatment reduced the production of nitric oxide (NO) and generation of reactive oxygen species along with reducing the secretion of proinflammatory cytokines induced by the E. coli and E. coli K1 strains in a concentration-dependent manner. Additionally, treatment of phloretin downregulated the expression of E. coli-induced major inflammatory markers i.e. cyclooxygenase-2 (COX-2) and hemeoxygenase-1 (HO-1), in a concentration dependent manner. Moreover, the TLR4-mediated NF-κB pathway was activated in E. coli-infected macrophages but was potentially downregulated by phloretin at the transcriptional and translational levels. Collectively, our data suggest that phloretin treatment protects macrophages from infection of virulent E. coli K1 strain by downregulating the TLR4-mediated signaling pathway and inhibiting NO and cytokine production, eventually protecting macrophages from E. coli-induced inflammation.

• Journal of Veterinary Science
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• 제23권2호
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• pp.28.1-28.18
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• 2022

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.

• 대한수의학회지
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• 제43권3호
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• pp.415-421
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• 2003

It is now generally accepted that acupuncture is effective in diarrhea caused by bacterial infection. However, its effect on the intestinal smooth muscle dysfunction is not clear. Therefore, we investigated the effect of acupuncture therapy at Jiao-chao (GV-1) on the intestinal muscle dysfunction in weaning piglets orally infected by Escherichia coli. The animals are divided into four groups; 1) E. coli + no-treatment, 2) E. coli + antibiotic, 3) E. coli + acupuncture, 4) normal group. In the three E. coli infected groups, low frequency electrical field stimulation (EFS, 1 Hz) provoked triphasic responses composed of initial relaxation followed by on-contraction and off-contraction. While in the normal group, EFS (1Hz) induced biphasic responses composed of relaxation during the stimulation and off-contraction. At the high frequency (16Hz) EFS, both on-contraction and off-contraction of the E. coli + antibiotic, E. coli + acupuncture and the normal group were larger than those of the E. coli + no-treatment group. In the non-adrenergic non-cholinergic (NANC) condition, only biphasic responses occurred to EFS in all experimental groups and the off-contraction of E. coli + antibiotic, E. coli + acupuncture and the normal group were larger than those of the E. coli + no-treatment group. The response to carbachol of those three groups was also significantly greater than that of the E. coli + no-treatment group. These results suggest that acupuncture is as effective as antibiotic in the dysfunction of colonic circular muscle caused by E. coli infection. The maintenance of contractile neuromuscular transmission seems to be involved in the mechanism of the acupuncture effects on diarrhea.

• 한국축산식품학회지
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• 제36권2호
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• pp.186-193
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• 2016

This study aimed to inhibit Escherichia coli (E. coli) O157:H7 artificially contaminated in fresh meat using bacteriophage. Among 14 bacteriophages, the highly lytic bacteriophage BPECO19 strain was selected to inhibit E. coli O157:H7 in artificially contaminated meat samples. Bacteriophage BPECO19 significantly reduced E. coli O157:H7 bacterial load in vitro in a multiplicity of infection (MOI)-dependent manner. E. coli O157:H7 was completely inhibited only in 10 min in vitro by the treatment of 10,000 MOI BPECO19. The treatment of BPECO19 at 100,000 MOI completely reduced 5 Log CFU/cm² E. coli O157:H7 bacterial load in beef and pork at 4 and 8h, respectively. In chicken meat, a 4.65 log reduction of E. coli O157:H7 was observed at 4 h by 100,000 MOI. The treatment of single bacteriophage BPECO19 was an effective method to control E. coli O157:H7 in meat samples.

• Journal of Preventive Medicine and Public Health
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• 제36권1호
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• pp.77-84
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• 2003

Objectives : Two related cases of Hemolytic-Uremic Syndrome (HUS) were reported to the Korea National Institute of Health in May, 2001. Shiga toxin 2 genes were detected in both stool samples. We suspected an enterohemorrhagic Escherichia coli (EHEC) infection as the cause of the HUS, and conducted an investigation to find the source of the infection and its route of transmission. Methods : We peformed case investigations on these two related HUS cases, and obtained interviews and rectal swabs form the family members and other close contacts. Additionally, we peformed rectal swabs on the cattle raised by the household of the index patient. Results : We found a 20 month old index patient and a 6 year-old cousin had developed HUS, where there had been a 2 day history of contact with the index, and bacteriological examinations for these two patients revealed, indistinguishably, the same E. coli O171. The grandmother of the index patient was found to be asymptomatic, but E. coli O26 was isolated. We also found a probable case in the mother of the cousin. She reported a history of contact with the index, and developed bloody diarrhea of 3 days duration. The test results for the cattle revealed E. coli O26 in one cow, and E. coli O26 and O55 in another. E. coli O26, which was isolated in both cows and the grandmother of the index, were indistinguishably the same. Conclusions : We found that the E. coli O26 in the grandmother had originated from the cows, and that the E. coli O171 found in the index patient had been transmitted to the cousin through person-to-person contact.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2060-2065
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• 2016

Characteristics of E. coli O157:H7-specific infection bacteriophages (O157 coliphages) and broad-host-range bacteriophages for other E. coli serotypes (broad-host coliphages) were compared. The burst sizes of the two groups ranged from 40 to 176 PFU/infected cell. Distributions of the virulence factors stx1, stx2, ehxA, and saa between the two groups were not differentiated. Broad-host-range coliphages showed lower stability at $70^{\circ}C$, in relation to O157 coliphages. However, O157 coliphages showed high acid and ethanol tolerance by reduction of only 22% and 11% phages, respectively, under pH 3 and 70% ethanol for 1 h exposure. Therefore, these results revealed that the O157 coliphages might be more stable under harsh environments, which might explain their effective infection of the acid-tolerant E. coli O157:H7.

• Childhood Kidney Diseases
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• 제8권2호
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• pp.214-222
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• 2004

목적: 소아 요로감염은 적절한 항생제 치료가 중요하며 항생제의 선택에는 E. coli에 대한 항생제 감수성이 기준이 된다. Extended-spectrum ${\beta}-lactamase(ESBL)$은 E. coli 등 그람음성균에서 분비되어 광범위 항생제 내성을 초래하는 효소로서 주로 병원 감염에서 발생하여 치료를 어렵게 하는 요인으로 알려져 있다 저자들은 지역사회 획득 소아 요로감염에서도 ESBL(+) E. coli가 분리되었기에 ESBL(+) E. coli 요로감염의 특성을 후향적으로 조사하고자 하였다. 방법: 2001년 3월부터 2003년 2월까지 이대목동병원 소아과에 입원한 지역사회 획득 E. coli 요로감염 소아(288명)를 대상으로 ESBL을 검사하였다. 검사 방법은 미량 액체배지 희석법을 이용한 자동화 기계(Vitek GNS 433 card)에서 ESBL이 의심되는 균주에 한해 National Committee for Clinical Laboratory Standard (NCCLS)의 기준에 따라 ESBL을 확인하였다. ESBL의 결과에 따라 ESBL(+) E. coli 요로감염의 발생률을 조사하였고 임상적 특징, 위험요인, 항생제 내성률 및 치료효과 등을 ESBL(-) E. coli 요로감염과 비교 분석하였다. 결과:지역사회 획득 소아 요로감염에서 ESBL(+) E. coli의 발생률은 10.8%(31명)이였고 93.5%(29/31)가 6개월 미만의 영아에서 발생하였다(P<0.01). 임상소견은 ESBL 양성군과 음성군 사이에 유의한 차이가 없었다. ESBL 밭생의 위험인자로 잘 알려진 항생제 사용력, 입원병력 및 요로계 기형과도 무관하였다. ESBL(+) E. coli의 항생제 내성률은 ESBL(-) E. coli 에 비하여 유의하게 높았다(P<0.05). Ceftriaxone 투여 48시간 후의 멸균률은 ceftriaxone에 대한 높은 내성률에도 불구하고 96.8%(30/31)로 높았다. 그러나 6개월 이내의 재발률이 25.8%(9/31)나 되었고 이는 ESBL 음성군의 재발률 6.6%(17/227)에 비하여 유의하게 높았다(P<0.05). 결론: 지역사회 획득 소아 요로감염에서 6개월 미만의 어린 영아는 ESBL(+) E. coli 발생의 새로운 위험요인이므로 이에 대한 역학적 연구가 요구된다. 소아 요로감염에서 경험적으로 사용하는 항생제의 선택에 대한 변화가 필요할 것으로 생각된다.

• Pediatric Infection and Vaccine
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• 제17권2호
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• pp.67-73
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• 2010

목적:소아 UTI에서 non-E. coli UTI 의 빈도를 확인하고 원인균주별(E. coli vs. non-E. coli) 임상양상과 항생제 내성률을 비교하고자 하였다. 방 법: 2008년 9월부터 2009년 8월까지 UTI 입원 환아 중에서 원인균주가 배양 증명된 환아들을 대상으로 하였다. 인구학적 특징, 임상양상, 검사소견, 원인균주와 항생제 내성률을 전향적으로 조사하였다. 결과:전체 84명 중 E. coli UTI 은 63명(75.0%)이었고 non-E. coli UTI은 21명(25.0%)이었다. 성별 연령군에 따라서 non-E. coli의 분포는 차이를 보였다 : 6개월 미만 남아군, 10.5%; 6개월 이상 남아군, 50.0%; 6개월 미만 여아군, 43.7%; 6개월 이상 여아군, 25.0% (P =0.014). E. coli UTI군에 비해, non-E. coli UTI 군에는 입원 전 항생제를 치료받은 환아의 비율이 높았고(P=0.017), 혈뇨가 동반된 환아의 비율은 낮았다(P=0.014). E. coli 보다 non-E. coli는 cefazolin과 cefotaxime, imipenem, TMP/SMX, tetracycline에 대해 높은 내성률을 보였다(P<0.05). 결론:소아 UTI 치료과정에서, 증가 추세의 non-E. coli UTI 빈도와 성별 연령군별 원인균주의 차이, E. coli 보다 높은 non-E. coli의 항생제 내성률은 고려되어야 할 사항이다.