• Journal of Microbiology
• /
• 제45권1호
• /
• 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
• /
• 제27권4호
• /
• 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.

• 한국환경보건학회지
• /
• 제20권2호
• /
• pp.90-98
• /
• 1994

전남지역에서 사육하고 있는 젖소 767두 중 유방염으로 의심되는 405두에서 원인균을 분리하여 유병률, 계절별 분리균의 분포, 항균 요법제에 대한 감수성 검사 등을 실시하였다. 유방염의 유병률을 살펴보면, 총 767두 중애서 259두(33.8%)이었고, 분방별로는 총 3,068분방 중에서 568분방(18.5%)이었으며, 계절별로는 8원(17.6%), 9월(12.7%), 4월(11.2%) 등의 순으로 나타났고 체세포 숫자별로는 평균 105.9X10$^4$ $\pm$ 79.5X10$^4$이었다. 원인균의 월별 분리빈도분포를 살펴보면, 1월에는 Staphylococcus sp. & Escherichia coli(33.3%), 2월 Staphylococcus sp.(71.4%), 3월 Streptococcus sp.(31.6%), 4월 Streptococcus sp.(41.4%), 5월 Escherichia coli(35.7%), 6월 Staphylococcus aureus(26.9%), 7월 Salmonella sp.(25.9%), 8월 Escherichia coli(20.5%), 9월 Escherichia coli & Pseudomonas sp.(21.2%), 10월 Klebsiella sp.(29.6%), 11월 Salmonella sp.(31.6%), 12월 Streptococcus sp.(37.5%) 등이 가장 높았다. 체세포 숫자별 원인균의 분리빈도분포를 살펴보면, Staphylococcus sp.(251 X 10$^4$ $\pm$ 300X10$^4$ 35.7%)을 제외하고는 일반적으로 50 X 10$^4$ $\pm$ 100X10$^4$이 가장 높았다. 항균요법제에 대한 감수성은 일반적으로 trimethoprim/sulfamethoxazole은 Streptococcus Sp, Staphylococcus aureus, Staphylococcus sp., Klebsiella sp.에 높았으며 gentamycin은 Staphylococcus sp., Escherichia coli, Klebsiella Sp, Proteus sp., Pseudomonas sp., Salmonella sp.에 높았다.

• 한국미생물·생명공학회지
• /
• 제31권1호
• /
• 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.

• 한국임상수의학회지
• /
• 제24권4호
• /
• 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
• /
• 제32권5호
• /
• 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.

• 대한수의학회지
• /
• 제50권3호
• /
• 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.

• 한국식품위생안전성학회지
• /
• 제31권6호
• /
• pp.393-398
• /
• 2016

본 연구에서는 선택배지와 건조필름을 이용하여 신선편이 엽채류 3종(양상추, 양배추, 어린잎채소)에서 병원성 E. coli를 분리하였고, 의심집락 동정을 위해 생화학적 분석법을 사용하여 동정한 후 결과를 비교 분석하였다. 양상추 20 g, 양배추 20 g, 어린잎채소 10 g에 병원성 E. coli 혼합 균액(Enterohemorrhagic E. coli NCCP11142, Enterotoxigenic E. coli NCCP14037, Enteropathogenic E. coli NCCP14038, Enteroaggregative E. coli NCCP14039, Enteropathogenic E. coli NCCP15661)을 최종농도가 1, 2, 3 log CFU/g이 되도록 접종하였고, BPW (80~90 ml)을 넣은 후 60초 동안 균질화하여 분석하였다. 연구결과, 모든 시료에서 건조필름 시험 양성, 양상추 시료 일부(최종농도 3 log CFU/g 접종시료)를 제외한 모든 시료에서 증균배양법을 이용한 정성시험결과가 음성으로 나타났다. 증균배양과 건조필름 시험을 통해 분리한 병원성 E. coli를 이용하여 생화학적 분석을 실시한 결과, 양상추에서 분리한 병원성 E. coli의 경우, API 20E 100% (44/44), Microgen GNA 100% (44/44), Food System 66.7% (10/15)의 동정률이 나타났다. 양배추의 경우, API 20E 64.7% (22/34), Microgen GNA 50% (16/32), Food System 60% (9/15), 어린잎채소의 경우, API 20E 65.1% (28/43), Microgen GNA 62.3% (27/43), Food System 53.3% (8/15)가 병원성 E. coli로 동정되었다. 본 연구의 결과는 신선편이 엽채류에 대한 병원성 E. coli 검출법 선택에 유용하게 이용될 것으로 판단된다.

• Journal of Dairy Science and Biotechnology
• /
• 제15권1호
• /
• pp.11-20
• /
• 1997

병원성 대장균(炳原性 大腸菌) O157:H7에 대(對)한 유산균 발효유(乳酸菌 醱酵乳)의 발육억제효과(發育抑制效果)에 관한 실험(實驗)을 시도(試圖)하여, 標準 유산균(標準 乳酸菌)의 균주(菌株)로는 Lactobacillus bulgaricus, L. acidophilus 그리고 L. cormatus를 이용하여 BL broth에 각각(各各)의 유산균주(乳酸菌株)와 대장균(大腸菌) O157:H7의 수(數)(10$^5$/ml)를 동일(同一)하게 접종(接種)하고 시간별(時間別)로 관찰(觀察)한바 배양(培養)된지 대략(大略) 18시간 전후(時間 前後)하여 대장균(大腸菌)의 발육(發育)이 억제(抑制)되었고, 시판유산균 발효유(市販乳酸菌 醱酵乳) 3종(種)에 접종(接種)된 병원성 대장균(炳原性 大腸菌) O157:H7 (10$^8$/ml)은 접종(接種)된지 대략(大略) 140${\sim}$200분내(分內)에 발육(發育)이 억제(抑制)되었음이 관찰(觀察)되었다. 이상(以上)의 결과(結果)를 미루어 보아 유산균 발효유(乳酸菌 醱酵乳)는 병원성 대장균(炳原性 大腸菌)O157:H7에 대(對)하여 생성(生成)된 산(酸)에 의(依)한 억제작용(抑制作用)과 일부 미지(一部 未知)의 항균물질(抗菌物質)에 依(依)한 부가작용(附加作用)이 있었을 것으로 믿어 계속적(繼續的)인 추구(追究)가 요망(要望)된다.

• Journal of Microbiology and Biotechnology
• /
• 제14권5호
• /
• 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.