• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.722-725
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• 1999

Filamentation-suppressed recombinant Escherichia coli strain harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes and the E. coli ftsZ gene was constructed and cultivated for the production of poly(3-hydroxybutyrate) [P(3HB)] with high concentration and high content. By the pH-stat fed-batch culture of this recombinant E. coli strain XL1-Blue(pJC5), the final cell concentration and P(3HB) concentration obtained in 44.25h were 172.2g cell dry weight/l and 141.9g P(3HB)/l, respectively, resulting in productivity of 3.21g P(3HB)/l-h. More importantly, the P(3HB) content obtained was 82.4 wt %, which was significantly higher than that obtained with the recombinant E. coli harboring only the PHA biosynthesis genes.

• 미생물학회지
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• 제45권2호
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• pp.163-169
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• 2009

본 논문은 부산소재 하수처리장 중계시설인 민락오수처리장의 하수에서 광범위 베타 락탐 분해효소(extendedspectrum $\beta$-lactamase, ESBL) 생성균주를 분리 동정하고 이들이 생성한 ESBL 유형을 조사하였다. 민락오수처리장은 부산 남구 수영구의 민락동 일대에 밀집한 횟집의 하수를 모아서 남구 용호동에 있는 하수종말처리장으로 중계시키는 시설이다. 2009 년 1 월 하수 검체로부터 항균제 이중 디스크 확산 시험(double disk synergy test)에 양성반응을 나타낸 19 균주를 1차 시험균주로 선택하였다. 인돌생성 시험 methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase 및 당 발효능 생화학 시험을 통하여 Klebsiella pneumoniae (3 균주)와 Escherichia coli (16 균주)가 동정되었다. 이 균들을 공여균주로, Escherichia coli J53 (sodium $azide^r$)를 피전달균주로 하여 접합시험을 실시하여 plasmid로 매개된 4 균주 접합체를 얻었다. 이들로부터 plasmid를 추출하여 PCR로 유전자 증폭을 시켜 유전자를 분석하고 등전점을 조사한 결과 Klebsiella pneumoniae에서 생성된 ESBL 유형은 모두 SHV-12 (3 균주)였고, Escherichia coli에서 생성된 ESBL 유형은 SHV-12/TEM-1 (1 균주)였다.

• 대한의생명과학회지
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• 제17권1호
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• pp.7-12
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• 2011

Free-living amoebae ingest several kinds of bacteria. In other words, the bacteria can survive within free-living amoeba. To determine how Escherichia coli K1 isolate causing neonatal encephalitis and non-pathogenic K12 interact with free-living amoebae, e.g., Acanthamoeba castellanii (T1), A. astronyxis (T7), Naegleria fowleri, association, invasion and survival assays were performed. To understand pathogenicity of free-living amoebae, in vitro cytotoxicity assay were performed using murine macrophages. T1 destroyed macrophages about 64% but T7 did very few target cells. On the other hand, N. fowleri which needed other growth conditions rather than Acanthamoeba destroyed more than T1 as shown by lactate dehydrogenase (LDH) release assay. In association assays for E. coli binding to amoebae, the T7 exhibited significantly higher association with E. coli, compared with the T1 isolates (P<0.01). Interestingly, N. fowleri exhibited similar percentages of association as T1. Once E. coli bacteria attach or associate with free-living amoeba, they can penetrate into the amoebae. In invasion assays, the K1 (0.67%) within T1 was observed compared with K12 (0%). E. coli K1 and K12 exhibited high association with N. fowleri and bacterial CFU. To determine the fate of E. coli in long-term survival within free-living amoebae, intracellular survival assays were performed by incubating E. coli with free-living amoebae in PBS for 24 h. Intracellular E. coli K1 within T1 (2.5%) and T7 (1.8%) were recovered and grown, while K12 were not found. N. fowleri was not invaded and here it was not recovered.

• 대한수의학회지
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• 제21권2호
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• pp.87-91
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• 1981

OK serogroups of 268 cultures of Escherichia coli isolated from piglets with colibacillary diarrhea were determined by the use of the simplified routine diagnostic procedures of Sojka. The results obtained are summarised as follows: 1. Of 268 cultures of Escherichia coli tested, 190 cultures were classified into 15 OK groups and the remaining 78(29.1%) were untypable. 2. The most frequently isolated enteropathogenic E. coli in order of prevalence were 0157 : K 'Vl7' (14.2%), 0149 : K91, K88a, c (13.7%), 064 : K 'V142' (11.6%), 08 : K87, K88a, b (10.5%) and O141 : K85a, b, K88a, b (7.9%).

• 대한임상검사과학회지
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• 제41권2호
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• pp.47-51
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• 2009

A case of recurrent urinary tract infection by cysteine-requiring Escherichia coli in a 5-years-old child with congenital vesicoureteral reflux is described. This bacterium was not grown on MacConkey agar plate for overnight culture, and after 48hrs, tiny colonies were observed. These colonies were not identified by VITEK2 and Walkaway 96i without cysteine supplementation. The isolate was susceptible for cefotetan, ciprofloxacin and imipenem, and resistant for piperacillin/tazobactam, cephalothin, cefotaxime, ceftazidime, amikacin, gentamicin, and tobramycin.

• 대한수의학회지
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• 제17권1호
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• pp.5-8
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• 1977

One hundred and fifty seven Escherichia coli strains isolated from 18 cattle (9 dairy cattle received penicillin, streptomycin (SM) or sulfadimethoxine for treatment of diseases and 9 Korean native cattle not received antibiotics) were studied for the drug resistance and distribution of R factors. Of 88 E. coli strains isolated from cattle not received antibiotics, only 1 strain was resistant to SM, but about 46 per cent of 69 E. coli strains isolated from cattle received antibiotics were resistant to SM, tetracycline (TC), ampicillin (AP), kanamycin (KM), chloramphenicol (CM), and sulfisomidine (Su), alone or in combination thereof. Of resistant strains, about 72% were resistant to three or more antibiotics, but 28% were found to singly resistant. The most frequent resistant pattern was triple resistance to AP, KM and Su (37.6%), and quadruple one to SM, TC, CM and Su (12.5%). About 28% of resistant strains carried R factors which were transferable to E. coli ML 1410 $NA^r$ by conjugation.

• Pediatric Infection and Vaccine
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• 제4권1호
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• pp.73-78
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• 1997

목 적 : Escherichia coli (E. coli) O157은 설사, 출혈성대장염 등을 일으키며, 드물게 용혈성 요독증후군까지 일으키는 세균이다. 미국이나 유럽에서는 세균성설사의 2~3번째로 흔한 원인균이다. 우리나라는 이 세균감염이 거의 없는것으로 알려져 왔으나, 우리나라도 점차 햄버거와 같은 간이음식의 섭취가 늘어나, 이 세균감염이 생겼을 가능성이 있을 것으로 사료되어, 향후 이 세균에 대한 통상적인 변배양 검사의 필요성 여부를 알아보고자 하였다. 방 법 : 1996년 3월부터 1997년 2월까지 6개월 이상된 소아설사 환아의 변배양 검체를 대상으로 하였다. Sorbitol-MacConkey 한천에 배양한 후 형성된 집락 중 무색 집락을 대상으로 E. coli로 동정된 것을 E. coli O157 라텍스 응집검사를 실시하여 응집이 되면 양성으로 판독하였다. 결 과 : 총 317 검체중 11월에 1 검체 (0.3%)에서 Shiga 독소를 생성하지 않는 E. coli O157:NM이 분리되었다. 7세 남아로 2일간의 복통과 1일간의 설사 및 구토를 주소로 입원 한 후 특별한 치료없이 2일후 증상이 호전되어 퇴원하였다. 결 론 : 검사된 모든 대변 검체중 한 검체 (0.3%)만이 E. coli O157이 분리되었으나 Shiga 독소를 생성하지 않는 군주였다. 따라서 이 세균의 분리를 위한 통상적인 변배양 검사는 아직 불필요한 것으로 사료되었다.

• 대한수의학회지
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• 제28권1호
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• pp.59-65
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• 1988

This paper deals with the 0 groups of citrate utilizing variants of Escherichia coli ($Cit^+$ E. coli) isolated from cattle, the production of colicin, hemolysin, K99 antigen, heat stable enterotoxin, and the isolation of plasmid DNA. Among 42 $Cit^+$ E. coli, 12 strains were 020, 9 strains 08, 5 strains 045, 3 strains 0115, 1 strain 064, 1 strain 0139 and remaining strains(11) were untypable. Thirty-nine(81.3%) out of 48 $Cit^+$ E. coli were produced colicin and 13(27.0%) were produced hemolysin. Of 12 $Cit^+$ E. coli bearing K99 antigen, 6(50.0%) were produced heat stable enterotoxin. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmids varied from 1 to 7 in 10 $Cit^+$ E. coli. It's molecular weight ranged from 2 to 50 Mdalton, and 50 Mdalton plasmid was commonly existed in all strains.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.529.1-529
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• 1986

For isolation of the CMCase gene of the alkalophilic Bacillus sp. strain N-4 to analyze their genetic information for the multicomponents of the cellulase, Bscherichia coli K12 and plasmid DNA pBR322 was used as host-vector system. After the digestion of purified chromosomal DNA and plasmid DNA pBR322 with HindIII, these were ligated. The ligated DND were transformed into Escherichia coli, and recombinant plasmid 107 carried the gene coding for CMCase was constructed. The CMCase produced by Escherichia coli cells containing plasmid DNA pYBC107 was found in the cells as intracellular enzyme and nearly 60% of the total CMCase activity was localized in cellular fraction. Also, the optimum pH for the reaction of CMCase produced by Escherichia coli was appeared at pH .8.0 and the enzyme was stable between pH 7.0 and pH 8.0.

• 한국축산식품학회지
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• 제38권4호
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• pp.829-834
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• 2018

The objective of this study was to determine the minimum enrichment time for different types of food matrix (pork, beef, and fresh-cut lettuce) in an effort to improve Escherichia coli detection efficiency. Fresh pork (20 g), beef (20 g), and fresh-cut lettuce (20 g) were inoculated at 1, 2, and 3 Log CFU/g of Escherichia coli. Samples were enriched in filter bags for 3 or 5 h at $44.5^{\circ}C$, depending on sample type. E. coli cell counts in the samples were enriched in E. coli (EC) broth at 3 or 5 h. One milliliter of the enriched culture medium was used for DNA extraction, and PCR assays were performed using primers specific for uidA gene. To detect E. coli (uidA) in the samples, a 3-4 Log CFU/mL cell concentration was required. However, E. coli was detected at 1 Log CFU/g in fresh pork, beef, and fresh-cut lettuce after 5, 5, and 3-h enrichment, respectively. In conclusion, 5-h enrichment for fresh meats and 3-h enrichment for fresh-cut lettuce in EC broth at $44.5^{\circ}C$, and PCR analysis using uidA gene-specific primers were appropriate to detect E. coli rapidly in food samples.