• 대한미생물학회지
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• 제35권1호
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• pp.41-48
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• 2000

Bacteroides fragilis and Escherichia coli, normal colonic inhabitants, are the most frequently isolated bacteria in infected tissues, particularly in intraabdominal abscesses. This study was designed to determine whether enteric bacteria may alter the B. fragilis-induced expression of pro inflammatory cytokines in mouse peritoneal tissue (MPT). After C57BL/6 mice were inoculated with abscess-forming mixture containing B. fragilis in the presence or absence of E. coli, RNA was extracted from MPT. Expression of interleukin (IL)-$1{\alpha}$ and tumor necrosis factor $(TNF){\alpha}$ mRNA was assessed using RT-PCR and standard RNA. Each cytokine protein was also measured by ELISA. The co-inoculation of E. coli into mouse peritoneal cavity advanced the onset of abscess development by B. fragilis infection. When mouse was co-infected with E. coli and B. fragilis intraperitoneally, there was a synergistic increase in the expression of IL-$1{\alpha}$ and $TNF{\alpha}$ mRNA in MPT and this was paralleled by increased cytokine protein secretion. Mixed inoculation of heat-killed E. coli and B. fragilis did not cause a synergistic increase in those cytokine mRNA expression. These results suggest that enteric bacteria may significantly affect proinflammatory cytokine signal produced by host peritoneal cavity in response to B. fragilis infection.

• 대한미생물학회지
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• 제21권4호
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• pp.481-485
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• 1986

Six strains of Bacteroides fragilis group were isolated from clinical specimens, and these isolates were classified by the resistance to bile and kanamycin, and by catalase and indole reaction. Of 6 strains, 4 strains were belonged to B. fragilis and 2 were B. uniformis. Among 6 strains, only 2 of B. fragilis harbored plasmids. But these plasmid showed no correlation with phenotypic expression. There were some differences in susceptibility to 23 ${\beta}$-lactam antibiotics, also, marked susceptibility differences were found between 2 species, so these results may be contributed to the treatment of infection due to this micro-organism and the identification of these species.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.368-377
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• 2020

Enterotoxigenic Bacteroides fragilis (ETBF) is the main pathogen causing severe inflammatory diseases and colorectal cancer. Its biofilm plays a key role in the development of colorectal cancer. The objective of this study was to determine the antagonistic effects of cell-free supernatants (CFS) derived from Clostridium butyricum against the growth and biofilm of ETBF. Our data showed that C. butyricum CFS inhibited the growth of B. fragilis in planktonic culture. In addition, C. butyricum CFS exhibited an antibiofilm effect by inhibiting biofilm development, disassembling preformed biofilms and reducing the metabolic activity of cells in biofilms. Using confocal laser scanning microscopy, we found that C. butyricum CFS significantly suppressed the proteins and extracellular nucleic acids among the basic biofilm components. Furthermore, C. butyricum CFS significantly downregulated the expression of virulence- and efflux pump-related genes including ompA and bmeB3 in B. fragilis. Our findings suggest that C. butyricum can be used as biotherapeutic agent by inhibiting the growth and biofilm of ETBF.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.86-90
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• 2000

We have earlier reported on the cloning and identification of bft-k from an enterotoxigenic strain of Bacteroides fragilis 419, which was isolated from the blood of a Korean patient who suffered from systemic infections [4,5]. The bft-k gene encodes a 397-amino-acids metalloprotease enterotoxin, and the protein has been identified as a new isoform of B. fragilis enterotoxins (BFTs), which are cytopathic to intestinal epithelial cells to induce fluid secretion and tissue damage in ligated intestinal loops [4, 6, 18, 20]. This report describes the cloning and sequencing of the enterotoxin pahogenicity islet of B. fragilis 419 which contains the bft-k gene. the cloned enterotoxin pathogenicity islet was found to have 6,045 bp in length and to contain 120bp direct repeats near its end. In the pathogenicity islet, in addition to the BFR-K, two putative open reading frames (ORFs) were identified; (1) the t-3 gene encoding a 396-amino-acids protein of a putative metalloprotease; (2) the third gene encoding an ORF of a 59-amino-acids protein, whose function has not yet beenn characterized. The expression of the t-3 gene in B. fragilis 419 was verified by western blot analysis.

• Journal of Yeungnam Medical Science
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• 제10권1호
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• pp.135-143
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• 1993

Bacteroides fragilis의 임상 분리균주 45주의 cefaclor, ciprofloxacin, imipenem의 3종 항균제에 대한 감수성 검사를 기존의 한천 평판희석법과 최근 새로이 개발된 E-test (AB Biodisk, Slona, Sweden)법으로, brain heart infusion, Mueller-Hinton, Wilkins Chalgren 한천 배지 3종류를 사용하여 균의 최소발육 억제 농도 (MIC : Minimal Inhibitory Concentration)의 결과를 비교, 관찰하였으며 5종의 quinolone 제제 (ciprofloxacin, enoxacin, norfloxacin, ofloxacin, pefloxacin)에 대한 Bacteroides fragilis group 60주의 시험관내 감수성 검사를 한천 평판 희석법으로 실시하여 다음과 같은 결과를 얻었다. 한천 평판 희석법에서 관찰된 MIC를 기준으로 E-test MIC의 결과를 비교하면 실험균주 90.3%가 한천 평판희석법의 MIC (within${\pm}$1 dilution)와 일치하여 E-test가 B. fragilis의 항균제 감수성 검사법에 한 종류로 유용한 것으로 생각되며 사용된 배지에 따른 감수성상의 양상은 큰 차이를 관찰할 수 없었으며 B. gragilis의 항균제 감수성 검사용 기본 배지로 brain heart infusion배지와 Wilkins Chalgren배지는 적합하나 Mueller-Hinton배지는 부적합 한것으로 나타났다. Bacteroides fragilis group 60주에 대한 5종의 quinolone제제에 대한 감수성상은 ofloxacin을 제외한 약재에 대해 대부분 내성을 띄었으며 균종간의 감수성상의 두드러진 차이는 관찰되지 않았다.

• 대한임상검사과학회지
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• 제47권4호
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• pp.161-167
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• 2015

정상인에서 장내세균은 숙주의 면역이나 영양 흡수를 돕지만, 때로는 기회감염균으로서 그들을 위협하기도 한다. 그 중 절대 혐기성 세균인 Bacteroides fragilis는 분비되는 장독소(enterotoxin)인 Bacteroides fragilis toxin (BFT)의 유무에 따라 non-enterotoxigenic B. fragilis (NTBF)와 enterotoxigenic B. fragilis (ETBF)로 나뉜다. ETBF는 가축 및 사람에서 설사 질환 및 대장 질환을 유발한다 그러나 때때로 ETBF를 가지고 있으나 증상이 없는 사람도 존재한다. ETBF는 염증성 설사 질환, 여행자 설사 환자의 대변에서 검출되어 주목 받고 있다. 또한, 몇몇 연구를 통해 inflammatory bowel disease (IBD)나 대장염 및 대장암 환자에서 ETBF가 증가한다는 것이 밝혀졌다. 일반 C57BL/6 마우스 및 germ-free 마우스, multiple intestinal neoplasia (Min) 마우스, 토끼, Mongolian gerbil 등 여러 동물 모델에서 ETBF가 IBD나 대장염, 대장암을 유발 또는 촉진한다는 것이 발표되었다. ETBF의 유일한 병원성 인자인 BFT는 E-cadherin의 분절을 유도하여 장상피 세포의 투과성을 높인다. 이어서 ${\beta}$-catenin 신호전달계가 활성화하여 장상피세포의 증식이 증가한다. 또한 ETBF의 감염은 일반 마우스에서 급성이나 만성의 대장염을 일으키고 Min 마우스에서 종양 형성을 촉진한다. 이는 Stat3에 의존한 $T_H17$ 면역반응의 활성화를 통해 일어난다. 현재 ETBF의 검출 방법에는 크게 BFT toxin assay와 몇 가지 PCR 방법이 있다. 최근 real-time PCR과 같은 분자진단학적 기법의 발달로 일반적인 PCR보다 더 정확한 ETBF의 검출이 가능하게 되었다. 이것을 이용하여 앞으로 실제 임상에서 ETBF와 대장염 및 대장암의 발달 관계에 대한 심도 깊은 연구가 이뤄질 것으로 본다.

• Journal of Microbiology and Biotechnology
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• 제7권3호
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• pp.174-179
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• 1997

In order to investigate effect of glucooligosaccharide (GOS) prepared by extrusion process as a bifidogenic factor, cultivation of Bifidobacterium sp., Bacteroides fragilis and Clostridium perfringens was done and analyzed. B. fragilis and C. perfringens were able to utilize only 16% and 11% of the oligosaccharides in GOS, respectively, whilst Bifidobacterium sp. FBD-22 could utilize 38%. Especially, many kinds of oligo saccharides in GOS were able to be utilized selectively only by Bifidobacterium sp.. In case that GOS, as a carbon source, was used in the co-cultivation by Bifidobacterium sp., B. fragilis and C. perfringens, growth of Bifidobacterium sp. was not influenced by the existence of B. fragilis and C. perfringens. Bifidobacterium sp. showed advantage on carbon source competition for GOS with B. fragilis. Acetic acid, antimicrobial agent in the intestine, was produced two times more from GOS than glucose in co-cultures of three strains. Therefore, it is suggested that GOS can be a potent bifidogenic factor which proliferates the population of Bifidobacterium sp. and may finally improve the intestinal environments of human.

• 대한임상검사과학회지
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• 제48권2호
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• pp.82-87
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• 2016

Enterotoxigenic Bacteroides fragilis (ETBF)는 병독소 인자로 알려진 장독소를 생성하는 균종이다. B. fragilis enterotoxin (BFT)은 bft-1, bft-2 및 bft-3 세 개의 유전자 아형들이 밝혀졌다. 본 연구에서는 임상 검체에서 분리된 B. fragilis에서 bft 유전자의 유무와 BFT 음성 및 양성 균주의 항균제 내성을 조사하였다. 국내의 한 대학병원에서 8년간(2006~2013년) 장외 검체에서 분리된 B. fragilis는 총 537주이었다. 다중중합연쇄반응으로 시험하여 bft 유전자 아형을 확인하였다. BFT 음성 74주와 양성 33주를 포함한 B. fragilis 107주의 항균제 감수성은 CLSI 한천희석법으로 시험하였다. 임상 검체에서 분리된 B. fragilis의 bft 유전자 검출율은 30% 이었고, 이 중 혈액과 혈액 외 장외 검체 분리주에서는 각각 33%, 29% 이었다. ETBF 중에서 가장 흔한 아형은 bft-1 이었고, 그 다음은 bft-2, bft-3 순이었다(bft-1: 77%, bft-2: 14%, bft-3: 9%). BFT-음성과 양성 균주의 내성률은 일부 항균제에 대해서 차이가 있었다(BFT-음성 균주: piperacillin-tazobactam 3%, cefoxitin 5%, imipenem 1%, clindamycin 38%; BFT-양성 균주: piperacillin-tazobactam 3%, cefoxitin 6%, imipenem 3%, clindamycin 42%). BFT-음성 및 BFT-양성 균주 모두는 chloramphenicol과 metronidazole에 대한 내성은 없었다. 결론적으로, 혈액 분리주에서의 ETBF 검출율은 혈액 외 장외 검체 분리주에서와 비슷하였고, 가장 흔한 유전자 아형은 bft-1 이었다. 항균제 내성은 BFT 양성 균주가 음성 균주보다 대체로 높았으나 통계학적으로 유의한 차이는 없었다.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.91-94
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• 1993

A 3-isopropylmalate dehydrogenase (3-IPMD) gene was cloned from Kluyveromyces fragilis. pJK104 could complement Escherichia coli leuB and Saccharomyces cerevisiae leu2 auxotrophs. The coding region was subcloned and the nucleotide sequence was determined. A 1.8 Kb EcoRI/SphI fragment of pJK104 subcloned in pUC18 could still complement the leuB mutation. An open reading frame of 1164 bp that corresponds to a polypeptide of 387 amino acids was found in the cloned fragment. The homology between the 3-isopropylmalate dehydrogenase of S. cerevisiae and that of K. fragilis was 68.13％ in nucleotides.

• Journal of Applied Biological Chemistry
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• 제43권1호
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• pp.54-58
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• 2000

Methanol extracts of 27 Brazilian plant samples and 10 oriental medicinal plant samples (27 families), using spectrophotometric and paper disc agar diffusion methods under anaerobic conditions, were tested in vitro for their growth-inhibiting activities against Bifidobacterium longum, Bifidobacterium bifidum, Bifidobacterium adolescentis, Clostridium perfringens, and Bacteroides fragilis. The responses varied with bacterial strains, plant species, and tissues sampled. In a test with B. longum and B. bifidum(20 mg/disc), extracts of Acanthopanax sessilifolinus stem bark and Ampelozizyphus amazonicus leaves strongly inhibited the growth of B. longum, whereas other plant samples did not inhibit any intestinal bacteria tested. At 5 mg/disc, adding extracts of Aralia eleta, Euterpe oleracea, and Syzygium guineense to the media strongly inhibited the growth of C. perfringens and B. fragilis without growth inhibition of B. adolescentis, B. longum, and B. bifidum. Extracts of Jacaranda mimosifolia and Ulmus paraifolia significantly inhibited the growth of C. perfringens and B. fragilis as well as B. adolescentis. These results may be indications of at least one of the pharmacological actions of the five Brazilian plants but not oriental medicinal plants tested.