• Pediatric Infection and Vaccine
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• 제23권3호
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• pp.223-228
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• 2016

국내 Shigella 감염은 대부분 Shigella sonnei 에 의해 발생하나 드물게 Shigella flexneri 에 의한 집단 감염이 보고되고 있다. 항생제 사용률이 높은 국내에서 extended-spectrum ${\beta}-lactamase$ (ESBL) 생성 S. sonnei 감염에 대한 보고는 있었으나 ESBL을 생성하는 S. flexneri 에 대한 예는 지금까지 없었다. 저자들은 국내 한 어린이집에 다니는 소아 2명에게서 CTX-M-14 유형 ESBL 생성 S. flexneri type 2a 감염 증례를 경험하였으며 이는 국내에서 ESBL을 생성하는 S. flexneri 감염의 첫 증례이다. 앞으로 국내에서도 Shigella 감염 시 ESBL 균주의 가능성을 고려하고 적극적인 역학조사와 경험적 항생제 투여에 대한 신중한 선택이 필요할 수 있을 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1616-1621
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• 2007

We have established a SYBR Green-based realtime PCR method using AnyDirect solution, which enhances PCR from whole blood, for direct amplification of the virA gene of Shigella flexneri and the invA gene of Salmonella typhimurium from human feces without prior DNA purification. When we compared the efficiency of conventional or realtime PCR amplification of the virA and invA genes from the supernatant of boiled feces supplemented with S. flexneri and S. typhimurium in the presence or absence of AnyDirect solution, amplification products were detected only in reactions to which AnyDirect solution had been added. The detection limit of real-time PCR was $1{\times}10^4\;CFU/g$ feces for S. flexneri and $2{\times}10^4\;CFU/g$ feces for S. typhimurium; this sensitivity level was comparable to other studies. Our real-time PCR assay with AnyDirect solution is simple, rapid, sensitive, and specific, and allows simultaneous detection of S. flexneri and S. typhimurium directly from fecal samples without prior DNA purification.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.621-629
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• 2021

Shigella flexneri is a facultative intracellular pathogen that causes bacillary dysentery in humans. Infection with S. flexneri can result in more than a million deaths yearly and most of the victims are children in developing countries. Therefore, identifying novel and unique drug targets against this pathogen is instrumental to overcome the problem of drug resistance to the antibiotics given to patients as the current therapy. In this study, a comparative analysis of the metabolic pathways of the host and pathogen was performed to identify this pathogen's essential enzymes for the survival and propose potential drug targets. First, we extracted the metabolic pathways of the host, Homo sapiens, and pathogen, S. flexneri, from the KEGG database. Next, we manually compared the pathways to categorize those that were exclusive to the pathogen. Further, all enzymes for the 26 unique pathways were extracted and submitted to the Geptop tool to identify essential enzymes for further screening in determining the feasibility of the therapeutic targets that were predicted and analyzed using PPI network analysis, subcellular localization, druggability testing, gene ontology and epitope mapping. Using these various criteria, we narrowed it down to prioritize 5 novel drug targets against S. flexneri and one vaccine drug targets against all strains of Shigella. Hence, we suggest the identified enzymes as the best putative drug targets for the effective treatment of S. flexneri.

• 한국자기공명학회논문지
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• 제19권1호
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• pp.36-41
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• 2015

The causative agent of shigellosis, Shigella flexneri, is a Gram-negative anaerobic bacterial pathogen that causes one of the most infectious bacterial dysenteries in humans. It originates infection by invading cells of the colonic epithelium using a type III secretion system. Despite S. flexneri is closely linked with the human disease, structural study is very deficient. Here, we have initiated NMR study of SF1002 which is the uncharacterized protein from S. flexneri strain 5a M90T. Based on a series of triple resonance spectra, sequence-specific assignments of the backbone amide resonances of SF1002 could be completed. This NMR study would contribute to the structural genomics of S.flexneri.

• 대한미생물학회지
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• 제22권1호
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• pp.35-53
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• 1987

Multiply resistant Shigella strains isolated in Taegu area were subjected for the characterization of R plasmids. All strains isolated in 1984 and 1985 were susceptible to gentamicin, amikacin, and cephalothin, and most strains were susceptible to kanamycin (Km) and rifampin by agar dilution antimicrobial susceptibility test. The resistance frequency of S. flexneri against ampicillin (Ap) was higher than that of S. sonnei. The strains resistant to sulfisomidine (Su) and trimethoprim (Tp) were found at higher frequency in S. sonnei than in S. flexneri. The most prevalent resistance pattern of S. flexneri was chloramphenicol (Cm) tetracycline (Tc) streptomycin (Sm) Ap, followed by the pattern of CmTcSmSuApTp, CmTcSmSuApTp nalidixic acid, and CmTcSmSuAp in the decreasing order. The antibiogram of CmTcSmSuTp was found to be the most frequent pattern in S. sonnei. The ratio of conjugal transfer of S. flexneri was 47% and 75% of S. sonnei. The average number of plasmid harboring in Shigella was 4 and the size of plasmid ranged 1.3 to 134 megadalton (Mdal). Most S. flexneri carried plasmids of 2 to 3 Mdal and S. sonnei carried those of 3 to 4 Mdal size. The sizes of conjugative plasmids ranged 40-90 Mdal. The incompatibility group (Inc) F II plasmids (54-59 Mdal) were most frequent and rare Inc B plasmids (60 Mdal) of isolates in 1979 and 1980 and Inc FI (87 Mdal) of 1983 isolates were able to be classified by the colony test with standard reference plasmids. The R plasmids of known Inc group were tested for the restriction endonuclease analysis. The pattern of plasmids digested by EcoRl were apparently different by the Inc group but there was no significant difference between species or by the resistance patterns. Nonconjugative plasmids and their phenotypes were identified by transformation test. The transformants were resistant to less than two drugs. Colicin producing transformants carried the Col plasmid of 3.7 or 3.9 Mdal size. $Ap^r$ plasmids derived from S. sonnei were found to be mobilized by transfer factor RT641 to E. coli #CS100. $Ap^r$ plasm ids of same size shared by S. flexneri, S. sonnei, and E. coli were digested with Pstl. All of them showed two restriction fragments of 2.8 kilobase(kb) and 0.7kb. Other plasmids ($Sm^r\;Su^r$) derived from S. flexneri, S. boydii, and S. sonnei were digested with Pstl and they showed same restriction fragment patterns of 3.1kb and 2.9kb. The plasmid profiles of three strains of S. sonnei producing colicin and showing same resistance pattern of CmTcSmSuApTpKm appeared to be similar. Restriction patterns by EcoRl and the behavior of plasmids in conjugation or transformation process were also similar between those plasmids. The restriction patterns were significantly different between the plasmids of Inc FI group and those of unclassified Inc group.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1457-1462
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• 2010

Three types of serotypically atypical Shigella flexneri isolates were collected between 2007 and 2008 from Korean patients at the Korea National Institute of Health (NIH). These atypical isolates were characterized and compared with serologically typical S. flexneri. The first grouping of 11 atypical isolates displayed agglutination only with polyB antiserum and exhibited no reaction with any typing or grouping sera (PolyB:un). The second group of 3 isolates displayed reactions with typing sera IV, but also did not bind with any grouping sera (IV:un). The third group of 14 isolates exhibited a plural agglutination pattern, reacting with typing sera II, and two grouping sera (II:(3)4,7(8)). Amongst these atypical isolates, isolates belonging to IV:un and II:(3)4,7(8) exhibited greater antibiotic resistance, in particular to ampicillin, streptomycin, and trimethoprim-sulfamethoxazole, than typical S. flexneri strains. Furthermore, all II:(3)4,7(8) strains harbored integrons. This study suggests that these multiple antibiotic-resistant atypical S. flexneri are new subserotypes of S. flexneri that await further serological classification.

• 한국식품조리과학회지
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• 제21권3호
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• pp.319-325
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• 2005

본 연구에서는 식중독 유발세균에 대한 항균활성이 우수한 천연 항균성 물질을 검색하기 위해 예로부터 민간과 한방에서 널리 이용되어 온 연교를 각종 유기용매로 추출하여 식중독 유발세균에 대한 항균활성을 조사해 보았다. 연교를 petroleum ether, chloroform, ethly acetate, methanol를 이용하여 실온에서 각각 용매별로 계통 분획하고, 열수추출물을 얻은 후, 9종의 식중독 유발세균 (Staphylococcus aureus, Staphylococcus epidermidis, Salmonella paratyphimurium, Shigella flexneri, Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Pseudomonas aeruginosa, Shigella sonnei)에 대하여 항균효과를 조사하였다. 연교 추출물의 농도별 항균 활성 검색에서는 연교의 열수 추출물이 가장 큰 항균 효과를 보였으며 Staphylococcus epidermidis와 Shigella flexneri가 가장 민감하게 반응하는 균주였다. 연교의 열수 추출물과 느릅나무의 methanol 추출물을 혼합하여 항균력을 측정해 본 결과 두 추출물을 섞어 첨가했을 경우가 단독으로 사용했을 시 보다 상승효과를 나타내었다. 또한 연교의 열수 추출물이 식중독 유발세균의 성장에 미치는 효과를 검정하기 위해 Staphylococcus epidermidis 및 Shigella flexneri의 배양액에 연교의 열수 추출물을 각각 10,000 ppm 농도로 첨가했을 시, Staphylococcus epidermidis의 생육이 12시간 이상까지 억제됨을 관찰할 수 있었고, Shigella flexneri의 생육도 24시간까지 지연시킬 수 있었다. 이상의 결과 연교의 열수 추출물은 S. epidermidis와 Shigella flexneri의 성장을 효과적으로 억제시킴을 알 수 있었다.

• 한국식품영양과학회지
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• 제34권10호
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• pp.1606-1610
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• 2005

각종 식중독의 원인균으로 중요시되는 11종의 균주에 대해서 황금탕 및 황금 추출물의 항균력을 검토한 결과, 황금탕 추출물은 Staphylococcus aureus, Bacillus cereus, Shigella sonnei, Shigella flexneri, Salmonella Typhimurium, Salmonella Enteritidis, Vibrio parahaemolyticus, Escherichia coli O111 및 Escherichia coli O126에서 항균력을 나타내었고, 황금 추출물은 Staphyoccus aureus, Bacillus cereus, Shigella sonnei, Shigella flexneri, Salmonella Typhimurium, Salmonella Enteritidis, Vibrio parahaemolyticus, Escherichia coli O111, Escherichia coli O126 및 Escherichia coli O157에서 항균력을 나타내었다. Listeria monocytogenes에 대해서는 황금탕 및 황금 추출물 모두 항균력이 없었고, Escherichia coli O157에 대해서는 황금탕 추출물은 항균력이 없었으나, 황금 추출물은 항균력을 나타내었다. 황금탕 추출물의 최소저해농도는Staphyloccus aureus와 Bacillus cereus에서 40 mg/mL, Shigella flexneri 와 Salmonella Enteritidis에서 100 mg/mL이었고, 황금 추출물의 최소저해농도는 Bacillus cereus에서 10 mg/mL, Staphylococcus aureus, Shigella flexneri 및 Salmonella Enteritidis에서 20 mg/mL이었으며, 황금탕 및 황금 추출물 모두 Staphyloccus aureus와 Bacillus cereus에 대해 48시간까지 배양하는 동안 최소저해농도 이상에서는 균이 거의 생육하지 못하였다. 이상에서 황금탕 추출물보다는 황금 추출물의 항균력이 더 강하며, 황금탕 추출물의 식중독 세균들에 대한 항균력은 황금에 의한 것으로 생각된다. 또한, 항균력이 확인된 세균으로 인한 각종 식중독에 황금탕의 사용 가능성을 고려할 만하며, 황금 추출물에 대한 천연 식품 보존료로서의 이용 가능성을 검토할 가치가 있다고 사료된다.

• 동의생리병리학회지
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• 제16권6호
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• pp.1184-1189
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• 2002

Allii sativi Bulbus(garlic) have been shown to possess medicinal value, in particular, antimicrobial activity. In this study, we compared the efficacy on some pathogenic bacteria and fungus among several different extracts(water, hexane, ethyl acetate, methanol, chloroform) of Allii sativi Bulbus. Animal pathogenic bacteria and fungus(S. gallinarium: KCTC 2441, S. flexneri: KCTC 2361, E. cloacae: KCTC 2006, K. pneumonia: KCTC 2208, C. albicans: KCTC 1940) were used to test by measurement of minimum inhibitory concentrations(MIC) and disc diffusion. Allii sativi Bulbus were cut and mixed with water at 37℃ about 24 h and filtered, and several different solvents(hexane, chloroform, ethyl acetate, methanol) were respectively added to separate the fraction of each solvent. The antimicrobial(bacteriocidal) and antifungal effect were apparently shown from water extract, hexane and ethyl acetate extract against using strains(Staphylococcus gallinarium, Shigella flexneri, Enterobacter doacae, Klebsiella pneumonia, Candida albicans). Especially, the water extract showed the superior efficacy. And the clear zone size of water extract (11～27 mm) was greater than that of gentamycin, hexane extract and ethyl acetate extract against S. gallinarium. S. flexneri, K. pneumonia and C. albicans. Minimum inhibitory concentrations(MIC) of water extract appeared to around 2.0～7.5 ㎎/㎖ against S. gallinarium, S. flexneri, E. cloacae and K. pneumonia. The greater activity was shown by water extract because the MIC of water extract for C. albicans observed in very low concentration(<1.0 ㎎/㎖) compared to hexane(5.0 ㎎/㎖) and ethyl acetate(10.0 ㎎/㎖). Therefore, these results exhibited that water extract of Allii sativi Bulbus have stronger antimicrobial activity than hexane and ethyl acetate extract, and may be useful as topical medicine of superficial infections causing C. albicans as well as antifungal agents.

• IMMUNE NETWORK
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• 제14권2호
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• pp.100-106
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• 2014

Infection with invasive Shigella species results in intestinal inflammation in humans but no symptoms in adult mice. To investigate why adult mice are resistant to invasive shigellae, 6~8-week-old mice were infected orally with S. flexneri 5a. Shigellae successfully colonized the small and large intestines. Mild cell death was seen but no inflammation. The infected bacteria were cleared 24 hours later. Microarray analysis of infected intestinal tissue showed that several genes that are involved with the sphingosine-1-phosphate (S1P) signaling pathway, a lipid mediator which mediates immune responses, were altered significantly. Shigella infection of a human intestinal cell line modulated host S1P-related genes to reduce S1P levels. In addition, co-administration of S1P with shigellae could induce inflammatory responses in the gut. Here we propose that Shigella species have evasion mechanisms that dampen host inflammatory responses by lowering host S1P levels in the gut of adult mice.