• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1481-1489
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• 2021

Early and accurate detection of pathogens is important to improve clinical outcomes of bloodstream infections (BSI), especially in the case of drug-resistant pathogens. In this study, we aimed to develop a culture-independent digital PCR (dPCR) system for multiplex detection of major sepsis-causing gram-negative pathogens and antimicrobial resistance genes using plasma DNA from BSI patients. Our duplex dPCR system successfully detected nine targets (five bacteria-specific targets and four antimicrobial resistance genes) through five reactions within 3 hours. The minimum detection limit was 50 ag of bacterial DNA, suggesting that 1 CFU/ml of bacteria in the blood can be detected. To validate the clinical applicability, cell-free DNA samples from febrile patients were tested with our system and confirmed high consistency with conventional blood culture. This system can support early identification of some drug-resistant gram-negative pathogens, which can help improving treatment outcomes of BSI.

• 생명과학회지
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• 제25권12호
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• pp.1458-1469
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• 2015

유기용매 내성 세균의 첫 분리 보고 이후 다수의 유기용매 내성 세균들이 토양 폐수 심지어 심해 등 모든 환경에서 분리 보고되고 있다. 대부분의 유기용매 내성 세균은 그람음성세균으로 이는 그람음성 세균이 그람양성 세균 보다 유전적으로 더 내성을 보이기 때문이다. 유기용매 내성 기전은 유기용매 내성 그람음성 세균을 주로 사용하여 집중적으로 구명되어왔다. 유기용매 내성 그람양성 세균의 유기용매 내성 기전은 비교적 최근 연구에서 발견되고 있다. 유기용매는 용매에 따라 다른 독성을 보이며 유기용매 내성세균의 유기용매 내성 수준은 종과 균주에 의존적으로 매우 변화가 심하다. 그러므로 유기용매 내성세균은 다양한 변인과 다유전자에 의한 적응 전략에 의하여 용매독성과 싸우며 용매 스트레스에 적응할 수 있다. 그들은 세포형태 및 세포 행동에서의 변화, 세포표층의 수식, 세포막 적응, 용매 배출 펌프, 샤페론 그리고 항산화 반응 등의 기전을 통하여 유기용매의 과량의 농도에서도 생존할 수 있다. 본 총설에서는 대표적인 유기용매 내성 세균, 유기용매 내성 세균에서의 유기용매에의 적응 및 내성 전략들 나아가 그들의 산업적 및 환경공학적인 잠재적인 영향에 대하여 개관하고자 한다.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.671-678
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• 2018

Papiliocin, isolated from the swallowtail butterfly (Papilio xuthus), is an antimicrobial peptide with high selectivity against gram-negative bacteria. We previously showed that the N-terminal helix of papiliocin (PapN) plays a key role in the antibacterial and anti-inflammatory activity of papiliocin. In this study, we measured the selectivity of PapN against multidrug-resistant gram-negative bacteria, as well as its anti-inflammatory activity. Interactions between Trp2 of PapN and lipopolysaccharide (LPS), which is a major component of the outer membrane of gram-negative bacteria, were studied using the Trp fluorescence blue shift and quenching in LPS micelles. Furthermore, using circular dichroism, we investigated the interactions between PapN and LPS, showing that LPS plays critical roles in peptide folding. Our results demonstrated that Trp2 in PapN was buried deep in the negatively charged LPS, and Trp2 induced the ${\alpha}$-helical structure of PapN. Importantly, docking studies determined that predominant electrostatic interactions of positively charged arginine residues in PapN with phosphate head groups of LPS were key factors for binding. Similarly, hydrophobic interactions by aromatic residues of PapN with fatty acid chains in LPS were also significant for binding. These results may facilitate the development of peptide antibiotics with anti-inflammatory activity.

• 한국수산과학회지
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• 제54권4호
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• pp.377-387
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• 2021

Fecal contamination levels of discharge water from inland pollution sources were investigated in Iwon-myeon (Taean-gun), South Korea. Gram-negative bacteria were isolated during the investigation and the antimicrobial resistance patterns of the isolates were examined to estimate their impact on the coastal environment. The ranges of total coliform and fecal coliform of 12 samples from four major inland pollution sources were 79-490,000 MPN/100 mL and 2.0-490,000 MPN/100 mL, respectively, with the highest level of fecal contamination at Station No. 3. A total of 137 strains (14 genus) were isolated, of which 86 strains (62.8%) were Enterobacteriaceae. The identified isolates were as follows: Pseudomonas spp. (35 strains), Klebsiella spp. (20 strains), Serratia spp. (20 strains), and Escherichia spp. (19 strains). The isolated Gram-negative bacteria showed the highest antimicrobial resistance to ampicillin (81.8%), followed by amoxicillin/clavulanic acid (64.2%), ceftiofur (61.3%), and cefoxitin (59.1%). Antimicrobials in which less than 10% of isolates showed antimicrobial resistance were ciprofloxacin (3.6%) and gentamicin (2.2%). Resistance to one or more antimicrobials was observed in 121 strains (88.3%) and 84 strains (61.3%) showed a tendency for multiple antimicrobial resistance.

• KSBB Journal
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• 제26권6호
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• pp.543-551
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• 2011

Bacterial antibiotic resistance is a real and growing problem for both Gram positive and Gram negative bacterial pathogens in the hospital setting. Among Gram negative bacteria, the ubiquitous bacterium Pseudomonas aeruginosa is a particular concern in immunocompromised and burn patients. The present study evaluated antibacterial activity and efficacy of a Korean herbal medicine against eight multi-drug resistant clinical isolates of P. aeruginosa (0225, 0254, 0347, 0826, 1113, 1378, 1731, and 2492) isolated at Daegu Catholic University Hospital. Methanol extracts of Galla rhois (5 and 10 mg/mL) displayed inhibition diameters for isolate 2492 of 10 and 12 mm, respectively, in a conventional disc diffusion assay. In seven kinds of Korean herbal medicines, increased inhibitory power of Lonicera japonica, Gardenia jasminoides, Galla rhois, and Scultellaria baicalensis was evident with the fermentation of six kinds of lactic acid bacteria. Three lactic acid bacteria (Lactobacillus plantarum subsp. plantarum KCTC 3108, L. casei KCTC 3109, and L. fermentum KCTC 3112) were identified as excellent strains for the production of antibacterial materials. In the six Korean herbal medicine extracts, strong inhibitory activity of fermented Forsythia suspensa, Glycyrrhizae radix, Lycium chinense, Platycodon grum, and Schizandra chinensis with five kinds of lactic acid bacteria was evident for seven multi-drug resistant P. aeruginosa isolates.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.307-308
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• 2005

Bioconverted hydroxy fatty acid from ${\gamma}-linolenic$ acid showed antibacterial activity against Gram-positive bacteria such as Bacillus subtilis (ATCC 6633), Listeria monocytogenes (ATCC 19166), Staphylococcus aureus (ATCC 6538) and S. aureus (KCTC 1916) and one Gram-negative bacteria, Pseudomonas aeruginosa (KCTC 2004) with MIC ranging from 250 to $750\;{\mu}g/ml$ against five of eleven bacteria tested.

• 한국자기공명학회논문지
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• 제19권2호
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• pp.54-60
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• 2015

Papiliocin, from the swallowtail butterfly, Papilio xuthus, shows high bacterial cell selectivity against Gram-negative bacteria. Recently, we designed a 22mer analog with N-terminal helix from $Lys^3$ to $Ala^{22}$, PapN. It shows outstanding antimicrobial activity against Gram-negative bacteria with low toxicity against mammalian cells. In this study, we determined the 3-D structure of PapN in 300 mM DPC micelle using NMR spectroscopy and investigated the interactions between PapN and DPC micelles. The results showed that PapN has an amphipathic ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$. STD-NMR and DOSY experiment showed that this helix is important in binding to the bacterial cell membrane. Furthermore, we tested antibacterial activities of PapN in the presence of salt for therapeutic application. PapN was calcium- and magnesium-resistant in a physiological condition, especially against Gram-negative bacteria, implying that it can be a potent candidate as peptide antibiotics.

• Advances in Traditional Medicine
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• 제7권3호
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• pp.286-289
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• 2007

Heracleum nepalense D Don. (Umbelliferae) is a small shrub having high glabrescent stem found in stream banks in Sikkim. Various medicinal properties which include antidiarrhoeal, antiseptic, anti-influenzal etc. have been attributed for this plant in the traditional system of medicine in Sikkim. In present investigation the methanol extract of roots of Heracleum nepalense was subjected for its effectiveness against both Gram-positive and Gram-negative bacteria causing diarrhoea. The roots extract was tested for its minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative organisms causing diarrhoea. Further, the zones of inhibition produced by the crude extract against few sensitive strains was measured and compared with those of standard antibiotic ciprofloxacin. It is evident that the methanol extract is very active against the bacteria causing diarrhoea at low concentrations. The antibacterial efficacy of the root extract was found to decrease in the following order against different tested bacterial strains like Shigella dysenteriae, Escherichia coli, Shigella boydii, Vibrio cholerae, Salmonella typhimurium.

• Natural Product Sciences
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• 제13권4호
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• pp.279-282
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• 2007

The aim of the present study was to investigate the various chemical components present in the cone volatile oil of Cupressus macrocarpa and also determine its antimicrobial activity. Totally 13 compounds were identified with 99.99% by GC-MS analysis. The major compounds identified were terpinene-4-ol (19.42%), dinopol (15.63%), ${\alpha}$-pinene (13.58%), and ${\beta}$-pinene (12.16%). The antimicrobial activity was carried out for the oil and a 2% cream formulation using cup plate method by measuring the zone of inhibition. The gram positive organisms used were Bacillus subtilis, Staphylococcus aureus, Bacillus megaterium, and Bacillus cogulans. The gram negative organisms used were Escherichia coli, Kleibseilla pneumonia, Pseudomonas aeruginosa and Salmonella typhi. In vitro antifungal studies were also carried out by using organisms, Candida albicans, Aspergillus flavus, Trichoderma lignorum and Cryptococcus neoformans. The standard drugs used were penicillin ($100{\mu}g/mL$), gentamycin ($100{\mu}g/mL$) and griseofulvin ($100{\mu}g/mL$) for gram positive bacteria, gram negative bacteria and fungi respectively. Both oil and cream formulation showed good activity against fungi than bacteria. This study is being reported for the first time on cone volatile oil of this plant.

• 한국양식학회지
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• 제14권4호
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• pp.221-226
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• 2001

상백피로부터 항균성 물질을 추출하여 어규질병에 대한 천연 항균약제로서의 이용 가능성을 타진하기 위하여 어류질병세균에 대한 항균활성 및 상백피 추출물에 침지 시킨 사료의 항균작용 등을 검토하였다. 고체배지에서 상백피 에탄올 추출물은 Steptococcus sp., Lactococcus garvieae 및 Staphylococcus sp. 등의 그람양성 세균에 대하여는 강한 항균활성을 나타내었으나, 그람음 성세균인 Listonella anguillarum 및 Edwardsiella tarda에 대하여는 약한 항균활성을 보였다. 액체배지에서 상백피 에탄올 추출물의 그람양성세균에 대한 최소발육저지농도는 19.8 $\mu\textrm{g}$/$m\ell$이었으며, 37.5~118.5 $\mu\textrm{g}$/$m\ell$의 농도에서는 살균작용물 보여 그람양성세균에 대하여는 균 증식을 억제함은 물론 살균작용도 가지고 있음을 알 수 있었다 반면, 그람음성세균에 대한 최저발육저지농도는 790.0~1185.0$\mu\textrm{g}$/$m\ell$이었고, E. tarda에 대하여는 1185.0 $\mu\textrm{g}$/$m\ell$이었고, E. tarda에 대하여는 1185.0 $\mu\textrm{g}$/$m\ell$를 첨가하여도 균을 사멸시키지 못하였다. 사료를 상백피 에탄올 추출물에 침지시 적정 침지 시간은 3분이었고, 상백피 추출물에 침지시킨 사료는 그람양성세균의 증식을 억제하여 10.5~12.0 mm의 저해환을 나타내지 못하였다. 또한, 사료 중량에 따른 추출물 흡수량은 식 Y = 7.5757X + 4.6962 ($R^2$ = 0.9998)으로 아주 밀접한 상관관계를 나타내었다.