• 한국수산과학회지
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• 제30권6호
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• pp.1013-1020
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• 1997

The cellular fatty acids of 47 marine bacteria representing the genus Alteromonas, Arthrobacter, Bacillus, Micrococcus, Pseudomonas, Shewanella, Staphylococcus and Stenotrophomonas were determined by a gasliquid chromatographic analysis. Sixty-eight different fatty acids with 10 to 20 carbon atoms were detected in marine bacteria. Of the eight genus examined, 14:0, 16:0 and i17:0 were detected in all, while i14:0, a15:0, i16:0, and 15:0 were found in most of all. There were significant differences in the fatty acid patterns between Gram positive and Gram negative bacteria. Bacteria of Gram positive genus showed relatively high contents of the branched type fatty acids, while the major fatty acids in Gram negative were unsaturated and straight forms. Phylogenetic relationships between marine bacteria defined by the cellular fatty acid patterns represented obvious differences between Gram positive and Gram negative genera, even in respective genus. Therefore, the bacterial classification and identification can be accomplished more easily and rapidly based on the cellular fatty acid profiles than the conventional methods.

• 대한수의학회지
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• 제20권1호
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• pp.53-58
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• 1980

Antimicrobial susceptibility of 157 Gram-negative bacilli (90 Escherichia coli. 30 Enterobacter aerogenes, 18 Klebsiella pneumoniae, 12 Proteus spp., 3 Pseudomonas aeruginosa and 4 Alcaligenes faecalis) isolated from infected bovine udders was determined by the plate dilution method. Gentamicin and oxolinic acid at a concentration of $12.5{\mu}g/ml$ were very active to all of 157 Gram-negative bacilli tested, and 98% of these strains were susceptible to nalidixic acid at a concentration of $25{\mu}g/ml$. Most of the 90 Escherichia coli strains were inhibited by chloramphenicol, ampicillin and carbenicillin and carbenicillin at a concentration of $12.5{\mu}g/ml$. None of the Klebsiella pneumoniae strains were inhibited at a concentration of $50{\mu}g/ml$ of ampicillin and carbenillin, whereas all the species of Proteus resisted a concentration of $50{\mu}g/ml$ or higher tetracycline. All the 3 strains of Pseudomonas aeruginosa were highly resistant to streptomycin, kanamycin, Ampicillin, chloramphenicol, tetracycline and nalidixic acid.

• The Korean Journal of Physiology and Pharmacology
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• 제13권1호
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• pp.39-47
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• 2009

Gaegurin 4(GGN 4), an antimicrobial peptide isolated from a Korean frog, is five times more potent against Gram-positive than Gram-negative bacteria, but has little hemolytic activity. To understand the mechanism of such cell selectivity, we examined GGN4-induced $K^+$ efflux from target cells, and membrane conductances in planar lipid bilayers. The $K^+$ efflux from Gram-positive M. luteus(2.5 ${\mu}g/ml$) was faster and larger than that from Gram-negative E. coli(75 ${\mu}g/ml$), while that from RBC was negligible even at higher concentration(100 ${\mu}g/ml$). GGN4 induced larger conductances in the planar bilayers which were formed with lipids extracted from Gram-positive B. subtilis than in those from E. coli(p<0.01), however, the effects of GGN4 were not selective in the bilayers formed with lipids from E. coli and red blood cells. Addition of an acidic phospholipid, phosphatidylserine to planar bilayers increased the GGN4-induced membrane conductance(p<0.05), but addition of phosphatidylcholine or cholesterol reduced it(p<0.05). Transmission electron microscopy revealed that GGN4 induced pore-like damages in M. luteus and dis-layering damages on the outer wall of E. coli. Taken together, the present results indicate that the selectivity of GGN4 toward Gram-positive over Gram-negative bacteria is due to negative surface charges, and interaction of GGN4 with outer walls. The selectivity toward bacteria over RBC is due to the presence of phosphatidylcholine and cholesterol, and the trans-bilayer lipid asymmetry in RBC. The results suggest that design of selective antimicrobial peptides should be based on the composition and topology of membrane lipids in the target cells.

• 생약학회지
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• 제18권1호
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• pp.1-4
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• 1987

The methanol and benzene extracts of the leaves of 55 higher plants in Korea were tested for their antibacterial activity against three Gram positive bacteria, Streptococcus mutans, Staphylococcus aureus and Bacillus subtilis, and one Gram negative bacterium Escherichia coli. Among them, the methanol extract of the leaves of Liriodendron tulipifera showed remarkably potent antibacterial activity against both Gram positive and negative bacteria.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.26-33
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• 2002

The seven strains, Pseudomonas paucimobilis, Pseudomonas cepacia, Staphylococcus auricularis, Staphylococcus saprophyticus, Acidovorax spp., Acinetobacter calcoaceticus, and Actinobacillus capsulatus were tested with three slimicides. Most of the tested bacteria were inhibited with slimicide K (an isothiazolin based compound), even at its low concentration, except for Actinobacillus capsulatus and Staphylococcus auricularis. Both slimicides B (an organic bromine based compound) and S (aldehydes) also couldn't prevent these two strains even at their highest concentration. Five different sizes of plasmid DNA were isolated from Actinobacillus capsulatus. Staphylococcus auricularis, a gram-positive bacteria, showed the slimy substances around its cell distinctively. The results suggest that two strains, Actinobacillus capsulatus, Staphylococcus auricularis, have presumably developed a resistance to the slimicide, by plasmid DNA or slimy substance. Our findings also suggest that not only gram-negative bacteria, but also gram-positive bacteria should not be neglected

• 한국동물위생학회지
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• 제20권2호
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• pp.151-159
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• 1997

This study was carried out to isolate of causative agents from CMT-positive and mean somatic cell count(SCC) $\geq$500,000 cells/ml mastitic milk, and evaluate to antimicrobial susceptibility of isolates in Iksan branch area from January to November, 1996. 1. The CMT-positivity(SCC 500,000 cells/ml) of 610 heads was 36.2% (221), and of 2,373 quarter milks was 16.1% (383). 2. The Gram-positive isolates were 153 strains which was Staphylococcus sp (115), Micrococcus sp (18), Streptococcus sp (10), Listeria monocytogenes (5) and Enterococcus faecalis(5). 3. The Gram-negative isolates were 66 strains including E coli(14), Yersinia sp (13), Shigella sp(8), Enterobacillus sp(8), Cedecea sp(5), Pseudomonas aeruginosa(5), Proteus sp(5), Klebsiella sp(4), Salmonella sp(2), kluyvera ascorbate(1) and Tatumella ptyseos (1). 4. The Gram positive strains of isolates were moderately susceptible to T/s, Cp, Fd, Imp, Aug, Rif, Cft and Va. And the Gram negative strains of Isolates were moderately susceptible to T/s, Cp, Imp, Pi and Ti, In order. 5. Multiple antimicrobial resistant patterns were encountered 62 and 36 from Gram positive and negative isolates, respectively.

• 대한수의학회지
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• 제40권1호
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• pp.72-80
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• 2000

Lipopolysaccharides (LPS) of Pasteurella multocida (P multocida) and several Gram-negative bacterial pathogens were analyzed by methanolysis, trifluoroacetylation and gas chromatography (GC) on a fused-silica capillary column. The GC analysis indicated that LPS prepared from a strain of P multocida by phenol-water (PW) or trichloroacetic acid (TCA) extraction were quite different in chemical composition. However, LPS prepared from Salmonella enteritidis by the two extraction methods were very similar. PW-LPS extracts from different Pasteurella strains of a serotype had essentially identical GC patterns. Endotoxic LPS extracted from 16 different serotypes of P multocida by PW or by phenol-chloroform-petroleum ether procedures yielded chromatograms indicating similar composition of the fatty acid moieties but minor differences in carbohydrate content. When the chemical composition of endotoxic LPS extracted from several Gram-negative bacteria (P multocida, Pasteurella hacmolytica, Haemophilus somnus, Actinobacillus ligniersii, Brucella abortus, Treponema hyodysenteriae, Escherichia coli, Bacteriodes fragilis, Salmonella abortus equi and Salmonella enteritidis) were examined, each bacteria showed a unique GC pattern. The carbohydrate constituents in LPS of various Gram-negative bacteria were quite variable not only in the O-specific polysaccharides but also in the core polysaccharides. The LPS of closely related bacteria shared more fatty acid constituents with each other than with unrelated bacteria.

• 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.

• 미생물학회지
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• 제34권1_2호
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• pp.31-36
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• 1998

지네 Scolopendra subspinipes multilans L. Koch로부터 정제한 Centipedin의 gram-negative, gram-positive bacteria 및 fungi에 대한 광범위 항균 spectrum을 조사하였으며 액체배지를 사용하여 각 균주에 대한 minimal inhibitory concentrations(MICs)값을 측정하였다. 인체의 기관중 주로 폐에 감염되는 gram-negative bacteria인 Klebsiella pneumoniae ATCC 8308 균주에 대한 MIC값이 $2{\mu}g/ml$로서 가장 강한 항균력을 나타내었고 화농균인 Proteus vulgaris NRRL B-123 균주에 대해서도 MIC값이 $16{\mu}g/ml$로 비교적 높은 항균력을 나타내었으며 항균제로서의 작용 mechanism을 시험한 결과 prokaryotic RNA transcription을 억제함을 알 수 있었다. Human blood leukemia(HL-60)와 mouse B lymphocyte myeloma cell 등의 동물세포에 대한 Centipedin의 cytotoxicity는 없는 것으로 확인되었다.

• 대한한방내과학회지
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• 제26권3호
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• pp.521-532
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• 2005

Objectives & Methods : In order to evaluate the in vitro synergic effects or Eunkyo-san which is a traditional poly-herbal formula that has been used in the treatment of respiratory diseases in oriental medicine, and quinolone antibiotics, rufloxacin (RUFX) and iprofloxacin(CPFX), experimentation was designed to determine minimal inhibitory concentration(MIC), $MIC_{50}\;and\;MIC_{90}$ of single use of quinolones and concomitant treatment with Eunkyo-san against 5 strains of aerobic gram negative bacteria, Escherichia coli, Klebsiella peumoniae, Hemophilus influenzae, Citrobacter freundii and Pseudomonas aeruginosae. Result : In the case of aerobic gram negative bacteria, the MIC, $MIC_{50}\;and\;MIC_{90}$ against Klebsiella peumoniae and Citrobacter freundii significantly decreased in concomitant-treated groups with Eunkyo-san compared to those of single-treated groups of RUFX and CPFX, respectively. However, no significant changes were demonstrated against Echerichia coli, Hemophilus influenzae and Pseudomonas aeruginosae. Conclusion : According to these results, concomitant use of Eunkyo-san against some strains of aerobic gram-negative bacteria dramatically increases in vitro antibacterial activity of RUFX and CPFX, and the increase and selectivity of antibacterial activities against these strains is attributable to Eunkyo-san, and not RUFX or CPFX activity.