• Title/Summary/Keyword: MICs

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Development of New Quinolone Antibacterials with Dextran-bond (Dextran에 결합된 새로운 Quinolone계 항균제의 개발)

  • Kim, Sun-Il;Na, Jae-Woon
    • Applied Chemistry for Engineering
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    • v.5 no.3
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    • pp.501-508
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    • 1994
  • 1-Ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(1-piperazinyl)quinolinea-3-car-boxylic acid-dextran was synthesized by the reaction of 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(1-piperazinyl )quinoline-3-acryloyl chloride with dextran. Polymeric drug was tested for antimicrobial activity in vitro against ten species of microorganisms. Polymeric drug revealed good antibacterial activity against Bacillus subtillis ATCC 6633, Staphyloccus aureus ATCC 25923, Mycrobactertum phlei IFO 3158, Salmonella typhimurium KCTC 1925, Escherichia coli KCTC 1039, Escherichia coli ESS, Klebsiella puemouiae KCTC 1560 and Pseudomonas aeruginosa IFO 13130. Polymeric drug have no antimicrobial against Candida albicans ATCC 10231, but moderately active Micrococcus luteus ATCC 9341.

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Isolation and Evaluation of Protective Effect against Fusarium Wilt of Sesame Plants of Antibiotic Substance from Bacillus polymyxa KB-8

  • Hyun, Jae-Wook;Kim, Young-Hoon;Lee, Yong-Se;Park, Won-Mok
    • The Plant Pathology Journal
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    • v.15 no.3
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    • pp.152-157
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    • 1999
  • An antibiotic compound was isolated from the culture of an antagonist against Fusarium oxysporum f. sp. sesami, Bacillus polymyxa strain KB-8, and tested for the control of Fusarium wilt of sesame in greenhouse conditions. Optimum conditions for culturing the antagonist to obtain the maximum antibiotic activity were determined using different culture media, initial medium acidity, and incubation periods for which yeast -malt extract agar with the initial acidity of pH 5 and over 13 days culture were best. Antibiotic substances extracted by methanol had 2 main fractions, KB-8A and KB-8B, in thin layer chromatography (OLC) with Rf values of 0.35 and 0.67 in a solvent system of chloroform : methanol = 7 : 3. The fraction KB-8A wa purified further by XAD-2, silica gel and Sephadex LH-20 column chromatography, and crystalization. Its minimum inhibitory concentrations (MICs) were $12.8\mu\textrm{g}$/ml for F. oxysporum and Alternaria mali, $6.4\mu\textrm{g}$/ml for Colletotrichum gloeosporioides and Rhizoctonia solani, and $3.2\mu\textrm{g}$/ml for Phytophthora capsici. Soil drenching of antibiotic KB-8A in the concentrations of $13.0\mu\textrm{g}$/ml and $26.0\mu\textrm{g}$/ml effectively inhibited the Fusarium wilt of sesame in a greenhouse test, which appeared to be comparable to the fungicide benlate of $6.5\mu\textrm{g}$ a. i./ml.

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Inactivation of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes by Hydrogen Peroxide and Lactic acid (과산화수소와 유산ol Escherichia coli O157:H7, Salmonella Enteritidis 및 Listeria monocytogenes의 증식 억제에 미치는 영향)

  • Jang Jae-Seon;Lee Mi-Yeon;Lee Jea-Mann;Kim Yong-Hee
    • Journal of environmental and Sanitary engineering
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    • v.19 no.4 s.54
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    • pp.69-75
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    • 2004
  • The inhibitory effect of the food processing agent on growth of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes was performed with hydrogen peroxide and lactic acid, and combination of hydrogen peroxide and lactic acid. The minimun inhibitory concentration (MIC) of hydrogen peroxide in E coli O157:H7 was 100 ppm at pH 5.0, 6.0, 6.5 and 7.0, while in Listeria monocytogenes 25 ppm at PH 5.5, 6.0 and 50 ppm at PH 6.5, 75ppm at pH 7.0. MIC of lactic acid in E coli O157:H7 was 2500 ppm at pH 5.0, 6.0, 6.5 and 7.0. MIC of lactic acid in S. Enteritidis was 1250 ppm at pH 5.0, 2500 ppm at pH 5.5, 6.0, 5.5 and 7.0, while in L monocytogenes 625 ppm at pH 5.5 and 125 ppm at pH 6.0, 6.5 and 7.0. MIC of combined hydrogen Peroxide and lactic acid in E. coli O157:H7, S. Enteritidis, and L. monocytogenes was 75 ppm of hydrogen peroxide with 2500 ppm of lactic acid at pH 6.5. The correlations between MICs of hydrogen peroxide and lactic acid in E. coli O157:H7, S. Enteritidis and L. monocytogene were obtained through the coefficient of $determination(R^2)$. $R^2$ value were 0.9994, 0.9935 and 0.9283, respectively. The inhibitory effect of hydrogen peroxide and lactic acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes could be confirmed from the result of this experiment. Therefore, it was expected that the food process would increase or maintain by using lactic acid together with hydrogen peroxide.

Errors of Antibiotic Susceptibility Testing from Automated and Manual Systems in Clinical Isolates of Acinetobacter baumannii

  • Sung, Ji Youn;Oh, Ji-Eun;Kim, Eun Sun
    • Korean Journal of Clinical Laboratory Science
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    • v.45 no.1
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    • pp.21-25
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    • 2013
  • Acinetobacter baumannii is an aerobic, gram-negative and glucose-non-fermenting bacterium, which has emerged as a serious opportunistic pathogen. Many clinical microbiology laboratories use the Vitek 2 system for the routine antimicrobial susceptibility testing process, including testing on A. baumannii isolates. However, in case of amikacin, it is now recommended to perform additional antimicrobial susceptibility testing for A. baumannii strains due to the relatively lower minimum inhibitory concentration (MIC) in the Vitek 2 system compared to conventional reference methods. In our study, we assessed MIC for amikacin susceptibility testing of A. baumannii isolates in the Vitek 2 system, the agar dilution, Etest, and disk diffusion method. We collected 40 gentamicin-resistant, A. baumannii strains (amikacin MIC by Vitek 2:${\leq}2{\mu}g/mL$, 2 isolates; $4{\mu}g/mL$, 34 isolates; $8{\mu}g/mL$, 4 isolates) from a University hospital and compared the Vitek 2 system to other reference methods for testing susceptibility to amikacin. The Vitek 2 system showed major errors in all of the 40 isolates, yielding a low MIC. The results of our study strongly suggested that the Vitek 2 system was not a reliable method to test the MICs of gentamicin; ranging from ${\geq}16{\mu}g/mL$ for amikacin susceptibility. Other tests, such as agar dilution, Etest, or disk diffusion methods, should be paralleled to determine the MIC of amikacin in A. baumannii.

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Antimicrobial Resistance and Minimum Inhibitory Concentrations of Vibrio parahaemolyticus Strains Isolated from Gomso Bay, Korea (곰소만 해역 해수에서 분리한 장염비브리오(Vibrio parahaemolyticus)의 항균제 내성 및 최소발육억제농도의 구명)

  • Kim, Tae-Ok;Um, In-Seon;Kim, Hee-Dai;Park, Kwon-Sam
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.5
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    • pp.582-588
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    • 2016
  • Seventy-nine Vibrio parahaemolyticus isolates from surface seawater from Gomso Bay, west coast of Korea, were analyzed for the presence of virulence genes and their susceptibility to 30 different antimicrobials. All 79 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction (PCR); however, no isolates possessed either the tdh or trh gene. According to a disk diffusion susceptibility test, all of the strains studied were resistant to oxacillin, penicillin, and vancomycin, followed by ticarcillin (97.5%), ampicillin (96.2%), clindamycin (86.1%), erythromycin (10.1%), streptomycin (7.6%), cefoxitin (6.3%), amikacin (2.5%), and cephalothin (2.5%). However, all of the strains were susceptible to 19 other antimicrobials including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 79 isolates (100%) were resistant to four or more classes of antimicrobials, and two strains exhibited resistance to eight antimicrobial agents. The average minimum inhibitory concentrations (MICs) for V. parahaemolyticus for ampicillin, penicillin, ticarcillin, and vacomycin were 946.5, 1,305.9, 1,032.3, and 45.0 µg/mL, respectively.

A Study on the Mods Look (모즈룩(Mods Look)에 관한 연구)

  • 정연자
    • Journal of the Korean Society of Costume
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    • v.33
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    • pp.189-199
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    • 1997
  • The following contents are the results from the examination of unisex fetishism minimal and active which are Mods look. Unisex-becasue of the changing in musician and the role of sex Mods girl adopted much from men's clothing. The unisex mods look expressed in the 1990s is not the expression confronting the estab-lished value and the confusion of sex as it did in the '60s but possibly the appearance of a fashion trend. Fetishism-in the '60s the Mods look changed mens clothing into more wonman-like clothing which expressed their internal and external values of thinking. this fetishism phenomenon is also strongly expressed among the in the 1990s. This gives a future-orientid feeling by expressing with a modern sense the 60's fetish dress which used woman-like silhouettes bright and stretch fabric colorful and vivid tone. Minimal-The 60's Mods put on mini skirts called the revolution of length as a mode of re-sistance and mininmal dress as a way of ex-pressing the liberation of body and the con-sciousness of beauty. Minimal is reflected well on slim and fit jackets and pants and short and fit pants etc. mods look in the '90s also consists of the general trend of slim and fit silhouette. Active-Mods that reject the value of estab-lished generation in the 60s showed a sporty and casual trend on fashion. Mods works around clubs wore polo shirts and cadigan and Mods enjoys scooter often wore anorak parkas This active style of Mods approched to the young' casual with freshness expressing newly in the '90s polo shirts took a seat as an item of street fashion especially in the beginning of 1996. Mods in the 1960s shows well a fashion flow of the age as a street fashion which expresses the mental world reflected in politics econo-mics society and culture within the people of the age. These Mods looks revived in the early 1990's awaken an importance of the culture of the young as the cultural qualities included in Mods of the past life and this fashion trend expected to take a part as a symbol of fashion culture.

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Effect of Chitosan Acetate on Bacteria Occurring on Neungee Mushrooms, Sarcodon aspratus

  • Park, Bom-Soo;Koo, Chang-Duck;Ka, Kang-Hyeon;Lee, Young-Nam
    • Mycobiology
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    • v.36 no.4
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    • pp.249-254
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    • 2008
  • Minimal growth inhibitory concentrations (MICs) of chitosan acetate (M.W. 60 kDa) on heterotrophic bacteria (strains MK1, S, and R) isolated from the soft-rotten tissues of Neungee mushroom (Sarcodon aspratus) were measured. The slimy substance produced by the MK1 strain was responsible for the diseased mushroom’s appearance. The S and R strains were members of the Burkholderia cepacia complex. These strains showed different levels of susceptibility toward chitosan acetate. The MIC of chitosan acetate against the MK1 and S strains was 0.06%. The MIC against the R strain was greater than 0.10%. Survival fractions of the MK1 and S strains at the MIC were $3\;{\times}\;10^{-4}$ and $1.4\;{\times}\;10^{-3}$ after 24 h, and $2\;{\times}\;10^{-4}$ and $7\;{\times}\;10^{-4}$ after 48 h, respectively. Survival fractions of the R strain after 24 and 48 hr at 0.1% chitosan acetate were $1\;{\times}\;10^{-2}$ and $6.9\;{\times}\;10^{-3}$, respectively. Compared to the MK1 and S strains, the low susceptibility of the R stain towards chitosan acetate could be due to the ability of the R strain to utilize chitosan as a carbon source. Thirty-eight percent of Neungee pieces treated in a 0.06% chitosan acetate solution for $2{\sim}3$ second did not show any bacterial growth at 4 days, whereas bacterial growth around untreated mushroom pieces occurred within 2 days. These data suggest that chitosan acetate is highly effective in controlling growth of indigenous microorganisms on Neungee. The scanning electron micrographs of the MK1 strain treated with chitosan revealed a higher degree of disintegrated and distorted cellular structures.

Characterization of Trimethoprim-Sulfamethoxazole Resistance Genes and Their Relatedness to Class 1 Integron and Insertion Sequence Common Region in Gram-Negative Bacilli

  • Shin, Hae Won;Lim, Jinsook;Kim, Semi;Kim, Jimyung;Kwon, Gye Cheol;Koo, Sun Hoe
    • Journal of Microbiology and Biotechnology
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    • v.25 no.1
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    • pp.137-142
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    • 2015
  • Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infections, but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram-negative bacilli. Consecutive nonduplicate TMP-SMX nonsusceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. The minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons, and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMP-SMX. Their MICs were all over 640. In E. coli and K. pneumoniae, sul1 and dfr genes were highly prevalent in relation with integron1. The sul3 gene was detected in E. coli. However, in P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron; however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pneumoniae, and Acinetobacter spp. but the relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in six isolates of E. coli. In conclusion, resistance mechanisms for TMP-SMX were different between Enterobacteriaceae and glucose non-fermenting gram-negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram-negative baciili, so the adoption of prudent use of antimicrobial agents and the establishment of a surveillance system are needed.

Antimicrobial activities of Ramaria botrytis (Fr.) against oral bacteria (싸리버섯 추출물의 구강세균에 대한 항균활성)

  • Kim, Ki-Hwa;Han, So-Ra;Kim, Byeol-Lee;Jung, Sang-Hee;Oh, Tae-Jin
    • Journal of Korean society of Dental Hygiene
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    • v.17 no.3
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    • pp.493-504
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    • 2017
  • Objectives: This study aimed to find out the antimicrobial activities of Ramaria botrytis (Fr.) extracts against oral pathogens. Methods: The antimicrobial activities of Ramaria botrytis (Fr.) extracts were evaluated against oral pathogens by the disc diffusion assay, and the minimum inhibitory concentrations (MICs) of ethyl acetate extracts were determined by broth dilution method. The strains used in this study were Staphylococcus aureus, Streptococcus mutans, Streptococcus sanguinis, Streptococcus sobrinus, Streptococcus anginosus, Streptococcus ratti, Streptococcus criceti, Actinomyces israelii, Actinomyces viscosus and Aggregatibacter actinomycetemcomitans. Results: The ethyl acetate extract of Ramaria botrytis (Fr.) effectively inhibited the growth of oral bacteria compared with acetone or ethanol extract. The ethyl acetate extract exhibited MIC values ranging from 3.75 to 15.00 mg/ml, and it showed antimicrobial activity against both Gram-positive and negative oral bacteria. Conclusions: The ethyl acetate extracts from Ramaria botrytis (Fr.) showed the antimicrobial activities against ten oral bacteria. Thus, the extract of Ramaria botrytis (Fr.) may be considered as an effective natural antimicrobial agent for the prevention of oral pathogens.

Susceptibility Testing of Helicobacter pylori to Metronidazole and DNA Fingerprints of Resistant Strains in Singapore

  • HUA, JIESONG;KHAY-GUAN YEOH;PENGYUAN ZHENG;HAN CHONG NG;BOW HO
    • Journal of Microbiology and Biotechnology
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    • v.9 no.3
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    • pp.328-333
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    • 1999
  • Susceptibility of 61 strains of Helicobacter pylori to metronidazole was examined by both the disk diffusion method using a cut-off of 15㎜ for resistance and the E test with a cut-off of 8㎎/l. The MIC/sub 50/ and MIC/sub 90/ by the E test were 2 ㎎/l and 256㎎/l, respectively. Metronidazole resistance was found in 22 (36%) out of the 61 H. pylori strains by the E test and in three additional strains by the disk diffusion method. Amongst the latter three isolates, the MICs by the E test were 4 ㎎/l, 6㎎/l, and 6㎎/l, respectively. These figures are one log₂ or half log₂ dilution lower than the cut-off of 8㎎/l recommended as resistance for the E test. All 22 metronidazole resistant H. pylori isolates by the E test that were subjected to random amplified polymorphic DNA (RAPD) fingerprinting showed different DNA fingerprints. Interestingly, >90% of resistant isolates possess two common DNA bands of 0.4 and 0.9 kb. This study demonstrates that the results of the disk diffusion method for testing H. pylori susceptibility to metronidazole correlates well with that of the E test. The criteria for interpretation need to be internationally standardized so that the results from different centers can be compared.

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