• Title/Summary/Keyword: susceptibility test

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Screening of New Bioactive Materials from Microbial Extracts of Soil Microorganism (I) Antimicrobial Activity from 200 Sampled Using Microdilution Assay

  • Jung, Sang-Oun;Kim, Joon;Chang, Il-Moo;Ryu, Jae-Chun
    • Archives of Pharmacal Research
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    • v.21 no.3
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    • pp.278-285
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    • 1998
  • The microdilution assay recommended by NCCLS (National Committee for Clinical Laboratory Standards) is one of the standardized methods of antibiotic susceptibility test. This method has been widely used clinically to obtain MIC values of antibiotics on pathogenic microorganisms. It is more convenient, rapid and simple to test many samples than other test methods such as agar diffusion assay and broth macrodilution assay. The screening of antimicrobial agents from microbial extracts is too laborious in its process. Therefore, a number of screening methods having more simple procedure have been developed. In our laboratory, we applied microdilution assay for screening the antimicrobial agents. This assay showed dose-response results and was more sensitive than disc diffusion assay in our system. We tested 200 samples of microbial extracts originated from 100 microbial strains and selected several samples as potential candidates. In this report, we show that the microdilution assay is more convenient method in screeing of antibiotic susceptibility than those previously reported.

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Study on the Hydrogen Delayed Fracture Property of TRIP Steel by Slow Strain Rate Testing Method (일정 변형률 시험에 의한 TRIP강의 수소 지연파괴 특성연구)

  • Cho, J.H.;Lee, J.K.
    • Corrosion Science and Technology
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    • v.10 no.4
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    • pp.131-135
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    • 2011
  • The demands of high-strength steel have been steadily increased to reduce the weight of vehicles. Although the TRIP steel has been the promising candidate material for the purpose, high strength hinders the application due to the susceptibility to hydrogen delayed fracture in the corrosive environment. Moreover, the testing method was not specified in the ISO standards. In this work, the test method to evaluate the susceptibility of hydrogen delayed fracture was studied by slow strain rate testing technique. The four test experimental parameters were studied : strain rate, hydrogen charging time, holding time after hydrogen charging, and holding time after cadmium plating. The steel was fractured by hydrogen in case the strain rate was in the range of $1{\times}10^{-4}{\sim}5{\times}10^{-7}/sec$. It was confirmed that the slow strain rate test is effective method to evaluate the susceptibility to hydrogen delayed fracture. The holding time over 24 hrs after hydrogen charging, nullified the hydrogen effect, that is, the specimen was no more susceptible to hydrogen after 24 hrs even though the specimen was fully hydrogen-charged. Moreover, cadmium electroplating could not prevent from diffusing out the hydrogen from the steel in the experiment. The effective experimental procedures were discussed.

Antimicrobial Susceptibility of Microorganisms Isolated from Quarter Milk Samples of Holstein Cows (Holstein 유우의 유즙에서 분리한 유방염 원인균의 항균제 감수성)

  • 이정치;이채용;김상기;이정길;서국현
    • Journal of Veterinary Clinics
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    • v.20 no.2
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    • pp.166-171
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    • 2003
  • Milk samples were collected from a total of 418 quarters of 214 Holstein cows. Of these, samples which were positive on California Mastitis Test (CMT) and above 200,000 cells/ml by somatic cell counts were subjected to bacteriological examination and antimicrobial susceptibility test. Major pathogens responsible for mastitis included coagulase-negative staphylococci (34.3%), coagulase-positive staphylococci (21.5%), gran-negative rod (coliforms and noncoliforms: 12.6%) and Streptococcus spp. (8.4%). These strains were tested with 13 antimicrobial agents by the Kirby and Bauer standardized disc diffusion method. The isolated pathogens were mostly susceptible to amoxicillin and cephalothin, but were resistant to erythromycin.

Studies on the Clostridium perfringens isolated from piglets with diarrhea in Western area of Chonnam province (전남 서부지역 설사 자돈에서 분리한 Clostridium perfringens에 관한 연구)

  • 김내영;오은희;홍갑표;강규칠;정인호;박석준
    • Korean Journal of Veterinary Service
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    • v.21 no.2
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    • pp.141-148
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    • 1998
  • Eighteen strains of Clostpidium perfringens were isolated from the piglets with hemorrhagic enteritis. The characteristics of the outbreaks, clinical signs and lesions were examined. The biochemical properties, type of toxins and susceptibility to antimicrobial agents against the isolates were investigated. 1. The incidence of diarrhea was appeared in 97(22.4%) of 432 piglets examined. 2. The isolation rate of Cl perfingens from the 97 diarrheal faeces were 18.5%(18 strains) 3. The population of Cl perfingens in feces were ranged $10^{8-9}$cfu/g in 5(32.5%) and $10^{3-7}$cfu/g in 13(67.4%) of 18 samples. 4. The toxin type of the 18 isolates investigated by mouse inoculation test was all type C strains of Cl perfringens. 5. As a results of antimicrobial susceptibility test, 18 isolates were higly susceptible to cephalothin, tetracycline and penicillin.

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Interpretation of Antimicrobial Susceptibility Test According to Resistance Mechanism of ${\beta}$-lactam in Enterobacteriacae (장내세균에서 ${\beta}$-lactam 항균제의 내성기전별 항균제 감수성검사의 해석)

  • Lee, Chae-Hoon
    • Journal of Yeungnam Medical Science
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    • v.27 no.1
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    • pp.8-17
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    • 2010
  • It is important to select appropriate antimicrobials for the treatment of infection according to the results of antimicrobial susceptibility tests (ASTs), yet the clinical isolates are sometimes susceptible to antibiotics that are clinically ineffective or this is due to technical error of the ASTs. So, interpretive reading of ASTs is needed and especially for the ${\beta}$-lactams for treating $Enterobacteriacae$. This review describes the interpretive reading of ASTs according to natural antimicrobial resistance and the mechanisms of mechanisms, with giving special attention to the antibiotics phenotypes for $Enterobacteriacae$. Further, as all the diffent tissues have a different antimicrobial concentration for identical antimicrobials, more information is needed on the antimicrobial tissue distribution for the appropriate treatment of infection. (ED note: I hope you send me the paper.)

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Study on the hydrogen embrittlement crack susceptibility of stainless steel overlaid weld metal (1) (스테인레스강 Overlay용접부의 수소취화 균열감수성에 관한 연구 1)

  • 이영호
    • Journal of Welding and Joining
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    • v.8 no.3
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    • pp.39-52
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    • 1990
  • The research is to insure the soundness of the stainless steel overlaid weld metal(21/4Cr-IMo steel + SUS 309L) for a pressure vessel application. Detail studies were conducted for the PWHT influence on the micrstructure and intergranular corrosion characteristics of the overlaid weld metal as well as initiation of hydrogen embrittlement crack(or Disbonding) when welded metal are exposed to the hydrogen atmosphere. Hydrogen was experimentally charged to the overlaid weld metal in order to study PWHT effect on the susceptibility of hydrogen embrittlement crack. The results of this research are as follows: 1. At the bond region, austenite grain of the stainless steel side became coarsed and Cr23C6 type carbide was precipitated at the coarsed austenitic grain boundaries. Intergranular Corrosion width(by Straiss test) increased with increasing PWHT temperature and PWHT time.

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Successful treatment of a severe open wound in a raccoon dog (Nyctereutes procyonoides): antibiotic susceptibility testing supported

  • Myeongsu Kim;Haerin Rhim;Seulgi Gim;Chang-Eun Lee;Hakyoung Yoon;Jae-Ik Han
    • Korean Journal of Veterinary Research
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    • v.63 no.3
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    • pp.29.1-29.5
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    • 2023
  • An adult raccoon dog with extensive, deep, and contaminated wounds on the right hip and multiple fractures was rescued. The open wound was managed daily by debridement and flushing for 3 weeks. Modified active drainage was then performed, and antibiotics administered according to the antibiotic susceptibility test. After 2 weeks, the exudate disappeared and the drain was removed. After monitoring for 1 month, the animal was released in to the wild. This case shows that even if infection remains, rapid wound repair is possible if appropriate antibiotic selection through regular examination and active drainage are combined.

Evaluation on the Reliability of Frost Susceptibility Criteria (동상민감성 판정 기준 신뢰성에 관한 연구)

  • Jin, Hyunwoo;Ryu, Byunghyun;Lee, Jangguen
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.12
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    • pp.37-45
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    • 2017
  • Structural instability and damage are caused by frost heave during the winter when atmospheric temperature maintains below $0^{\circ}C$. Frost heave is the most representative engineering characteristics of frozen ground and there are various frost susceptibility criteria. Frost susceptibility criteria can be roughly divided into three categories. First, frost susceptibility is determined from particle size distribution, which is practically useful and many countries are adopting. In this paper, several particle size distributions (PSDs) are applied to the frost susceptibility criteria but PSD seems to be not enough to determine whether soils are frost susceptible. Second, it is judged from laboratory frost heave testing results. Laboratory frost heave tests were performed with newly developed thermal controlled triaxial cell and the reliability of frost susceptibility criteria is evaluated. New testing apparatus and method are suitable to meet the existing frost susceptibility criteria. Third, it is compositive frost susceptibility criteria envelope including the particle size distribution, soil classification, and frost heave test. The compositive frost susceptibility criteria envelope should be supplemented based on additional data on various soil types.

Bovine dermatophytosis and susceptibility of the isolates to antifungal drugs (소 피부사상균증의 발생상황 및 분리균의 약제감수성)

  • 오강희;박노찬;도재철;임소정;박진희
    • Korean Journal of Veterinary Service
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    • v.26 no.1
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    • pp.57-65
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    • 2003
  • The present study was conducted to examine the outbreak state of bovine dermatophytosis in 14 farms(4 dairy farms, 10 Korean indigenous cattle farms) in Gyeongbuk province from November 2000 to November 2001. The causative agents of dermatophytosis was identified by mycological examination. Antifungal susceptibility test of 26 isolates was performed by agar dilution method, using 5 antifungal drugs. Prevalence of bovine dermatophytosis was found to be 13.5%(90/665) in dairy cattle farms and 14.5%(220/1,520) in Korean indigenous cattle farms. The most common age at which this disease occurred was 2-12 months. This disease usually occurred from winter to spring and the occurrence subsequently decreased in the summer. But 4 Korean indigenous cattle farms with poorly hygienic status were occurred all the year round. The causative agent was identified as Trichophyton verrucosum exclusively in these case. Antifungal susceptibility test of T verrucosum (26 strains) was performed by agar dilution method, using 5 antifungal drugs including tolnaftate, griseofulvin, ketoconazole, amphotericin B and terbinafine. All isolates were highly sensitive to 5 antifungal drugs (geometric mean MICs 0.004∼0.032 $\mu\textrm{g}$/$m\ell$). The isolates were the most sensitive to especially tolnaftate.

Solidification Cracking Behavior in Austenitic Stainless Steel Laser Welds (Part 1) - Evaluation of Solidification Cracking Susceptibility by Laser Beam Welding Varestraint Test - (오스테나이트계 스테인리스강 레이저 용접부의 응고균열 거동 (Part 1) - 레이저 용접용 Varestraint 시험 시스템을 이용한 응고균열 민감도 평가 -)

  • Chun, Eun-Joon;Lee, Su-Jin;Suh, Jeong;Kang, Namhyun;Saida, Kazuyoshi
    • Journal of Welding and Joining
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    • v.34 no.5
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    • pp.54-60
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    • 2016
  • In order to quantitatively evaluate the solidification cracking susceptibility in laser welds of three types of austenitic stainless steels (type 310: A mode, type 316-A: AF mode, type 316-B: FA mode solidifications), the laser beam welding (LBW) transverse-Varestraint tests consisted of multi-mode fiber laser, welding robot and hydraulic pressure system were performed. As the welding speed increased from 1.67 to 40.0 mm/s, the solidification brittle temperature range (BTR) of laser welds for type 316 stainless steels enlarged (316-A: from 37 to 46 K, 316-B: from 14 to 40 K), while the BTR for type 310 stainless steel reduced from 146 to 120 K. In other words, it founds that solidification cracking susceptibility could not be simply mitigated through application of LBW process, and the BTR variation behavior is quite different upon solidification mode of austenitic stainless steels.