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Disc Diffusion (disc + diffusion)

Distribution by Scientific Domains
Medical Sciences60%

Terms modified by Disc Diffusion

  • disc diffusion method
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    Selected Abstracts

    In vitro antibiotic susceptibility of bacteria isolated from EUS-affected fishes in India

    LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2002
    D. Saha
    Aims:,Twelve antibiotics were evaluated for in vitro sensitivity against 16 bacterial strains isolated from surface lesions of fishes affected with epizootic ulcerative syndrome (EUS). Methods and Results:,Disc diffusion assay in Mueller-Hinton agar showed that the pseudomonads and aeromonads were mainly resistant to penicillin, ampicillin and erythromycin. Additionally, some were resistant to gentamycin and amoxycillin. However, resistance towards antibiotics previously recommended for EUS treatment, such as oxytetracycline and chloramphenicol, was not observed. Four aeromonads and two pseudomonads were found to induce ulcers when injected intramuscularly in healthy Anabas testudineus. Conclusions:,All six pathogenic isolates were sensitive towards oxytetracycline, chloramphenicol and nalidixic acid. Oxytetracycline seems to be an effective antibiotic, and further investigations to determine the mode of treatment and dose appear to be worthwhile. [source]

    Determination of survival, identity and stress resistance of probiotic bifidobacteria in bio-yoghurts

    LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2006
    V.S. Jayamanne
    Abstract Aims:, To determine the level of bifidobacteria in bio-yoghurts in the UK, identify the species, and compare the resistance of common Bifidobacterium spp. to acidity and oxidative stress. Methods and Results:, A storage trial of bio-yoghurts was carried out to determine the level and survival of bifidobacteria. The 16S rRNA gene targeted PCR was used to identify the species. Acid tolerance was determined by introducing the organisms to pH-adjusted skimmed milk and enumerating during storage at 4°C. Oxidative stress resistance was determined using the H2O2 disc diffusion assay technique. Nine of 10 bio-yoghurts contained bifidobacteria at levels >106 CFU g,1 at the time of purchase. The viability of the organism decreased during storage and on expiry only five products retained viability >106 CFU g,1 while two others were very close to the target population. Bifidobacterium animalis ssp. lactis showed superior survival abilities and stress tolerance compared with Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium bifidum, Bifidobacterium adolescentis and Bifidobacterium longum biotype infantis. Conclusions:,Bifidobacterium animalis ssp. lactis, the only Bifidobacterium spp. found in bio-yoghurts, had the greatest resistance to acidity and oxidative stress. Significance and Impact of the Study:, The technological properties of B. animalis ssp. lactis make it suitable for inclusion in bio-yoghurts although its putative health benefits need further investigation. [source]

    In vitro susceptibility-testing in Aspergillus species

    MYCOSES, Issue 5 2008
    Cornelia Lass-Flörl
    Summary Aspergillus species are the most common causes of invasive mould infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility-testing. Various testing procedures have been proposed, including macrodilution and microdilution, agar diffusion, disc diffusion and Etest. At present, one of the most widely used assays is the M38-A reference method for filamentous fungi, published by the Clinical Laboratory Standard Institute and the Etest. Recently, the European Committee on Antimicrobial Susceptibility-testing (EUCAST) has charged its Antifungal Susceptibility-testing Subcommittee (AFST-EUCAST) with the preparation of new guidelines for in vitro susceptibility-testing of antifungals against Aspergillus spp. (EUCAST-AFST-ASPERGILLUS) defining breakpoints. This paper reviews the available methods for antifungal susceptibility-testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing. [source]

    Screening of herbal extracts against multi-drug resistant Acinetobacter baumannii

    PHYTOTHERAPY RESEARCH, Issue 8 2010
    Yoko Miyasaki
    Abstract Antibiotic resistance is increasing resulting in a decreasing number of fully active antimicrobial agents available to treat infections with multi-drug resistant (MDR) bacteria. Herbal medicines may offer alternative treatment options. A direct inoculation method simulating the standard disc diffusion assay was developed to determine in vitro antimicrobial activity of sixty herbal extracts against MDR- Acinetobacter baumannii (A. baumannii). Eighteen herbal extracts inhibited MDR- A. baumannii on agar plates, although the magnitude and quality of bacterial inhibition differed considerably among the antibacterial herbal extracts. Next, minimal inhibitory concentration (MIC) of these antibacterial herbal extracts was calculated using a broth microdilution assay. For most herbal extracts, the larger the zone of inhibition on agar plates, the lower the MIC. In general, hetero-resistance on agar plates correlated with higher MIC. The skip well phenomenon was seen with two herbal extracts. In conclusion, 30% of the screened herbal extracts demonstrated in vitro antibacterial activity against MDR- A. baumannii using similar rigorous testing methods as those commonly employed for assessing antimicrobial activity of synthetic antibacterial agents. Characterization of a specific compound conferring this antibacterial activity of the herbal extracts may help to identify novel antimicrobial agents active against highly resistant bacteria. Copyright © 2010 John Wiley & Sons, Ltd. [source]

    Vancomycin-resistant Enterococcus spp.: validation of susceptibility testing and in vitro activity of vancomycin, linezolid, tigecycline and daptomycin

    APMIS, Issue 1 2010
    MATHIAS RATHE
    Rathe M, Kristensen L, Ellermann-Eriksen S, Thomsen MK, Schumacher H. Vancomycin-resistant Enterococcus spp.: validation of susceptibility testing and in vitro activity of vancomycin, linezolid, tigecycline and daptomycin. APMIS 2010; 118: 66,73. Vancomycin-resistant enterococci (VRE) have emerged to become a significant nosocomial pathogen. However, detection may be challenging and treatment possibilities are limited. Reports of resistance to linezolide, daptomycin and tigecycline underline the need for reliable susceptibility testing with respect to these compounds. We evaluated the in vitro activity of vancomycin, linezolid, daptomycin and tigecycline against a panel of VRE and vancomycin-susceptible enterococci by broth microdilution (BMD). Etest for determination of minimum inhibitory concentration of these four antibiotics and two disc diffusion assays for detecting VRE and for susceptibility testing against tigecycline and linezolid were evaluated. Before susceptibility testing, all isolates were classified by polymerase chain reaction as vanA or vanB gene positive or vanA/B gene negative. Linezolid, daptomycin and tigecycline had excellent in vitro activity towards all isolates. For daptomycin and tigecycline, the overall agreement between BMD and Etest was suboptimal. For both disc diffusion assays, use of current break points was inadequate to detect vancomycin resistance for isolates carrying the vanB gene. Inspection of the inhibition zone for a diffuse edge, as recommended, accurately predicted presence of the vanB gene. [source]