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Antibiotic Disc

The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform

Pete Smith – 1st expert on this subject based on the ideXlab platform

  • effect of incubation temperature and time on the precision of data generated by Antibiotic Disc diffusion assays
    Journal of Fish Diseases, 2015
    Co-Authors: Pete Smith, Goran Kronvall

    Abstract:

    : The influence on the precision of Disc diffusion data of the conditions under which the tests were performed was examined by analysing multilaboratory data sets generated after incubation at 35 °C for 18 h, at 28 °C for 24 h and 22 °C for 24 h and 48 h. Analyses of these data sets demonstrated that precision was significantly and progressively decreased as the test temperature was reduced from 35 to 22 °C. Analysis of the data obtained at 22 °C also showed the precision was inversely related to the time of incubation. Temperature and time related decreases in precision were not related to differences in the mean zone sizes of the data sets obtained under these test conditions. Analysis of the zone data obtained at 28 and 22 °C as single laboratory sets demonstrated that reductions of incubation temperature resulted in significant increases in both intralaboratory and interlaboratory variation. Increases in incubation time at 22 °C were, however, associated with statistically significant increases in interlaboratory variation but not with any significant increase in intralaboratory variation. The significance of these observations for the establishment of the acceptable limits of precision of data sets that can be used for the setting of valid epidemiological cut-off values is Discussed.

  • use of normalised resistance analyses to set interpretive criteria for Antibiotic Disc diffusion data produce by aeromonas spp
    Aquaculture, 2012
    Co-Authors: Pete Smith, Tamar Schwarz, David W Vernerjeffreys

    Abstract:

    Abstract Normalised resistance interpretive (NRI) analysis was applied to the development of interpretive criteria for Antibiotic Disc diffusion zones of mesophilic Aeromonas spp. Minimum quantitative and qualitative properties of data sets from which normalised resistance interpretation could generate acceptable cut-off values were established by examining published data that had been used to set the epidemiological cut-off values for bacteria of human and aquatic interest. Applying these criteria to Disc diffusion data generated in a previous study of 129 mesophilic Aeromonas spp. isolated from pet fish, demonstrated that normalised resistance interpretation was capable of generating acceptable cut-off values for seven (erythromycin ≥ 8 mm, gentamicin ≥ 18 mm, moxalactam ≥ 32 mm, oxytetracycline ≥ 21 mm, streptomycin, ≥ 20 mm tetracycline ≥ 28 mm, and trimethoprim/sulfamethoxazole ≥ 26 mm) of the agents tested. This analysis demonstrated, with respect to these agents, that a single set of interpretive criteria could be developed for application to data generated from all the Aeromonads studied. Provisional cut-off values were generated for three other agents (chloramphenicol ≥ 35 mm, florfenicol ≥ 35 mm and furazolidone ≥ 23 mm). The distribution of zone sizes for these agents showed an apparent bimodality in the high-zone end. As a result, the question of whether, for these three agents, a single set of interpretive criteria could be validly set for all Aeromonads could not be resolved. With respect to the five quinolone agents studied, a cut-off value could only be estimated for oxolinic acid. Because of the high frequency of resistance to quinolones in the strain set, this value (≥ 32 mm) should be treated as a provisional estimate. With respect to some agents, strains manifesting a low-level resistant phenotype, zones ≤ 8 mm smaller than the wild-type cut-off, represented a significant proportion of the strains classified as non wild-type. The difficulties that these frequencies of low-level resistance would present for attempts to set and apply universal, laboratory-independent interpretive criteria are Discussed.

Goran Kronvall – 2nd expert on this subject based on the ideXlab platform

  • effect of incubation temperature and time on the precision of data generated by Antibiotic Disc diffusion assays
    Journal of Fish Diseases, 2015
    Co-Authors: Pete Smith, Goran Kronvall

    Abstract:

    : The influence on the precision of Disc diffusion data of the conditions under which the tests were performed was examined by analysing multilaboratory data sets generated after incubation at 35 °C for 18 h, at 28 °C for 24 h and 22 °C for 24 h and 48 h. Analyses of these data sets demonstrated that precision was significantly and progressively decreased as the test temperature was reduced from 35 to 22 °C. Analysis of the data obtained at 22 °C also showed the precision was inversely related to the time of incubation. Temperature and time related decreases in precision were not related to differences in the mean zone sizes of the data sets obtained under these test conditions. Analysis of the zone data obtained at 28 and 22 °C as single laboratory sets demonstrated that reductions of incubation temperature resulted in significant increases in both intralaboratory and interlaboratory variation. Increases in incubation time at 22 °C were, however, associated with statistically significant increases in interlaboratory variation but not with any significant increase in intralaboratory variation. The significance of these observations for the establishment of the acceptable limits of precision of data sets that can be used for the setting of valid epidemiological cut-off values is Discussed.

David W Vernerjeffreys – 3rd expert on this subject based on the ideXlab platform

  • use of normalised resistance analyses to set interpretive criteria for Antibiotic Disc diffusion data produce by aeromonas spp
    Aquaculture, 2012
    Co-Authors: Pete Smith, Tamar Schwarz, David W Vernerjeffreys

    Abstract:

    Abstract Normalised resistance interpretive (NRI) analysis was applied to the development of interpretive criteria for Antibiotic Disc diffusion zones of mesophilic Aeromonas spp. Minimum quantitative and qualitative properties of data sets from which normalised resistance interpretation could generate acceptable cut-off values were established by examining published data that had been used to set the epidemiological cut-off values for bacteria of human and aquatic interest. Applying these criteria to Disc diffusion data generated in a previous study of 129 mesophilic Aeromonas spp. isolated from pet fish, demonstrated that normalised resistance interpretation was capable of generating acceptable cut-off values for seven (erythromycin ≥ 8 mm, gentamicin ≥ 18 mm, moxalactam ≥ 32 mm, oxytetracycline ≥ 21 mm, streptomycin, ≥ 20 mm tetracycline ≥ 28 mm, and trimethoprim/sulfamethoxazole ≥ 26 mm) of the agents tested. This analysis demonstrated, with respect to these agents, that a single set of interpretive criteria could be developed for application to data generated from all the Aeromonads studied. Provisional cut-off values were generated for three other agents (chloramphenicol ≥ 35 mm, florfenicol ≥ 35 mm and furazolidone ≥ 23 mm). The distribution of zone sizes for these agents showed an apparent bimodality in the high-zone end. As a result, the question of whether, for these three agents, a single set of interpretive criteria could be validly set for all Aeromonads could not be resolved. With respect to the five quinolone agents studied, a cut-off value could only be estimated for oxolinic acid. Because of the high frequency of resistance to quinolones in the strain set, this value (≥ 32 mm) should be treated as a provisional estimate. With respect to some agents, strains manifesting a low-level resistant phenotype, zones ≤ 8 mm smaller than the wild-type cut-off, represented a significant proportion of the strains classified as non wild-type. The difficulties that these frequencies of low-level resistance would present for attempts to set and apply universal, laboratory-independent interpretive criteria are Discussed.