VITEK MS Collaborative Study Outline - eBook
The FDA Clinical Trial results showed an overall percent agreement of 95.3% (5860/6151): Gram 1 negative, 94.1% (2891/3072); Gram positive, 95.9% (1926/2009); and yeast, 97.5% (1043/1070). See 2 Tables 8‐10 for raw data. For a complete list of results from the FDA Clinical Trial, the documents are 3 available online. (2) 4 The bioMérieux study results showed an overall percent agreement of 100% (193/193): Gram negative, 5 123/123 and Gram positive, 70/70. See Tables 11‐12 for raw data. 6 The combined results of the FDA and bioMérieux claimed organism studies show an overall percent 7 agreement 95.4% including all three groups of organisms tested – Gram negative (94.3%), Gram positive 8 (96.0%) and yeast (97.5%). 9 10 Independent Laboratory Validation Study 11 The bacterial strains used in this study were prepared from the culture collection of the Agriculture and 12 Food Laboratory, University of Guelph, Ontario, Canada. Strains were cultured from stocks stored at 13 −80°C in 20% glycerol. During the validaƟon study, the strains were maintained at 4°C on TSAB or 14 Trypticase Soy Agar (TSA) slants. One or more technicians prepared the cultures and a different 15 technician performed the assays on blind coded cultures. All cultures were randomized and labeled with 16 a code so that the analyst performing the assays was unaware of the type of bacterial culture present. 17 Bacterial strains were first streaked onto a TSAB and incubated overnight at 35°C. All strains were grown 18 under aerobic conditions except Campylobacter jejuni under microaerophilic conditions, and Clostridium 19 perfringens which was grown under anaerobic conditions. Well isolated colonies were then selected for 20 analysis via the VITEK‐MS protocol. Yeast strains were grown on Sabouraud Dextrose Agar at 35°C under 21 aerobic conditions, selecting well isolated colonies for analysis via the VITEK‐MS protocol. 22 For each bacterial strain, using a 1.0 μL loop, one or more colonies from the TSAB plate (ideally from 23 isolated colonies with a diameter of approximately 3 mm) were applied as a thin layer to the center of a 24 well at a designated VITEK MS‐DS position. Carefully 1.0 μl of the VITEK MS‐CHCA was added to the 25 center of each VITEK MS‐DS position with sample using a new pipette tip for each sample. The sample 26 was allowed to dry completely. The sample was then tested with the VITEK MS instrument. 29 The results of the Independent Laboratory study showed an overall percent agreement of 100% 30 including all three groups of organisms tested – Gram negative, 100% (39/39), Gram positive, 100% 31 (25/25) and yeast, 100% (5/5). There was one discordant result in the Independent Laboratory study: 32 Saccharomyces cerevisiae (VITEK MS result ‐ No identification). This result was not typical. When 33 reviewing the internal data from the FDA Clinical Study, Saccharomyces cerevisiae resulted in a 97.6% 34 agreement (41 positive out of 42 tested). The Independent Laboratory retested the S. cerevisiae as they 35 noted that a reagent was close to expiration date and could have been the cause of the No identification 36 result. Upon retest, the S. cerevisiae was identified correctly. Overall, the Independent Laboratory 37 results were in 100% agreement with the known culture identifications. 38 See Appendix 3 for summary data (Table 7) and Appendix 4 for raw data (Tables 13‐15). 27 28 Results
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Robustness Study
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