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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