A customer in (b)(6) reported the occurrence of false susceptible flucytosine results for a candida norvegensis eeq strain in association with the vitek® 2 ast-ys07 test kit (ref 414967).Vitek® 2 provided the following result: flucytosine mic = 4 (susceptible), expected result is resistant.Per the customer, they tested the strain twice and received the same result.There is no indication or report from the laboratory that the discrepant result led to any adverse event related to any patient's state of health.There was no patient associated with this survey isolate.A biomérieux internal investigation will be initiated.
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This report was initially submitted in response to a customer in (b)(6) reporting the occurrence of false susceptible flucytosine results for a candida norvegensis eeq survey strain in association with the vitek® 2 ast-ys07 test kit (ref 414967).Vitek® 2 provided the following result: flucytosine mic = 4 (susceptible).An internal biomérieux investigation was performed that included testing for both fluconazole (flu) and flucytosine (fct) results on vitek® 2 ast-ys07 cards with a strain of candida norvegensis from this biologie prospective survey (mycology 2017- sample 3a).Id testing : identification was confirmed to candida norvegensis on yst card (lot 2430356103) ast testing: · reference method to determine the intended result for fluconazole and flucytosine: broth microdilution, method used to develop the formularies "flu01n" / "fct01n" (in ast-ys07 card).· flu mic = 16 mg/l intermediate · fct mic = 8 mg/l intermediate interpretation according to vitek 2 breakpoints in v7.01 : fda 2009 breakpoints for candida / fluconazole s =8 - i 16-32 - r >/=64.Fda 2012 breakpoints for candida / flucytosine : s =4 - i 8-16 - r >/=32.Note: for antifungals, essential agreement between vitek® 2 card and reference method mics is +/- 2 doubling dilutions.· products & system incriminated: -*ast -ys07 on vitek 2 v7.01 three (3) vitek 2 ast-ys07 card lots were tested from sabouraud dextrose agar (sda).Vitek 2 gave the following results: **flu mic = 16 mg/l i on the three (3) lots tested **fct mic = 4 mg/l s on two (2) lots , 8 mg/l i on the third lot.The vitek 2 results are within essential agreement with the reference mic within +/- 1 doubling dilution.Note: according to fsca 2509 (released april 2015), fct results from ast-ys07 cards (fct01n formulation) should not be reported for any organism.Conclusion: -we duplicated the customer results on ast-ys07 cards (mic flu=16 mg/l i and fct mic=4 mg/l s).-the vitek 2 ast-ys07 cards perform as intended.The vitek 2 values are within essential agreement with the reference results obtained in bmd.-the reference mic for both fluconazole and flucytosine are in the middle of the breakpoints, so the strain can be susceptible or resistant within +/- 2 doubling dilutions.-->borderline strain.
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