A customer in (b)(6) reported the occurrence of false susceptible fluconazole and false susceptible flucytosine results for a candida norvegensis eeq strain in association with the vitek® 2 ast-ys08 test kit (ref 420739).Vitek® 2 provided the following results: fluconazole mic = 8 (susceptible), expected result is resistant.Flucytosine mic = 4 (susceptible), expected result is resistant.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 strain in association with the vitek® 2 ast-ys08 test kit (ref 420739).Vitek® 2 obtained flucytosine mic = 4 (susceptible).An internal biomérieux investigation was performed that included testing for both fluconazole (flu) and flucytosine (fct) results with a strain of candida norvegensis on vitek® 2 ast-ys08 cards.This strain is from a biologie prospective survey (mycology 2017- sample 3a).Id testing : identification was confirmed to candida norvegensis on vitek 2 yst id card (lot 2430356103).Ast testing: · reference method to determine the intended result for fluconazole and flucytosine: broth microdilution, method used to develop the formularies "flu02n" / "fct02n" (in ast-ys08 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 -ys08 on vitek 2 v7.01 three (3) vitek 2 ast-ys08 lots were tested from sabouraud dextrose agar (sda).Vitek 2 gave the following results on the three (3) lots tested: **flu mic = 8 mg/l susceptible **fct mic = 4 mg/l susceptible the vitek 2 results are within essential agreement with the reference mic within +/- 1 doubling dilution.Conclusion: -the customer results were duplicated on the ast-ys08 cards (mic flu= 8 mg/l s and fct mic=4 mg/l s).-the vitek 2 ast-ys08 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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