An internal investigation was reported for a misidentification of staphylococcus aureus as staphylococcus pseudintermedius in association with the vitek 2 gp (gram-positive) id test kit (lot 2420686403).The customer's strain was subcultured to remel tsab agar and incubated at 35-37° in ambient atmosphere for 18-24 hours.In addition to the staphylococcus species present, it was noted that one alpha hemolytic colony was present as well, which was a likely contaminant and therefore not tested.A second subculture was performed on the staphylococcus colonies.Testing included vitek 2 gp card on the customer lot 2420686403 and a random lot, 2420587103, at s/w version 8.01 as well as vitek ms testing.911782 (15615670) was tested on the customer and random lots.Three of the four gp id cards ran gave a low discrimination identification of staph.Aureus/s.Chromogenes/s.Pseudintermedius with the fouth card giving a final low discrimination identification of staph.Aureus/s.Chromogenes.The staphylococcus was also identified via vitek ms as staphylococcus aureus with 99.9% confidence value.As the correct identification was included in the low discrimination call, vitek 2 cards are performing as intended.Review of the customer's biochemical reactions showed one atypical positive reaction (leua) for an identification of s.Aureus according to the gp knowledge base.An atypical reaction can indicate a strain with decreased viability, contamination, mixed culture, use of non-recommended media or other user set up error.
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