An internal investigation was performed for a misidentification of staphylococcus lugdunensis as leuconostoc mesenteroides for two patient isolates with the vitek® 2 gp id test kit.The customer submitted the two gram positive isolates for vitek 2 evaluation.Both isolates were subcultured and tested on the customer gp id lots and a random gp lot.Vitek ms was also performed.For both isolates, an excellent id of s.Lugdunensis was obtained on all cards tested.Vitek ms also identified both isolates as s.Lugdunensis, with a 99.9% confidence value.A comparison of reaction results for customer cards giving an identification of l.Mesenteroides against expected reaction results for s.Lugdunensis revealed eight (8) atypical negative results (adh1, pyra, dmal, ilatk, dmne, mbdg, o129r, sac) that led to the incorrect call.A comparison of reaction results for customer cards giving an identification of s.Lentus against expected reaction results for s.Lugdunensis revealed one (1) atypical positive result (amy) that led to the incorrect call.An increased number of atypical reactions can indicate contamination, mixed culture, use of non-recommended media, user set up error, or an atypical strain.A complaint search against gp card lots 2420735203 and 2420668403 did not indicate any issues for these lots.The vitek 2 gp id cards performed as expected and no further action is necessary.
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