A customer from malaysia reported a misidentification of corynebacterium diphtheriae from a throat specimen in association with the vitek® 2 anc test kit (lot 2440285403).A customer first identified c.Diphtheriae with a high confidence level using api® coryne.The isolate was then sent to a second customer for confirmation using vitek® 2.The isolate was tested multiple times with the anc card, and various identifications were obtained: c.Ulcerans , low discrimination to c.Amycolatum and atopobium vaginae, unidentified, and low discrimination to c.Amycolatum and c.Diphtheriae.The first customer then retested the isolate with the bd bbl¿ crystal¿ identification system which resulted in c.Diphtheria (99%).The customer stated the result of c.Diphtheria was reported to the clinician.The customer reported that there was no impact to patient results or treatment.The local field application specialist (fas) tested the isolate at the customer site and received a low discrimination to c.Amycolatum and a.Vaginae with the vitek 2.The fas then tested the isolate at another customer site and their own lab, with vitek 2 and vitek ms instruments.The vitek 2 results were low discrimination to c.Amycolatum and a.Vaginae, and also a.Vaginae at 93%.The vitek ms result was c.Diphtheriae at 99.9%.The isolate was also tested with api coryne in duplicate, and both tests gave a doubtful profile.An investigation will be initiated.
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A customer in (b)(6) obtained a low discrimination call of corynebacterium amycolatum/atopobium vaginae or a very good identification of a.Vaginae when testing two (2) isolates on vitek® 2 anc cards.When tested on vitek® ms, an identification of corynebacterium diphtheriae was obtained, with a 99.9% confidence level.Bbl crystal also gave a 99% identification of c.Diphtheriae.Api coryne gave a doubtful profile, with a 40% identification of c.Diphtheriae.The organisms were subbed and tested on two (2) customer lots of anc cards, along with a random lot, in duplicate.Vitek® ms testing was also performed.For both isolates 911613 and 911614, a low discrimination call of c.Amycolatum/a.Vaginae was obtained on all cards tested.Vitek® ms gave an identification of c.Diphtheriae, with a 99.9% confidence value.Therefore, the final identification is c.Diphtheriae.A comparison of card reaction results for the low discrimination call of c.Amycolatum/a.Vaginae against expected reaction results for c.Diphtheriae showed three (3) atypical negative reactions (ellm, phea, tyra) that led to the incorrect call.An increased number of atypical negative results can indicate a strain with decreased viability, user set up error or an atypical strain.
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