Investigation summary : this complaint is for discrepant cpo detection of serratia marcescens when using phoenix panel nmic-306 (449292) batch number 1196720.The customer did return isolates and lab reports for investigation, however no panels were returned.To investigate, a total of six retention panels from the complaint batch were tested on a phoenix m50 instrument.The retention panels were tested using the following qc isolates: enf18981 (pseudomonas aeruginosa) and a25922 (escherichia coli).One customer returned isolate, 79768 (serratia marcescens) was tested in addition to the qc isolates.Two panels were tested per isolate and evaluated for ambler classification results.During investigation, all panels tested using isolates a25922 and customer returned 79768 did not classify as class b carbapenemase producers.All panels tested using isolates enf18981 did classify as class b carbapenemase producers as expected.This complaint is not confirmed.In addition to the quality investigation performed, r&d investigated using the customer returned isolates.Internal r&d testing did not confirm cpo false positive or class b false positive results for 2 out of 2 isolates.Serratia marcescens yielded susceptible mics to ipm, mem, etp, cza and ct on bmd.Pseudomonas aeruginosa yielded resistant mics to ipm and mem, while yielding susceptible results for cza and ct on bmd.Pseudomonas aeruginosa has intrinsic resistance to etp.Although all carbapenem microbials are resistant for pseudomonas aeruginosa, it has the potential to be a carbapenemase producing organism but cannot be confirmed without pcr testing.However, it is unlikely that both strains are carbapenemase producing organisms since mcim was negative.Furthermore, both isolates produced resistance to 3rd generation cephalosporins (caz and cro) and atm, which suggests other resistance mechanisms such as amp c beta-lactamase production and/or reduced porin expression. cloxacillin (clx) is a class c beta-lactamase inhibitor and is added in combination with mem on the cpo detect test to reduce background beta-lactamase activity that can confound the panel.It can be concluded that the cpo detect test on nmic-306 and nmic-307 panel produced false cpo positive results, because mem61d (mem+clx) well did not effectively inhibit amp c production in the strains.A review of quality notifications revealed no quality notifications for the complaint batch. a review of complaints revealed two additional complaints for the complaint batch.Complaint trending was performed and no trends were identified associated with this defect.Bd id/ast plant quality will continue to monitor for trends and take action as necessary.H3 other text : see h10.
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