A customer from (b)(6) reported there was no growth for two isolates from the same transplant patient, when using chromid® carba smart (lot 1006515680).We performed an investigation on the issue as described below.A review of manufacturing quality control records confirmed lot 1006515680 was released within specifications.During manufacturing and qc testing, there was no non-conformity or deviation recorded on this lot number.Testing included a retention sample of the lot and two other lots (one close to expiration and a fresh lot), including all positive control strains used during standard testing.Plates were incubated at 33-37ºc and incubated up to 18-24 hours.Lot 1006515680 - expired 05aug2018, and complaint time of the inoculation was (b)(6) 2018.Fresh lot 1006769620 exp: 27nov2018.Similar to complaint lot 1006570080 exp: 27aug2018.Routine qc strains, gave results within specifications equivalents to those ones obtained when product was released.All positive control strains were perfectly grown.E.Coli baa-2523 and e.Coli bba -2452 produced the expected colony appearance developing as spontaneous pink to burgundy coloration, producing beta-glucuronidase and beta-galactosidase.Klebsiella spp and serratia marcescens 1008091 produced the expected colony appearance developing as spontaneous bluish-green to bluish grey coloration producing beta]-glucosidase ( beta-glu).Proteus rettgeri 1103204 develops as spontaneous diffuse brown coloration of strains producing deaminase.There were no differences regarding the numeration, size of colony and color.The findings were expected and within acceptance criteria.A review of complaints registered for the impacted lot number 1006515680 since release date 28may2018, indicated no other complaints were recorded for this batch.Conclusion the customer's issue could not be confirmed.Routine qc testing to validate media fertility ( customer strain was not possible to test) showed results were within the acceptance criteria.In this investigation, we confirmed that the media was highly sensitive, as all cpe strains were perfectly grown, not producing false negative reaction.The false negatives observed by the customer could be linked to strain variability: strain variability: detection of such strain may be particularly problematic due to low carbapenemase production , showing a borderline resistant, therefore, for any further investigation, we would need the customer's strain and plates.The chromid® carba smart lot 1006515680 performed as expected.
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