A customer in (b)(6) notified biomérieux of obtaining a false resistant ceftriaxone result in association with the etest® ceftriaxone 256 tx m100 ww (ref.423772).The customer had previously reported false resistant ceftriaxone results when testing four (4) isolates of proteus hauseri from a single patient using the vitek® 2 ast-n390 test kit (ref.423340, lot 1401751104) and a susceptible ceftriaxone result with etest® (ref.423772).Refer to (b)(4).These isolates associated with (b)(4) were submitted for investigation and tested using the broth micro dilution (bmd) test method.The bmd test method obtained a ceftriaxone resistant minimum inhibitory concentration (mic) results.These results aligned with the vitek® 2 ast-n390 test kit resistant results and conflicted with the customer's susceptible etest mic= 0.12 result.Therefore, this complaint (b)(4) was initiated to track the activities related to this new etest malfunction.The awareness date of the false susceptible etest result is (b)(6) 2021, when the result of the submitted isolate was available through the investigation result.There is no indication or report from the customer that this event led to any adverse event related to any patient's state of health.Note: reference 423772 is not registered in the united states.The u.S.Similar device is product reference 412300.
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A customer in canada obtained a false resistant ceftriaxone result in association with the etest® ceftriaxone 256 tx m100 ww (ref.423772).Investigation retained sample testing: retained samples of the lot number 1008559340 were tested in parallel with one internal lot number used as a reference lot (reference (b)(4), lot 1008691840, expiry date on 26 aug 2023).The tests were performed using the quality control (qc) strains escherichia coli atcc® 25922¿, staphylococcus aureus atcc® 29213¿, pseudomonas aeruginosa atcc® 27853¿, and streptococcus pneumoniae atcc® 49619¿, according to the qc protocol used for the release of each lot number.The qc results obtained for the four strains tested are within the expected range for the investigated etest lot and the reference etest lot.The mic values obtained with the qc strains during the investigation are the following : escherichia coli atcc® 25922¿ : mic values at 0.064 g/ml (expected range : 0.032 ¿ 0.125 g/ml).Staphylococcus aureus atcc® 29213¿ : mic values at 4 g/ml (expected range : 1 ¿ 8 g/ml).Pseudomonas aeruginosa atcc® 27853¿ : mic values between 12 and 16 g/ml (expected range : 6 ¿ 32 g/ml).Streptococcus pneumoniae atcc® 49619¿ : mic values between 0.064 and 0.094 g/ml (expected range : 0.032 ¿ 0.125 g/ml).Returned sample analysis: tests were performed with the proteus hauseri patient strain submitted by the customer.The identification of the provided strain was confirmed internally with vitek2 gn id card as a proteus hauseri.The strain was tested with the agar dilution (ad) methodology (method used for the development of etest® tx 256), with the impacted etest® tx 256 lot (lot number 1008559340) and with etest® tx 256 lot number 1008691840 used as a reference lot.Ceftriaxone enterobacterales clsi 2021 breakpoints were used to categorize the mic values : [s = 1 - r = 4].The following results were obtained : mic obtained with ad method : 0.12 g/ml (susceptible).Mic obtained with etest® tx 256 lot number 1008559340 : 0.03 g/ml (susceptible).Mic obtained with etest® tx 256 lot number 1008691840 : 0.06 g/ml (susceptible).The etest® tx 256 lot number 1008559340 showed an essential agreement error compared to the reference mic without any category error.The etest® tx 256 lot number 1008691840 remains within essential agreement compared to the reference mic without any category error.Based on these results, we can conclude that etest® tx 256 susceptible results obtained by the customer are reproduced during the investigation but they remain within category agreement compared to the agar dilution.Complaint database review on the 19th of january 2022, no other complaints was registered on this lot number.Conclusion the results of the quality control tests obtained during our investigation with the lot 1008559340 complied with our specifications.The etest® tx 256 susceptible results obtained by the customer are reproduced during the investigation but they remain within category agreement compared to the agar dilution.No product performance problem was observed during the investigation.
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