MAUDE Adverse Event Report: CEPHEID XPERT MRSA/SA BC; XPERT MRSA/SA BLOOD CULTURE

Catalog Number	GXMRSA/SA-BC-10
Medical Device Problem Code	False Negative Result (1225)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	12/26/2024
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
Us customer contacted cepheid to discuss discrepant results for a patient using xpert mrsa/sa bc.Sample was collected from the patient and run on xpert mrsa/sa bc on (b)(6) 2024 which resulted in mrsa negative, sa negative.This result was reported to the physician.The sample was retested on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The same sample was retested a second time on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The sample was retested a third time on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The tests were run off-label.The customer tested both the aerobic and anaerobic bottle collected from the patient, customer was unable to identify which runs correspond to which bottle outside of the initial test, which was run with the aerobic bottle.Customer reported they have validated running the off-label anaerobic bottle with xpert mrsa/sa bc.Sample was also stored at 35 degrees c in the bactec incubator between tests.Bottles were placed on the incubator; the aerobic bottle rang positive at 16:17 on (b)(6) 2024.Bottle was immediately removed from the incubator.Gram stain was performed and gram-positive cocci in clusters was observed.Customer processed the samples per the pi.Culture was performed using the remel bap, chocolate and macconkey plates.An organism grew and was identified on the walkaway 96 at 99.99% staph aureus on (b)(6) 2024.No mixed culture was observed.Susceptibility testing was performed on the walkaway (b)(6) 2024 which resulted as susceptible to oxacillin.There is no known death, injury or deterioration in health related to the discrepancy.Retests performed due to the discrepancy between the initial gx result and culture method.It is suspected that the false-negative result is due to a mutation in the region targeted by the spa primers and probe that is preventing amplification.This is also corroborated by the strong amplification of the scc target by the xpert mrsa/sa bc, suggesting the presence of the remnats of the s.Aureus orfx/sccmec junction region.The robust scc cts are indicative of an empty cassette: possibly and mrsa that lost the meca gene due to a partial excision of the sccmec element.These events sometimes can include adjacent genes such as spa.Cepheid has received the isolate for sequencing to identify the specific mutation/deletion in spa and determine the strain type.At this point, the investigation is still ongoing.At this time, no patient harm has been reported.A supplemental report will be submitted once sequencing has been completed.Note for section h3 device evaluated by manufacturer - answer of no is due to the single use of the xpert mrsa/sa bc test and the unavailability of that product lot to be returned to cepheid.
Event or Problem Description
Us customer contacted cepheid to discuss discrepant results for a patient using xpert mrsa/sa bc.Sample was collected from the patient and run on xpert mrsa/sa bc on (b)(6) 2024 which resulted in mrsa negative, sa negative.This result was reported to the physician.The sample was retested on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The same sample was retested a second time on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The sample was retested a third time on (b)(6) 2024 using xpert mrsa/sa bc which resulted in mrsa negative, sa negative.This result was reported to the physician.The tests were run off-label.The customer tested both the aerobic and anaerobic bottle collected from the patient, customer was unable to identify which runs correspond to which bottle outside of the initial test, which was run with the aerobic bottle.Customer reported they have validated running the off-label anaerobic bottle with xpert mrsa/sa bc.Sample was also stored at 35 degrees c in the bactec incubator between tests.Bottles were placed on the incubator; the aerobic bottle rang positive at 16:17 on (b)(6) 2024.Bottle was immediately removed from the incubator.Gram stain was performed and gram-positive cocci in clusters was observed.Customer processed the samples per the pi.Culture was performed using the remel bap, chocolate and macconkey plates.An organism grew and was identified on the walkaway 96 at 99.99% staph aureus on (b)(6) 2024.No mixed culture was observed.Susceptibility testing was performed on the walkaway (b)(6)2024 which resulted as susceptible to oxacillin.There is no known death, injury or deterioration in health related to the discrepancy.Retests performed due to the discrepancy between the initial gx result and culture method.
Additional Manufacturer Narrative
Cepheid has completed sequencing of the isolate, whole genome sequencing (wgs) analysis confirmed that an 8bp deletion in the region of the spa gene targeted by the spa probe prevented detection by the assay (fwd and rev primers were able to bind).The isolate is spa type t008/st8 and confirmed to be meca-negative (mssa).This is a widespread genotype (cc5 and cc8 are the two dominant clones in the us) and as a result, we have seen a few with spa mutations before.The root cause for the discrepancy is 8bp deletion, a different strain type.

• Brand Name: XPERT MRSA/SA BC
• Common Device Name: XPERT MRSA/SA BLOOD CULTURE
• Manufacturer (Section D): CEPHEID; 904 e caribbean dr; sunnyvale CA 94089
• Manufacturer (Section G): CEPHEID; 904 e caribbean dr; sunnyvale CA 94089
• Manufacturer Contact: somesh lalithraj ; 904 e caribbean dr; sunnyvale, CA 94089 ; 4085488951
• MDR Report Key: 21246440
• Report Number: 3004530258-2024-00027
• Device Sequence Number: 15586763
• Product Code: NQX
• UDI-Device Identifier: 07332940000141
• UDI-Public: 07332940000141
• Combination Product (Y/N): N
• Initial Reporter State: AR
• Initial Reporter Country: US
• PMA/510(K) Number: K130894
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional,User Facility
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 02/25/2025

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Expiration Date: 01/18/2026
• Device Catalogue Number: GXMRSA/SA-BC-10
• Device Lot Number: 1001430290
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 12/27/2024
• Supplement Date Received by Manufacturer: 01/28/2025
• Initial Report FDA Received Date: 01/27/2025
• Supplement Report FDA Received Date: 02/25/2025
• Was Device Evaluated by Manufacturer? (Y/N): No
• Date Device Manufactured: 05/15/2024
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Patient Sex: Unknown