The RAZOR EX Anthrax Air Detection System, developed by Idaho Technology, Inc. (ITI), is a qualitative method for the detection of Bacillus anthracis spores collected by air collection devices. This system comprises a DNA extraction kit, a freeze-dried PCR reagent pouch, and the RAZOR EX real-time PCR instrument. Each pouch contains three assays, which distinguish potentially virulent B. anthracis from avirulent B. anthracis and other Bacillus species. These assays target the pXO1 and pXO2 plasmids and chromosomal DNA. When all targets are detected, the instrument makes an "anthrax detected" call, meaning that virulence genes of the anthrax bacillus are present. This report describes results from AOAC Method Developer (MD) and Independent Laboratory Validation (ILV) studies, which include matrix, inclusivity/exclusivity, environmental interference, upper and lower LOD of DNA, robustness, product consistency and stability, and instrument variation testing. In the MD studies, the system met the acceptance criteria for sensitivity and specificity, and the performance was consistent, stable, and robust for all components of the system. For the matrix study, the acceptance criteria of 95/96 expected calls was met for three of four matrixes, clean dry filters being the exception. Ninety-four of the 96 clean dry filter samples tested gave the expected calls. The nucleic acid limit of detection was 5-fold lower than AOAC's acceptable minimum detection limit. The system demonstrated no tendency for false positives when tested with Bacillus cereus. Environmental substances did not inhibit accurate detection of B. anthracis. The ILV studies yielded similar results for the matrix and inclusivity/exclusivity studies. The ILV environmental interference study included environmental substances and environmental organisms. Subsoil at a high concentration was found to negatively interfere with the pXO1 reaction. No interference was observed from the environmental organisms. The nucleic acid LOD, however, was 10 times higher (1 pg/reaction, equivalent to about 200 spores) than that found in the MD study. These results indicate that the RAZOR System is a sensitive and specific system that accurately identifies B. anthracis in aerosol matrixes and in the presence of interfering substances, and that the method can be performed by an independent laboratory and achieve similar results.
Background Antimicrobial resistance (AMR) surveillance is critical in informing strategies for infection control in slowing the spread of resistant organisms and for antimicrobial stewardship in the care of patients. However, significant challenges exist in timely and comprehensive AMR surveillance. Methods Using BioFire Pneumonia and Blood Culture 2 Panels data from BioFire Syndromic Trends (Trend), a cloud-based population surveillance network, we described the detection rate of AMR among a US cohort. Data was included from 2019-2021 for gram-positive and -negative organisms and their related AMR genomic resistant determinants as well as for detections of Candida auris. Regional and between panel AMR detection rate differences were compared. Additionally, AMR codetections and detection rate per organism were evaluated for gram-negative organisms. Results A total of 26,912 tests were performed, primarily in the Midwest. Overall, AMR detection rate was highest in the South and more common for respiratory specimens than blood. MRSA and VRE detection rates were 34.9% and 15.9%, respectively, while AMR for gram-negative organisms was lower with 7.0% CTX-M and 2.9% carbapenemases. Additionally, 10 mcr-1 and four C. auris detections were observed. For gram-negative organisms, K. pneumoniae and E. coli were most likely to be detected with an AMR gene, and of gram-negative organisms, K. pneumoniae was most often associated with two or more AMR genes. Conclusion Our study provides important in-depth evaluation of the epidemiology of AMR among respiratory and blood specimens for gram-positive and -negative organism in the United States. The Trend surveillance network allows for near-real time surveillance of AMR.
The RAZOR EX Anthrax Air Detection System was validated in a collaborative study for the detection of Bacillus anthracis in aerosol collection buffer. Phosphate-buffered saline was charged with 1 mg/mL standardized dust to simulate an authentic aerosol collection sample. The dust-charged buffer was spiked with either B. anthracis Ames at 2000 spores/mL or Bacillus cereus at 20 000 spores/mL. Twelve collaborators participated in the study, with four collaborators at each of three sites. Each collaborator tested 12 replicates of B. anthracis in dust-charged buffer and 12 replicates of B. cereus in dust-charged buffer. All samples sets were randomized and blind-coded. All collaborators produced valid data sets (no collaborators displayed systematic errors) and there was only one invalid data point. After unblinding, the analysis revealed a cross-collaborator probability of detection (CPOD) of 1.00 (144 positive results from 144 replicates, 95% confidence interval 0.975-1.00) for the B. anthracis samples and a CPOD of 0.00 (0 positive results from 143 replicates, 95% confidence interval 0.00-0.0262) for the B. cereus samples. These data meet the requirements of AOAC Standard Method Performance Requirement 2010.003, developed by the Stakeholder Panel on Agent Detection Assays.
BackgroundRapid identification of causative agents from positive blood culture (PBC) can aid earlier targeted therapy, as well as reduce mortality, length of stay, and costs associated with systemic infections. The BioFire® Blood Culture Identification 2 (BCID2) Panel being developed by BioFire Diagnostics, LLC, aims to maintain or improve the performance of the BioFire® FilmArray® Blood Culture Identification (BCID) Panel with updated and novel assays (15 new analytes: six antimicrobial resistance (AMR), six bacterial, and three fungal analytes). The performance of an RUO BioFire BCID2 Panel during a prospective pilot study is compared with standard of care (SoC), as well as independent PCR comparator assay (compPCR) results.MethodsTwo pilot sites enrolled de-identified PBC (<24 hours post-positivity) for which clinician-ordered SoC tests had been performed. Aliquots of residual PBC and isolates were frozen for compPCR testing of AMR markers and discrepancy resolution. 100 aerobic PBC (A-PBC) and 85 anaerobic PBC (AN-PBC) were tested with the BioFire BCID2 Panel; 70 A-PBCs and 56 AN-PBCs were concurrently tested on BioFire BCID Panel. Also, isolates from PBCs positive for AMR markers were tested using compPCR.ResultsThe BioFire BCID2 Panel results matched SoC results in 176/177 detections from 100 A-PBC, and in 167/168 detections from 85 AN-PBC. Both BioFire panels detected Candida glabrata and Candida parapsilosis from an A-PBC with only C. parapsilosis SOC result; interestingly, C. glabrata was detected by SoC in the paired AN-PBC. False-positive Bacteroides fragilis detection in an AN-PBC was resolved favorably by compPCR. Two patient samples, positive in both A-PBC and AN-PBC by SoC, were not detected by either the Staphylococcus epidermidis or the Staphylococcus spp. assays on the BioFire BCID2 Panel. All 26 AMR marker detections in both types of PBC were concordant with either SoC or compPCR results.ConclusionWith an expanded menu, >99% specificity, and >97% sensitivity, the BioFire BCID2 Panel is expected to provide rapid and accurate results for key pathogens associated with systemic infections, as well as important AMR markers.RUO products used in this study have not been evaluated by the FDA or other regulatory agencies for In Vitro Diagnostic use.Disclosures U. Spaulding, BioFire Diagnostics, LLC: Employee, Salary. J. Stone, BioFire Diagnostics, LLC: Employee, Salary. K. Koch, BioFire Diagnostics, LLC: Employee, Salary. J. Antosch, BioFire Diagnostics, LLC: Employee, Salary. M. Jones, BioFire Diagnostics, LLC: Employee, Salary. Z. Lu, BioFire Diagnostics, LLC: Employee, Salary. T. Todorov, BioFire Diagnostics, LLC: Employee, Salary. S. Kerr, BioFire Diagnostics, LLC: Employee, Salary. K. Holmberg, BioFire Diagnostics, LLC: Employee, Salary. M. Rogatcheva, BioFire: Employee, Salary.
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