Evaluation of Immunoassays and General Biological Indicator Tests for Field Screening ofBacillus anthracisand Ricin

Abstract

There is little published data on the performance of biological indicator tests and immunoassays that could be used by first responders to determine if a suspicious powder contains a potential biothreat agent. We evaluated a range of biological indicator tests, including 3 protein tests, 2 ATP tests, 1 DNA test, and 1 FTIR spectroscopy instrument for their ability to screen suspicious powders for Bacillus anthracis (B. anthracis) spores and ricin. We also evaluated 12 immunoassays (mostly lateral flow immunoassays) for their ability to screen for B. anthracis and ricin. We used a cost-effective, statistically based test plan that allows instruments to be evaluated at performance levels ranging from 0.85 to 0.95 lower confidence bound of the probability of detection at confidence levels of 80% to 95%. We also assessed interference with 22 common suspicious powders encountered in the field. The detection reproducibility for the biological indicators was evaluated at 108 B. anthracis spores and 62.5 μg ricin, and the immunoassay detection reproducibility was evaluated at 107 spores/mL (B. anthracis) and 0.1 μg/mL (ricin). Seven out of 12 immunoassays met our most stringent criteria for B. anthracis detection, while 9 out of 12 met our most stringent test criteria for ricin detection. Most of the immunoassays also detected ricin in 3 different crude castor seed preparations. Our testing results varied across products and sample preparations, indicating the importance of reviewing performance data for specific instruments and sample types of interest for the application in order to make informed decisions regarding the selection of biodetection equipment for field use.

A Rapid, Sensitive, and Portable Biosensor Assay for the Detection of Botulinum Neurotoxin Serotype A in Complex Food Matrices

“…The sample preparation time is variable depending on the type of sample matrix and this will add more time to any assay. The CANARY ® Zephyr system is also portable, deployable to potentially manufacturing or processing centers because it consists of a laptop, a small centrifuge, and a small luminometer that can fit in a suitcase but still fit on a small bench top space [ 33 ]. Yet, its portability does not sacrifice utility, as the assay also uses small volumes (50 μL) to facilitate multiple sample analysis for precious samples.…”

“…Recently, the CANARY ® Zephyr system was evaluated against a variety of immunoassays (mostly lateral flow) as well as other biological indicator tests using the potential bioterror threats Bacillus anthracis and ricin. The study found that the limit of detection of ricin was 3.0 ng/mL and 10 3 spores/mL for B.anthracis [ 33 ]. The authors found that compared against various commercially available kits, the CANARY ® Zephyr platform was 4 orders of magnitude more sensitive for detecting B. anthracis and was the most sensitive for ricin.…”

A Rapid, Sensitive, and Portable Biosensor Assay for the Detection of Botulinum Neurotoxin Serotype A in Complex Food Matrices

“…This study has found that the assay is rapid: (< 40 min) from the addition of immunomagnetic capture beads to the reaction matrix to the read out of luminescence and final determination of positive or negative for the sample tested, which is better than most traditional methods. The CANARY ® Zephyr system is also portable, suitable for field-deployable because it consists of a laptop, a small centrifuge, and a small luminometer that can fit in a suitcase [33]. Yet, its portability does not sacrifice utility, as the assay also uses small volumes (50 μL) to facilitate multiple sample analysis for precious samples.…”

“…Recently, the CANARY ® Zephyr system was evaluated against a variety of immunoassays (mostly lateral flow) as well as other biological indicator tests using the potential bioterror threats Bacillus anthracis and ricin. The study found that the limit of detection of ricin was 3 ng/mL and 10 3 spores/mL for B.anthracis [33]. The authors found that compared to all of the other commercially available kits, the CANARY ® Zephyr platform was 4 orders of magnitude more sensitive for detecting B. anthracis and was the most sensitive for ricin.…”

Unbiased Strain-Typing of Arbovirus Directly from Mosquitoes Using Nanopore Sequencing: A Field-forward Biosurveillance Protocol

“…Additionally, metagenomic sequencing on second-generation sequencing technology typically requires more than a 24 hour time investment on non-portable machines. Consequently, field-forward biosurveillance has been limited to primarily PCR-based assays 19–21 or antibody hybridization technologies 22–25 , which have been the first molecular biology hardware to reach a portable, hand-held form factor.…”