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Title: Response to Letter on Immunoassays for Field Screening of Bacillus anthracis and Ricin

Abstract

This is a response to the Letter on Immunoassays for Field Screening of Bacillus anthracis and ricin.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1378026
Report Number(s):
PNNL-SA-124365
Journal ID: ISSN 2326-5094; 400904120
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Health Security; Journal Volume: 15; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES

Citation Formats

Ozanich, Richard M., Bartholomew, Rachel A., and Bruckner-Lea, Cynthia J. Response to Letter on Immunoassays for Field Screening of Bacillus anthracis and Ricin. United States: N. p., 2017. Web. doi:10.1089/hs.2017.0011.resp.
Ozanich, Richard M., Bartholomew, Rachel A., & Bruckner-Lea, Cynthia J. Response to Letter on Immunoassays for Field Screening of Bacillus anthracis and Ricin. United States. doi:10.1089/hs.2017.0011.resp.
Ozanich, Richard M., Bartholomew, Rachel A., and Bruckner-Lea, Cynthia J. Sat . "Response to Letter on Immunoassays for Field Screening of Bacillus anthracis and Ricin". United States. doi:10.1089/hs.2017.0011.resp.
@article{osti_1378026,
title = {Response to Letter on Immunoassays for Field Screening of Bacillus anthracis and Ricin},
author = {Ozanich, Richard M. and Bartholomew, Rachel A. and Bruckner-Lea, Cynthia J.},
abstractNote = {This is a response to the Letter on Immunoassays for Field Screening of Bacillus anthracis and ricin.},
doi = {10.1089/hs.2017.0011.resp},
journal = {Health Security},
number = 2,
volume = 15,
place = {United States},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}
  • The goal of this testing was to evaluate the ability of currently available commercial off-the-shelf (COTS) biological indicator tests and immunoassays to detect Bacillus anthracis (Ba) spores and ricin. In general, immunoassays provide more specific identification of biological threats as compared to indicator tests [3]. Many of these detection products are widely used by first responders and other end users. In most cases, performance data for these instruments are supplied directly from the manufacturer, but have not been verified by an external, independent assessment [1]. Our test plan modules included assessments of inclusivity (ability to generate true positive results), commonlymore » encountered hoax powders (which can cause potential interferences or false positives), and estimation of limit of detection (LOD) (sensitivity) testing.« less
  • There is little published data on the performance of hand-portable polymerase chain reaction (PCR) instruments that could be used by first responders to determine if a suspicious powder contains a potential biothreat agent. We evaluated five commercially available hand-portable PCR instruments for detection of Bacillus anthracis (Ba). We designed a cost-effective, statistically-based test plan that allows instruments to be evaluated at performance levels ranging from 0.85-0.95 lower confidence bound (LCB) on the probability of detection (POD) at confidence levels of 80-95%. We assessed specificity using purified genomic DNA from 13 Ba strains and 18 Bacillus near neighbors, interference with 22more » common hoax powders encountered in the field, and PCR inhibition when Ba spores were spiked into these powders. Our results indicated that three of the five instruments achieved >0.95 LCB on the POD with 95% confidence at test concentrations of 2,000 genome equivalents/mL (comparable to 2,000 spores/mL), displaying more than sufficient sensitivity for screening suspicious powders. These instruments exhibited no false positive results or PCR inhibition with common hoax powders, and reliably detected Ba spores spiked into common hoax powders, though some issues with instrument controls were observed. Our testing approach enables efficient instrument performance testing to a statistically rigorous and cost-effective test plan to generate performance data that will allow users to make informed decisions regarding the purchase and use of biodetection equipment in the field.« less
  • The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest formore » vinyl tile (50.8% with BAS and 40.2% with BG) and the highest for glass (92.8% with BAS and 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG; values increased as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent article.« less
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