Strategies for Effective Improvements to the BioWatch System Proceedings of a Workshop (2018) / Chapter Skim
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Appendix I: Invited Paper: BioWatch Improvements Within Existing Biological Detection Architecture
Appendix I: Invited Paper: BioWatch Improvements Within Existing Biological Detection Architecture
Pages 191-206
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From page 191... ...
Title: Director, Knoxville Regional Laboratory Current Affiliation: Tennessee Department of Health Former Affiliation (1996-2015) : Illinois Department of Public Health 191
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From page 192... ...
Processing of filters and interrogation of DNA sequences by real-time PCR is similar for both systems. Interpretation of PCR results would also be similar, but subsequent actions based on presumptive positive results may have differed based on the differences between an Olympic setting with international attendance and an American city.
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From page 193... ...
Along these lines, a phrase heard at the Diamond Bar meeting, which some thought would become the motto of BioWatch, was "Detect to Treat." Others, however, considered such a relationship between laboratory results and public health policy to be overly simplistic and potentially disastrous. Within the next few weeks, by the time the push packs of equipment and supplies began showing up at public health laboratories, the epidemiologists and decision makers within these public health departments were looking to the BioWatch program for additional guidance in interpreting and acting on a positive laboratory result.
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From page 194... ...
If a positive reaction is observed, several repeat real-time PCRs will then be performed on the DNA preparation in question, each with an additional, different primer-probe set for the suspected agent in order to challenge and enhance overall specificity. Only if the proper combination of primer-probe sets are reactive for a given agent will a positive result be considered.
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From page 195... ...
The first step in this process is to consult with the laboratory's BioWatch director, who is the representative of the local public health jurisdiction, and the BioWatch staff. Various quality assurance measures will be undertaken, including a review of any recent work with the agent in question–either as part of a positive quality assurance filter, a proficiency testing filter, or work by either the BioWatch staff or personnel of the host laboratory.
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From page 196... ...
Initially, changes were made to increase throughput to accommodate larger jurisdictions: block shakers accommodating an entire rack of tubes were introduced, replacing individual tube shakers for bead beating; 96-well vacuum manifolds were implemented for filtration steps, replacing individual filter/centrifuge tubes; and the screening protocol was changed to allow pooling of up to three DNA lysates for the initial real-time PCR screening step, thereby conserving reagents and amplification plate utilization. However, the follow-up to a reactive screen then requires that each of the DNA lysates comprising a pool be individually tested with the full LRN primerprobe set for the agent in question.
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From page 197... ...
Nevertheless, repeat testing of initially reactive DNA lysates is still performed with the full set of LRN primer probes as used for all other environmental or clinical testing conducted through the LRN-B. Addition of Quality Assurance Measures A fundamental and necessary change to the BioWatch system was the addition of a quality assurance program.
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From page 198... ...
competency assessments of the testing staff, daily positive quality assurance filters with coded spikes simulating one or more of the test agents, regular (three times per year) proficiency testing challenges, annual internal audits, and semiannual site visits to provide an unbiased external audit of all laboratory activities.
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From page 199... ...
The BioWatch quality assurance program helps to prevent and detect such errors, but constant vigilance and efforts to vary the staff's job duties as much as possible are also an essential part of preventive actions. It has been stated by the BioWatch program that, in all its years of operation, there have been no false-positive results out of millions of PCR assays.
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From page 200... ...
As currently designed, BioWatch can only find what it's looking for. The holy grail of a biological detection system would be the virtually instantaneous detection and identification of any agent posing a biological threat.
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From page 201... ...
In any event, if the 24-hour filter or pool tested positive, then each of the individual sequential filters could be tested to determine when the positive material was encountered. While a system such as that just described will improve resolution of when a release occurred, it will not improve the window of opportunity for treatment by reducing the time from release to reporting a positive result.
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From page 202... ...
Perhaps a unit like the BDS could be designed using basic off-the-shelf components (e.g., Cepheid GeneXpert or bioMérieux BioFire technology) for use in indoor settings such as train and subway stations, pedways, and airports.
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From page 203... ...
for an extensive review of collection, detection, and identification technologies, as well as issues of general consideration surrounding biological detection systems.) An advantage to having the BioWatch laboratory located within an established public health laboratory is that many of these facilities participate in the CDC's Advanced Molecular Detection initiative, and in doing so have acquired sophisticated equipment that can be shared with BioWatch for the identification of pathogens.
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From page 204... ...
In conclusion, I estimate that, by utilizing a cyclone collector and laboratory robotics for sample processing and PCR analysis, the time from sample receipt to results reporting could be halved. And, laboratory staff could also be reduced to a similar degree.
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From page 205... ...
2001. Biological Detec tion System Technologies, Technology and Industrial Base Study: A Primer on Biological Detection Technologies, Final Report.
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