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AbstractChemical, biological, radiological, nuclear and explosive (CBRNE) response teams are responsible for mitigating and investigating events such as the distribution of anthrax letters throughout the US Postal Service in 2001. One consideration will be the examination of contaminated physical evidence to identify those responsible. Decontamination agents are often used to inactivate or neutralize chemical and/or biological warfare agents so that once-contaminated objects can be handled safely. The objective of this project was to determine the impact of different decontamination agents on physical evidence including DNA, documents, fingermark and footwear evidence. In Phase 1, vaporous hydrogen peroxide (VHP), gamma irradiation, dry fogging, chlorine dioxide, MODEC MDF-500, Bioxy-S, ozone and formaldehyde were tested. Promising decontamination agents were selected for Phase 2 when physical evidence was exposed to Bacillus thuringiensis(Bt), an anthrax surrogate, prior to decontamination. VHP, gamma irradiation, dry fogging, formaldehyde and chlorine dioxide were tested in Phase 2. Results indicate that several forensic analyses were impacted. VHP and gamma irradiation were used across different laboratories with inconsistent results observed for some forensic protocols. Further investigation indicated that these results could be explained by variation in contamination protocols between laboratories.Les équipes d'intervention chimique, biologique, radiologique, nucléaire et explosive (CBRNE) sont chargées d'atténuer et d'enquêter sur des événements tels que la distribution de lettres d'anthrax dans l'ensemble du service postal américain en 2001. Une considération sera l'examen des preuves physiques contaminées pour identifier les responsables. Les agents de décontamination sont souvent utilisés pour inactiver ou neutraliser les agents de guerre chimiques et/ou biologiques afin que des objets autrefois contaminés puissent être manipulés en toute sécurité. L'objectif de ce projet était de déterminer l'impact de différents agents de décontamination sur les preuves physiques, y compris l'ADN, les documents, les traces de doigt et les chaussures. En phase 1, le peroxyde d'hydrogène vaporeux (VHP), l'irradiation gamma, la brumisation sèche, le dioxyde de chlore, le MODEC MDF-500, le Bioxy-S, l'ozone et le formaldéhyde ont été testés. Des agents de décontamination prometteurs ont été sélectionnés pour la phase 2 lorsque des preuves physiques ont été exposées à Bacillus thuringiensis (Bt), un substitut de l'anthrax, avant la décontamination. Le VHP, l'irradiation gamma, la brumisation sèche, le formaldéhyde et le dioxyde de chlore ont été testés à la phase 2. Les résultats indiquent que plusieurs analyses médico-légales ont été touchées. VHP et l'irradiation gamma ont été utilisée dans différents laboratoires avec des résultats incohérents observés pour certains protocoles médico-légaux. Une enquête plus approfondie a indiqué que ces résultats pourraient s'expliquer par la variation des protocoles de contamination entre les laboratoires.

ABSTRACTWe examined the utility of a single matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry method for the identification of security-sensitive biological agents (risk group 3 bacterial pathogens). The goal was 2-fold: to verify a method for inclusion into our scope of accreditation, and to assess the biological safety of extractions. We developed our sample flow to include a tube-based chemical extraction, followed by filtration, before processing on MALDI-TOF MS instruments in a containment level 2 laboratory.

ABSTRACTAntibodies against the protective antigen (PA) component of anthrax toxin play an important role in protection against disease caused by Bacillus anthracis. In this study, we examined defined combinations of PA-specific monoclonal antibodies for their ability to neutralize anthrax toxin in cell culture assays. We observed additive, synergistic, and antagonistic effects of the antibodies depending on the specific antibody combination examined and the specific assay used. Synergistic toxin-neutralizing antibody interactions were examined in more detail. We found that one mechanism that can lead to antibody synergy is the bridging of PA monomers by one antibody, with resultant bivalent binding of the second antibody. These results may aid in optimal design of new vaccines and antibody therapies against anthrax.

Neutralizing antibody responses to the surface glycoproteins of enveloped viruses play an important role in immunity. Many of these glycoproteins, including the severe acute respiratory syndrome-coronavirus (SARS-CoV) spike (S) protein form trimeric units in the membrane of the native virion. There is substantial experimental and pre-clinical evidence showing that the S protein is a promising lead for vaccines and therapeutics. Previously we generated a panel of monoclonal antibodies (mAbs) to whole inactivated SARS-CoV which neutralize the virus in vitro. 1,2 Here, we define their specificity and affinity, map several of their epitopes and lastly characterise chimeric versions of them. Our data show that the neutralizing mAbs bind to the angiotensin-converting enzyme 2 (ACE2) receptor-binding domain (RBD) of the SARS S protein. Three of the chimeric mAbs retain their binding specificity while one conformational mAb, F26G19, lost its ability to bind the S protein despite high level expression. The affinity for recombinant S is maintained in all of the functional chimeric versions of the parental mAbs. Both parental mAb F26G18 and the chimeric version neutralize the TOR2 strain of SARS-CoV with essentially identical titres (2.07 and 2.47 nM, respectively). Lastly, a comparison with other neutralizing mAbs to SARS-CoV clearly shows that the dominance of a 33 amino acid residue loop of the SARS-CoV RBD is independent of repertoire, species, quaternary structure, and importantly, the technology used to derive the mAbs. In cases like this, the dominance of a compact RBD antigenic domain and the central role of the S protein in pathogenesis may inherently create immunoselection pressure on viruses to evolve more complex evasion strategies or die out of a host species. The apparent simplicity of the mechanism of SARS-CoV neutralization is in stark contrast to the complexity shown by other enveloped viruses.

The Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV combination test received emergency use authorization approval by the United States Food and Drug Administration in December 2020, and Health Canada approval in January 2021. The performance characteristics of the GeneXpert Xpert Xpress SARS-CoV-2/Flu/RSV combination test were assessed at Lakeridge Health Oshawa and the National Microbiology Laboratory of Canada. The combination test was compared to the Xpert SARS-CoV-2 and Xpert Flu/RSV assays, and the BioFire FilmArray Respiratory Panel 2.1 (RP2.1) test kit. Materials evaluated were serial dilutions of chemically-inactivated SARS-CoV-2 and remnant clinical specimens (nasal or nasopharyngeal swabs) collected from patients. The limit of detection (LOD) for the SARS-CoV-2 component of the Xpert SARS-CoV-2/Flu/RSV combination test was determined to be <100 viral copies/mL when using chemically-inactivated SARS-CoV-2. In total, 86 clinical positive and 51 clinical negative samples were used for this study, with mixtures of clinical positives being used to mimic coinfection and screen for competitive inhibition. The combination test showed a high percent agreement with the Xpert SARS-CoV-2 and Xpert Flu/RSV tests, as well as the BioFire FilmArray RP2.1. Based on the findings from this study and a growing body of research, the Xpert SARS-CoV-2/Flu/RSV combination test will serve as an effective replacement for the Xpert SARS-CoV-2 and Xpert Flu/RSV assays.