CASE CLOSED … what really happened in the 2001 anthrax attacks?

* Post Amerithrax: Advancing the Science and Engineering of Decontamination

Posted by DXer on October 31, 2012



2 Responses to “* Post Amerithrax: Advancing the Science and Engineering of Decontamination”

  1. DXer said

    J Appl Microbiol. 2014 Sep 8. doi: 10.1111/jam.12644. [Epub ahead of print]
    The impact of inducing germination of Bacillus anthracis and Bacillus thuringiensis spores on potential secondary decontamination strategies.
    Omotade TO1, Bernhards RC, Klimko CP, Matthews ME, Hill AJ, Hunter MS, Webster WM, Bozue JA, Welkos SL, Cote CK.
    Author information

    • 1United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Bacteriology Division, 1425 Porter Street, Fort Detrick, 21702-5011, Frederick, MD, USA.
    Decontamination and remediation of a site contaminated by the accidental or intentional release of fully virulent Bacillus anthracis spores is difficult, costly, and potentially damaging to the environment. Development of novel decontamination strategies that have minimal environmental impacts remains a high priority. Although ungerminated spores are amongst the most resilient organisms known, once exposed to germinants, the germinating spores, in some cases, become susceptible to antimicrobial environments. We evaluated the concept that once germinated, B. anthracis spores would be less hazardous and significantly easier to remediate than ungerminated dormant spores.
    Through in vitro germination and sensitivity assays, we demonstrated that upon germination, B. anthracis Ames spores and Bacillus thuringiensis Al Hakam spores (serving as a surrogate for B.anthracis) become susceptible to environmental stressors. The majority of these germinated B. anthracis and B. thuringiensis spores were non-viable after exposure to a defined minimal germination-inducing solution for prolonged periods of time. Additionally, we examined the impact of potential secondary disinfectant strategies including bleach, hydrogen peroxide, formaldehyde, and artificial UV-A, UV-B and UV-C radiation, employed after a 60 min germination-induction step. Each secondary disinfectant employs a unique mechanism of killing; as a result germination-induction strategies are better suited for some secondary disinfectants than others.
    These results provide evidence that the deployment of an optimal combination strategy of germination induction/secondary disinfection may be a promising aspect of wide-area decontamination following a B. anthracis contamination event.
    By inducing spores to germinate, our data confirm that the resulting cells exhibit sensitivities that can be leveraged when paired with certain decontamination measures. This increased susceptibility could be exploited to devise more efficient and safe decontamination measures and may obviate the need for more stringent methods that are currently in place. This article is protected by copyright. All rights reserved.

    Author Information
    • United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Bacteriology Division, Frederick, MD, USA

  2. DXer said

    The FDA Staff also has been busy.

    I’m not a scientist. But why isn’t the headline today that the added benefit was not statistically significant.

    I thought the take-home of the couple of statistics courses I took was to prompt me to be skeptical of such reports absent a finding of statistical significance.

    Anthrax Drug Effective, FDA Staff Finds

    By David Pittman, Washington Correspondent, MedPage Today
    Published: October 31, 2012

    The FDA seemed to tentatively support the benefits of the investigational monoclonal antibody raxibacumab for treating inhalational anthrax following new animal studies, documents released before a Friday advisory committee meeting showed.

    Rabbits that received the antibiotic levofloxacin (Levaquin) in combination with raxibacumab tended to show a greater survival rate (about 17%, P=0.0874) compared with those treated with levofloxacin alone, the FDA said Wednesday.

    “Although a positive, statistically significant added benefit result was not achieved with this underpowered study design, there appears to be a trend towards greater survival in rabbits when raxibacumab is coadministered with levofloxacin 84 hours after inhalational anthrax exposure,” FDA reviewers wrote in briefing documents released ahead of Friday’s Anti-Infective Drugs Advisory Committee meeting, at which committee members will vote on raxibacumab’s safety and efficacy.

    Because of the rare nature of anthrax, it is extremely difficult, if not impossible, to conduct clinical trials in humans. Instead, raxibacumab’s manufacturer, GlaxoSmithKline subsidiary Human Genome Sciences, conducted efficacy trials in animals and safety studies in normal, human volunteers and submitted its application to the FDA under the agency’s “animal rule.”

    Human Genome Sciences originally sought FDA approval for raxibacumab in 2009, but the agency denied approval at the time, expressing doubt over the drug’s added benefit. There was no difference in survival rates between levofloxacin and raxibacumab/levofloxacin study groups when the drugs were administered immediately after detection of the anthrax in animals.

    To address this concern, researchers administered the drugs 84 hours after exposure to anthrax. While only 76 of the 180 rabbits (42%) survived till the 84-hour mark, 82% in the study arm survived 28 days, compared with 65% with levofloxacin alone.

    Additional treatments for anthrax could prove useful, the FDA said, citing a fall 2001 terrorist attack where letters containing anthrax spores were mailed to news media offices and two U.S. senators, killing five people.

    After that attack, the CDC recommended the use of two or three antimicrobials in combination, and anthrax currently is treated with penicillin G and tetracycline-class drugs.

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