Efficacy and durability of Bacillus anthracis bacteriophages used against spores. (Practical Stuff!).* Anthrax anthrax (ăn`thrăks), acute infectious disease of animals that can be secondarily transmitted to humans. It is caused by a bacterium (Bacillus anthracis is caused by B. anthracis, a Gram-positive, rod-shaped, spore-forming bacterium. * Current medical strategies may fail against B. anthracis strains that are resistant to antibiotics or have not been targeted by vaccines. * Also, antibiotics and vaccinations are more effective against lower initial concentrations of bacteria. * To augment current strategies, new treatments should lower the initial amount of bacteria (the inoculum inoculum /in·oc·u·lum/ (-ok´u-lum) pl. inoc´ula material used in inoculation. in·oc·u·lum n. pl. dose) by -- attacking bacteria as spores germinate and -- targeting a wider variety of anthrax strains. * Long-lasting anthrax spores can be killed only by relatively harsh methods. * The spores are not metabolically active and must be physically disabled rather than poisoned. * Gamma irradiation, ultraviolet light Ultraviolet light A portion of the light spectrum not visible to the eye. Two bands of the UV spectrum, UVA and UVB, are used to treat psoriasis and other skin diseases. , high-pressure steam, nanoscale powder biocides, and various gases can kill spores. * None of these approaches, however, is safe for use where humans are present. * Naturally occurring viruses of bacteria may help augment antianthrax strategies. * These viruses are called bacteriophages, or phages. * The phages must be durable and effective under a variety of conditions. * They also must maintain their bacteria-killing ability in the presence of various body fluids and cells. * Potentially useful phages are abundant wherever bacteria are naturally found, as in soil. * Spraying is a method very likely to be used for skin applications of phage-based decontamination decontamination /de·con·tam·i·na·tion/ (de?kon-tam-i-na´shun) the freeing of a person or object of some contaminating substance, e.g., war gas, radioactive material, etc. de·con·tam·i·na·tion n. techniques. * In this study, phages were sprayed onto dried spores. * This technique was found to inhibit bacterial growth Bacterial growth The processes of both the increase in number and the increase in mass of bacteria. Growth has three distinct aspects: biomass production, cell production, and cell survival. in a basic dose-response pattern. * The research also studied phage phage: see bacteriophage. phage - A program that modifies other programs or databases in unauthorised ways; especially one that propagates a virus or Trojan horse. See also worm, mockingbird. The analogy, of course, is with phage viruses in biology. durability under conditions that might be expected during manufacturing, storage, or use of phages. * Temperatures of 55[degrees]C or higher reduced or eliminated phage infectivity * Desiccation des·ic·ca·tion n. The process of being desiccated. des  ic·ca also eliminated infectivity.
* Phages survived filtration, aerosolization, and treatments with blood and perspiration. * UV light reduced phage infectivity by about four orders of magnitude over 30 minutes. * Under similar conditions, however, target spores were nearly completely inactivated inactivated rendered inactive; the activity is destroyed. inactivated viruses treated so that they are no longer able to produce evidence of growth or damaging effect on tissue. within two minutes. * Thus, phage susceptibility to limited UV light may not compromise bacteria-killing ability. |
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