Viruses As Biocontrol Agents Of Microorganisms

Biocontrol is the application of organisms, or substances that organisms produce, to reduce or eliminate populations of unwanted species. Within the context of environments, this application is equivalent to the use of pesticides, with the unwanted organism serving as the pest. Within the context of medicine, this application is equivalent to that of, especially, the use of antimicrobial drugs. Typically, for any such agents, the application of greater amounts will result in a greater negative impact on target organisms, but levels of application will be limited by costs, convenience, or potential to cause harm to the environment or to the patient being treated. Biocontrol agents thus may be deemed superior, for example versus the use of synthetic pesticides or antimicrobials, should biocontrol agents supply some combination of greater efficacy potential, lower cost, greater convenience, or lower potential to cause various forms of harm. In terms of viruses as biocontrol agents, we can distinguish between whole viruses versus their products or derivatives. Potential targets can be further differentiated in terms of what can be described as the six kingdoms: Bacteria, Archaea, Fungi, Protista, Animalia, and Plantae. In this chapter we touch upon all of these kingdoms as possessing potential targets for virus-mediated biocontrol; nevertheless, consistent with the theme of this monograph, we focus particularly on the virus-mediated biocontrol of microorganisms. Given its substantial domination of the overall area of study, much of the review is derived from consideration of bacteriophage use against members of domain Bacteria. This is seen within the context of either phage-mediated biocontrol or instead the sub-category of such biocontrol known as phage therapy.