ABSTRACT
The earth’s biosphere contains untold numbers and kinds of microorganisms. Humans have an interaction with microorganisms that is dynamic and modified by many factors. From the beginning of microbiology, with Van Leeuwenhoek’s application of the microscope, small ‘‘animalcules’’—microbes-were suspected of causing disease [1]. It was not until Koch published his classic paper on anthrax that these suspicions were proven, through rigorous experimentation as per Koch’s four postulates [2]. Although Koch’s postulates were for the determination of causation attributable to a single microbial species, the disease process is often more complex, involving multiple etiologies [3].
