ABSTRACT
Bacteria are usually classified according to the Linnean binomial scheme of genus and species, although many kinds of systematic compilations are possible. Detailed classification of bacteria utilizes results of cytological, biochemical, and physiological tests as well as specialized techniques of strain identification (such as serotyping, bio-typing, bacteriophage typing, and genetic analyses including measurement of guanine and cytosine (GC) contents and DNA-DNA homology analysis). The most widely used system of classification and nomenclature in the United States is Bergey's Manual of Determinative Bacteriology. Bacteria form a heterogeneous group of procaryotic cells anatomically, physiologically, and biochemically. The procaryotic bacteria shows considerably narrow range of structural and biochemical variations as compared to the eucaryotic cells. Thus, evolutionary specialization among bacteria is expressed in metabolic rather than structural terms. The cytological recognition of procaryotic organization supported by biochemical and physiological data provided the foundation for a coherent, systematic view of the nature of bacteria such as that described in Bergey's Manual of Determinative Bacteriology.
