An Approach to the Taxonomy of Gram-positive Anaerobic Cocci. 4. The Cell Wall Composition

Abstract

The classification of Gram-positive anaerobic cocci (GPAC) has always been very unsatisfactory. Attempts to clarify the taxonomy of GPAC have involved several methods including the analysis of the composition of bacterial cell wall. In an attempt to obtain information on the cell walls of 24 strains of GPAC isolated from clinical materials at St. Lukes, Guilford, and St. Thomas Hospital, London, the amino acid and amino sugar composition was quantitatively determined by an amino acid analyzer, using the method of Park and Hancock. The present study has revealed that the evaluation of the cell wall components is an accurate and reproducible method for classification of GPAC. The investigation showed that there are major differences in the amino acid composition of the cell walls of the members of GPAC. On balance, the separation of most GPAC using this system in general is consistent with the principles of Holdman et al (1977) and added valid characteristics for certain organisms such as differentiation of the species of Pst. micros from Pc. magnus, and recognition of the species of Pc. variablis and Pc. anaerobius as a variant species of Pc. magnus. The most unexpected finding was the designated reference strains of Pc. asaccharolytius varied significantly in their cell wall components. Therefore, additional strains must be studied in order to clarify the characterization and hence the nomenclature of such organisms.