Metabolic studies on three strains of Pleuropneumonia-like organisms isolated from man.

The peculiar type of growth common to Asterococcus mycoides (Pleuropneumonia bouum), pleuropneumonia-like organisms (PPLO), and L forms of bacteria has lead to confusion and controversy. This controversy involves the interrelationships of these groups and of strains within the groups as well as their relation to bacteria in general. Excellent reviews by Sabin (1941), Elleneberger-Nobel (1951), and Dienes and Weinberger (1951) summarize the various views of the subject. Most of the investigators in this field have used cytological, pathological, and serological techniques for obtaining their data. Except for work on Asterococcus mycoides (Pleuropneumonia bovum) (Holmes and Pirie, 1932) and L forms of rat and mouse origin (Warren, 1942), biochemical characterization for the large part has been confined to the measurement of activity in terms of pH changes in the growth media. With fast growing, actively metabolizing bacteria, pH change is a useful criterion. However, with relatively slow growing, metabolically sluggish pleuropneumonia-like organims, this measurement of gross activity may not be adequate since the activity may be too slight to produce a measurable change in pH. Moreover, the principal end products of metabolism may not be acid in nature. For these reasons, it was felt that an approach directed at determining specific metabolic activities would aid in further characterizing these organisms and perhaps clarify some of the existing confusion regarding them. Therefore, an initial study of the optimal conditions for growth and oxidative activity of one strain of these organisms for one substrate was undertaken. The substrate chosen was lactate since Somerson