Conversion of Pleuropneumonialike Organisms to Bacteria.

Abstract
A high frequency of appearance of diphtheroids in liquid cultures of 3 established strains of PPLO, campo "L", V73, and SF29, was noted. Statistical, morphological, biochemical and sero-logical tests show that a relationship exists between these diphtheroids and the PPLO in which cultures the bacteria appear. Statistical tests suggested that the diphtheroids were not contaminants. Biochemical tests showed that diphtheroids from the oral cavity and from the air differed from diphtheroids appearing in cultures of PPLO. Cross agglutination reactions between PPLO strains giving rise to diphtheroids and the derived diphtheroids were demonstrated. Although PPLO strains not giving rise to diphtheroids did not cross-react with the diphtheroids, all the PPLO strains tested were serologically related.