Serological comparison of type strains of porcine, bovine, and ovine mycoplasmas with atypical colony morphology

The type strains of Mycoplasma hyopneumoniae, M. flocculare, M. dispar, and M. ovipneumoniae, all characterized by nipple-less colonies on solid media, were compared serologically. By indirect hemagglutination and by complement fixation tests they were found to constitute a related group. By crossed immunoelectrophoresis a sharing of common antigens was demonstrated, whereas no cross reactivity was noted by the metabolism inhibition test.The type strains of Mycoplasma hyorhinis and Mycoplasma bovirhinis were included in the study for comparison. Although some cross reaction was noted, they appeared just moderately related to the nipple-less group as well as to each other.