Mycoplasma muris, a New Species from Laboratory Mice

Abstract

Three mycoplasma strains were isolated from the vaginal tracts of strain RIII mice. These isolates had similar biochemical and serological properties and grew on SP-4 medium but not on conventional mycoplasma medium containing horse serum and yeast extract. Anaerobic incubation was required. These organisms hydrolyzed arginine but not urea, produced a film and spot reaction, and were susceptible to 1.5% digitonin. Cholesterol was required for growth, and the organisms adsorbed to guinea pig erythrocytes and exhibited uridine phosphorylase activity. The organisms were serologically distinct from 82 Mycoplasma species and unclassified serotypes. On the basis of these findings and other morphological and biological properties of the organisms, we propose that mycoplasma strains with these characteristics belong to a new species, Mycoplasma muris. Strain RIII-4 (= ATCC 33757) is the type strain.