HETEROGENEITY AMONG NOCARDIA ASTEROIDES STRAINS

Abstract

DNA hybridizations, base composition determinations, and tests for physiological reactions were performed on 10 isolates of Nocardia asteroids differing in microscopic colonial morphology, carbon compound utilization, and virulence for mice. One strain was eliminated from the species by all three methods and identified as N. otitidis-cavarium (N. caviae). Relatedness among the remaining 9 isolates, expressed as relative percentage binding at two temperatures, fell into two groups. The range of base composition of the DNA from these isolates was 67.7 to 69.2% GC. Formal subdivision of the taxon based on variations in physiological reactions and DNA homologies was judged to be premature.