Nocardia, Rhodococcus, Gordonia, Actinomadura, Streptomyces, and Other Aerobic Actinomycetes

Abstract

Abstract The anaerobic organisms now in the genus Actinomyces and the aerobic organisms grouped together as the “aerobic actinomycetes” were previously presumed to be related to one another on the basis of shared features of microscopic and colonial morphology. The microscopic and colonial morphologies of organisms in the genus Actinomadura , which contains more than 100 validly named species or subspecies, are very similar to those in the genus Streptomyces . Species in the genus Saccharopolyspora were initially thought to be related to Nocardia and Streptomyces by biochemical characteristics but are phylogenetically distinct from those genera. However, an unknown number of Gordonia infections may be missed, either because the isolate is considered an insignificant coryneform Gram‐positive rod or because the isolate is misidentified by biochemical methods as belonging to another genus, such as Nocardia or Rhodococcus .