The Complexity of Nocardia Taxonomy: Implications for the Clinical Microbiology Laboratory

The use of gene sequencing has dramatically increased the number of recognized species of Nocardia, many of which have been described as human pathogens. Molecular techniques have also demonstrated differences among isolates previously considered to belong to the same species. These changes have made it difficult for clinical laboratories to identify isolates accurately to the species level and for clinicians and researchers to correlate current species designations with reports in the older literature. We present here an overview of current Nocardia taxonomy and information on current identification and reporting techniques.