What is Nocardiosis?

Nocardiosis (synonyms: streptotrichosis, cladotrichosis, atypical actinomycosis; Nocardiose – German; nocardiose – French) – mycosis, characterized by a long progressive course with frequent damage to the lungs, central nervous system. Lethal outcomes are frequent.

Causes of Nocardiosis

Infections due to Nocardia spp. happen both in humans and in animals. Differences in etiology, clinical symptoms, treatment and prognosis allow us to distinguish two subgroups of diseases, namely sensu stricto nocardiosis and actinomycetes. The latter, which may also be called “actinomycotic mycetomas,” are a clinically well-defined nosological form of the disease with a heterogeneous etiology that causes not only Nocardia, but also Actinomadura and Streptomyces spp.

The definition of nocardiosis, although, first of all, etiological, is at the same time both clinical and pathological. Its potential causative agents are Nocardia asteroides, Nocardia farcinica, Nocardia nova, Nocardia brasiliensis, Nocardia pseudobrasiliensis, Nocardia otitidiscaviarum and Nocardia transvalensis. Significant doubts remain regarding the taxonomic status of N. asteroides, N. farcinica, and N. nova, which affects their identification. Until recently, all of these microorganisms were included in N. asteroides, but were then separated from N. asteroides sensu stricto by taxonomic and molecular methods. Thus, it is still difficult to assess the extent to which N. farcinica and N. nova are involved in human infections, although at least the latter can be reliably identified.