Nocardia africana sp nov., a new pathogen isolated from patients with pulmonary infections

Eight actinomycete strains, isolated from 8 out of 400 sputum samples exami ned, taken from patients with pulmonary diseases at the Chest Unit of Khart oum Teaching Hospital in the Sudan, were provisionally assigned to the genu s Nocardia according to morphological criteria. These isolates were studied further in order to establish their taxonomic status. They were found to h ave morphological and chemical properties typical of nocardiae and formed a monophyletic clade in the 16S ribosomal DNA tree together with Nocardia va ccinii. The strains showed a unique pattern of phenotypic properties that d istinguished them from representatives of recognized Nocardia species, incl uding Nocardia vaccinii. The strains were considered to merit species statu s and were designated Nocardia africana sp. nov. The findings of the presen t study are consistent with the view that pulmonary nocardiosis may occur i n a substantial proportion of patients who exhibit chronic lung diseases in African countries. It is important, therefore, that clinicians in such cou ntries consider this condition, especially when patients with respiratory i nfections fail to respond to antitubercular therapy.