Presumptive diagnosis of pulmonary nocardiosis: value of sputum microscopy.

Three hundred samples of sputum from patients suffering from various forms of pulmonary disorders were homogenized by pancreatic digestion, examined microscopically and cultured on brain heart infusion agar, trypticase soy agar, in brain heart infusion broth, trypticase soy broth and McClung's carbon-free broth. Several elements of varying morphological forms, believed to be from aerobic actinomycetes or nocardias, were observed in 16 cases. Six strains of Nocardia asteroides, one N. brasiliensis, eight of Rhodococcus species and one Micromonospora were isolated and studied at various stages of growth. Several nocardial and rhodococcal elements closely resembling those observed in the Gram-stained sputa were found. It is suggested that some of those in the sputum were from nocardias and that their appearance in sputum, as seen from the Gram-stained slide, when combined with clinical symptoms can serve for a presumptive diagnosis of pulmonary nocardiosis pending a more definitive identification by a specialized laboratory.