Phenotypic characterization of Nocardia spp. isolated from Iran soil microflora

Aims: The present study was conducted to identify Nocardia spp. from Iran soil by various phenotypic tests. Materials and Methods: A total of 300 soil samples were collected of five different geographical regions in Iran. Nocardia isolation was performed by paraffin baiting technique. The colonies that were similar to be Nocardia spp. were stained with Gram, partially acid fast and acid-fast. Phenotypic tests were used for identification of Nocardia spp. Results: After analysis of phenotypic tests, the identified species are as follow: Nocardia asteroides (49.12%), Nocardia cyriacigeorgica (24.56%), Nocardia otitidiscaviarum (38.6%), N. asteroides complex (19.29%), Nocardia africana (3.5%), and Nocardia pseudobrasiliensis, Nocardia coubleae, Nocardia ignorata (each species; 1.75%). In this study, some of isolates (8.77%) remained undetected.Conclusion: Due to great number of Nocardia spp., high similarities among biochemical characteristics of species and the variability of some these characters, a wide range of biochemical tests should be used to identify Nocardia spp. to gain more accurate results.