Background : Identification of Nocardia spp. in routine medical laboratories is based on phenotypic methods that is often time- consuming. The objective of this study was to diagnose Nocardia agents by PCR technique in BAL samples of patients with suspected tuberculosis admitted to hospitals in Tehran. Materials and Methods: In this study, 116 BAL samples of patients admitted in Baqiyatallah, Imam Khomeini and Shariati hospitals were collected within 8 months. Nocardia DNA was extracted by phenol-chloroform protocol. In Duplex PCR, primers NG1 and NG2 were used to amplify a Nocardia genus- specific 598-bp fragment of 16S rRNA gene. BetF and BetR primers were used as housekeeping gene to amplify 204-bp fragment. Gel-purified PCR products were sequenced. Results: Using Duplex PCR, 7 (%6.03) samples were positive for Nocardia spp. . Sequencing results showed that the species identified were N.cyriacigeorgica (6 case) and N. otitidiscaviarum (1 case). Conclusion: In the present study, DNA extracted from Nocardia Spp. in BAL specimens by manual method during minimum time which had not previous record in Iran. The study also was carried out on patients with suspected tuberculosis which restricted work has already been done on them. In this study, N. cyriacigeorgica was dominant species that has been introduced during recent years, which should be considered in clinical laboratories and research centers.

Keywords: Nocardia spp, PCR, Bronchoalveolar lavage (BAL)

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