Molecular identification and phylogenetic analysis of Macrorhabdus ornithogaster based on the 18S rRNA gene in companion birds of Tehran, Iran.

Background: Macrorhabdus ornithogaster (MO) is an infectious yeast which can cause acute gastric disturbances in birds. It has a worldwide distribution with a broad host-range of bird species.

Aims: Molecular identification and phylogenetic analysis of MO based on the 18S rRNA gene in companion birds of Iran.

Methods: A total of 54 stool samples were taken from birds (10 species) suspected of being infected. The presence of MO in collected stool samples was investigated using direct wet mount microscopy. Specific primers were designed to identify the MO 18S rRNA gene by using PCR. PCR products were sequenced and phylogenetic analysis was performed to determine the molecular diversity.

Results: The obtained results demonstrated that 44.44% and 59.26% of the samples were diagnosed positive based on the first and second specific primers, respectively. MO was detected in the feces of canary, goldfinch, budgerigar, toucan, and English budge. Phylogenetic analysis revealed that MO sequence data from canaries, finches, and goldfinches had homology with an MO isolated from a German zebra finch. Moreover, MOs from cockatiels, rosy faced love birds, and budgerigars had a high phylogenetic similarity with multiple references, including American budgerigar, Japanese cockatiel, European goldfinch, and German budgerigar.

Conclusion: MO exists in many species of Iranian birds, including goldfinches, budgerigars, toucans, and English budgies. As indicated by phylogenetic and polymorphism data analysis, the newly designed specific primers spanning a large portion of 18S rRNA gene of MO, provides additional tool to detect and study the molecular diversity of MO.