Molecular identification of non-Cryptococcus yeasts associated with pigeon droppings in Shiraz, Southern Iran

Birds are considered as a reservoir for pathogenic and non-pathogenic fungi. Pigeon droppings have the potential for spreading these fungi to the environment. Cryptococcus species are important fungi associated with pigeon droppings. In this regard, there are many types of yeast associated with guano that is important for human and animal health.

The main objective of this study is the identification of non-Cryptococcus yeasts isolated from pigeon dropping in Shiraz, Southern Iran.

A total of 100 unknown yeasts, which were previously screened and identified as non-Cryptococcus from pigeon guano through the conventional methods, were used in this study. Identification of the isolates was performed based on conventional methods and DNA sequence analysis of internal transcribed spacer (ITS) rDNA gene region. The sequence results were deposited in NCBI database using the Basic Local Alignment Search Tool (BLAST).

A total of 16 species belonging to 7 genera were identified as Candida spp. 51% (8 species), Rhodotorula sp. 24%, Trichosporon spp. 21% (3 species), Rhodosporidium 2%, Saccharomyces 1%, Rhizoctonia 1%, and Meyerozyma 1%. The predominant isolates were Rhodotorula rubra (24%), Candida famata (20%), and Trichosporon asahii (13%). The other species were Rhodosporidium kratochvilovae 2 (2%), Saccharomyces cerevisiae 1 (1%), Rhizoctonia solani 1 (1%), and Meyerozyma caribbica 1 (1%).

Pigeon excreta examined in this study were associated with several kinds of opportunistic yeasts which could cause diseases in prone human and animals.