Identification of Candida species from fecal samples of pigeons in Riyadh, Saudi Arabia

Domestic pigeons (Columba livia domestica) are potential reservoirs of opportunistic yeasts that may pose health risks to humans, particularly in urban environments. This study aimed to investigate the prevalence, seasonal distribution, and molecular identification of Candida species in pigeon feces across Riyadh, Saudi Arabia. Fecal samples were collected from 64 pigeons across four regions of Riyadh during all four seasons. Yeasts were isolated using selective Sabouraud dextrose agar and CHROMagar Candida, purified, and preserved. Species-level identification was performed via morphological analysis, MALDI-TOF mass spectrometry (MS), and molecular techniques targeting the ITS1-5.8S-ITS2 region. Phylogenetic analysis was conducted on confirmed Candida albicans isolates. Overall, 20.31% (n=13) of the samples were positive for fungal isolation. The predominant species were C. albicans, Pichia kudriavzevii, and Clavispora lusitaniae. Seasonal analysis revealed the highest prevalence in spring (7.81%), while the central region of Riyadh showed the highest regional prevalence (7.81%). MALDI-TOF MS successfully identified C. lusitaniae and P. kudriavzevii, whereas C. albicans was confirmed via PCR and ITS sequencing (GenBank: OR467467 and OR467468). Phylogenetic analysis placed C. albicans isolates in a well-supported monophyletic clade. Environmental factors such as temperature and humidity influenced fungal prevalence. Cryptococcus neoformans was not detected. Domestic pigeons in Riyadh serve as environmental reservoirs of pathogenic Candida species, highlighting potential public health risks, particularly for immunocompromised individuals. These findings emphasize the need for monitoring urban bird populations to mitigate opportunistic fungal transmission.