Identification and molecular analysis of yeasts found in domestic pigeon droppings in Montes Claros, MG, Brazil

Abstract

Pigeon droppings carry microorganisms such as Candida spp., which have high genetic variability and are the most common opportunistic pathogens in humans. There is a need to establish fast, reliable and simple laboratory methods to differentiate pathogenic from non-pathogenic yeast species in pigeon droppings, as they can be a source of contamination for humans. We examined yeasts isolated from domestic pigeon droppings through a proteomic approach using matrix-assisted laser desorption ionization (MALDI-TOF). We also examined genetic characteristics of the isolates by restriction fragment length polymorphism (RFLP) PCR and enterobacterial repetitive intergenic consensus sequences PCR methods. Five colonies isolated from domestic pigeon droppings collected at three different sampling locations on the roof of a Brazilian university building were identified as Candida krusei and Candida rugosa by MALDI-TOF. Phylogenetic studies using the two PCR-based molecular methods were able to differentiate the species C. krusei and C. rugosa into different groups. These genomic methods gave similar results and proved useful for genetic diversity analysis and interspecific differentiation of Candida isolates.