Characterization of the gastrointestinal yeast microbiota of cockatiels (Nymphicus hollandicus): a potential hazard to human health.

Cockatiels are the world's second most popular psittacine pet bird, but no data characterizing their gastrointestinal microbiota have been found. Thus, the aim of this work was to characterize the yeast gastrointestinal microbiota of cockatiels and to evaluate the relevance of cockatiels as carriers of potentially pathogenic yeasts. A total of 60 cockatiels, from 15 different premises, were assessed. A thorough clinical examination was performed with each bird, and samples were collected from oral cavity, crop and cloaca. The stools were collected from cages where the birds were kept. The isolates were identified according to morphological and biochemical characteristics. Yeasts were isolated from at least one anatomical site of 65% of the birds and 64.3% of the stool samples. The oral cavity (53.3%) and the crop (58.3%) were the anatomical sites with the highest prevalence and the highest number of yeast isolates. Overall, 120 yeast isolates, belonging to 13 species, were obtained. The most frequently isolated species were Candida albicans, with 39 (32.5%) isolates, followed by Candida tropicalis (20%), Trichosporon asteroides (12.5%), Candida famata (10%) and others. Mixed yeast colonies were isolated from 23.3% of the birds and C. albicans was seldom found in association with other species (P<0.05). The results of this work demonstrated that cockatiels harbour potentially pathogenic yeasts throughout their gastrointestinal tract and in stools, and are prone to disseminating them in the environment.