Indagine sulla presenza di lieviti nelle feci di puledro [Study on yeasts isolated from foal feces]

The aim of the present study was to identify yeasts in foal gastrointestinal tract. To our knowledge, there is currently no scientific data on this theme. Materials and Methods - 240 samples of droppings from 48 foals were examined. Samples were obtained at day 0, 2, 5, 8, 12 of life using sterile swabs. Each sample was dissolved in 2 ml of sterile water + 50 ml ml(-1) gentamicin and seeded onto Sabouraud dextrose agar supplemented with biphenyl 0.1%. The plates were incubated at 25 degrees C and examined at day 7 Every yeast isolate was checked for the presence of capsules by India ink testing. The isolates were also processed for germ tube production and examined for urease production. Their carbohydrate assimilation patterns were also defined using ID32 (bio/Merieux Italia, SPA, Roma). All the tests were carried out in duplicate. The final identification was based on the keys from da Kurtzman & Fell. Results - 14 foals (29,2%) were positive for yeasts. The prevalences of yeasts resulted: Candida colliculosa (1 foal), Candida da famata (3 foals), Cryptococcus laurentii (3 foals), Geotrichum sp. (5 foals), Rhodotorula sp. (3 foals) Saccharomyces cerevisiae (1 foal), Zygosaccharomyces sp. (1 foal). 3 different species of yeast were isolated from the same foal in 1 case. Yeasts were identified as: C. famata, Zygosaccharomyces sp. and Geotrichum. 2 different species of yeast were isolated from the same foal in 1 case. Yeasts were identified as: C. colliculosa and Rhodotorula sp. In 2 cases, the same yeast were isolated from two successive samples (Geotrichum sp. and Cr. laurentii). Discussion - The prevalence of isolation found in the present study (29,2%) seems to be significantly lower than in other species, as sheep (41%) and psittacines (49,2%). The age of the animals involved in the study (0-12 day of life) could be the causal factor: this, a previous investigation performed on the presence of yeasts in adult horse feces (Prevalence of yeasts in horse feces, Unpublished data), reported similar data as in foals. The isolation of the same specie of yeast from one foal in three or more successive samples were not carried out, suggesting a fail of fungal colonization of the gastrointestinal tract. Our results probably suggest a passive role of foals as carriers of yeasts. Our results suggest that the gastrointestinal tract of foals could have a role as a carrier to spread yeasts into the environment, in this case risk of fungi infections for the immunodepressed animals could be significantly high.