Yeast Flora in Oropharyngeal and Rectal Mucous Membranes of Healthy and Critically Ill Neonatal Foals

Little is known about the normal or pathologic yeast flora in healthy and critically ill neonatal foals. The aims of this study were to evaluate the yeast flora colonizing the mucous membranes of the digestive tract (oropharynx and rectum mucous membranes) of healthy and hospitalized foals and to find out risk factors involved in yeast colonization of foals referred to a neonatal intensive care unit. A total of 240 swabs were collected from 21 healthy (group A) and 39 sick (group B) foals. In 14 of the 60 foals, yeast was isolated in at least one sample (23.3%): 3 of the 21 foals (14.3%) were positive in group A and 11 of 39 foals (28.2%) were positive in group B. The yeasts were isolated from rectal swabs obtained from none in healthy foals, whereas 5 of the 39 sick foals were positive; however, this difference was not statistically significant. No significant difference was also detected regarding oropharyngeal swabs between healthy (3/21) and sick (10/39) foals. The risk factors significantly associated with the isolation of yeasts from rectal swabs were female sex, treatment with oral antibiotics, and stressful diagnostic–therapeutic procedures. The only risk factor significantly associated with the isolation of yeast from oropharyngeal swabs was the treatment with antacids and gastroprotectants. The results show that fungi present in the gastrointestinal tract of neonatal foals were mainly environmental yeasts and suggested the absence of a stable fungal colonization. Candida was the genus frequently isolated in hospitalized foals, just as it is isolated in critically ill human neonates.