The intestinal mycobiota: a year of observation about the incidence of yeast's isolation in fecal samples

Background Yeast's presence, especially Candida's species, in the intestinal tract is now considered as part of the normal microbial human flora; however, fungal colonization of the colon may induce to fungal infections, becoming a risk not only in immunocompromised patients but also in normalcompetent subjects. The purpose of this epidemiological study was to evaluate the real incidence of yeasts into the fecal samples both from healthy outpatients and from inpatients, except those from wards concerning immunosuppressive and pediatrics pathologies. Methods Between September 2014 and October 2015, 685 stool's samples (383 from inpatients and 302 from outpatients) were subjected to culture test on Sabouraud Dextrose Agar and yeasts collected were identified by a semi-automated system Vitek2 (bioMerieux). Results Percentage of isolation was of 64% (N.=437) in the total fecal samples examined (59% in outpatients and 67% in inpatients) and the most frequently isolated was Candida albicans (63% N.=275) in both populations (60% in outpatients and 65% in inpatients). Conclusions These data testify the constant presence in the human gut of a fungal community that, according to us, could be defined as intestinal "mycobiota". This study wishes to be a contribution to discover the relationship established between human and yeasts and to evaluate the colonizing or pathogenetic role performed by these microorganisms.