Ricerc@Sapienza

Background: Candida albicans' ability to evade host immune responses represents a serious threat for vulnerable patients. Objectives: To investigate if (1) feces from healthy subjects exert anti-Candida activity; (2) fecal anti-Candida activity is modified by probiotic administration and (3) different probiotic differently modulate anti-Candida activity. Patients and methods: Feces from healthy donors were analyzed before and after seven days of dietary supplementation with two different probiotic formulations (VSL#3((R)); Vivomixx((R))). Candida albicans was cultured with decreasing concentrations of diluted feces, obtained before and after the treatment period. The relationship between anti-Candida activity of feces, interferon-alpha, anti-interferon-alpha antibodies and the expression of MxA, ISG15 and IFNAR1 was also evaluated. Results: Feces obtained prior to probiotic intake and feces collected after supplementation with VSL#3((R)) did not affect Candida albicans growth. On the contrary, a 3log(10) inhibition of Candida development was observed after Vivomixx((R)) intake. Interferon-alpha played a role in the inhibition of Candida growth. Conclusion: Fecal anti-Candida activity was not observed prior to probiotic supplementation. Seven days of administration of Vivomixx((R)) increased fecal anti-Candida activity, the same effect was not observed after intake of VSL#3((R)). The probiotic-induced anti-Candida activity seems to be related to an increased local production and release of interferon-alpha. Clinical trials are needed to determine if a short pretreatment with specific probiotic formulations may increase anti-Candida defenses in patients at risk.