AUTHOR=Schneider José , Mateo Estibaliz , Marcos-Arias Cristina , Eiró Noemi , Vizoso Francisco , Pérez-Fernández Román , Eraso Elena , Quindós Guillermo 

TITLE=Antifungal Activity of the Human Uterine Cervical Stem Cells Conditioned Medium (hUCESC-CM) Against Candida albicans and Other Medically Relevant Species of Candida

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02818

DOI=10.3389/fmicb.2018.02818

ISSN=1664-302X

ABSTRACT=<p><bold>Background:</bold> Candidiasis is a major cause of human morbidity and mortality. Human uterine cervical stem cells conditioned medium (hUCESC-CM) is obtained from stromal stem cells of the cervical transformation zone, which are in permanent contact with a wide array of potential vaginal pathogens. In previous reports we have found that hUCESC-CM has antitumor and antibacterial potential. Since <italic>Candida</italic> is the most prevalent yeast in the human vagina, it seems plausible that hUCESC-CM might also show activity against it.</p><p><bold>Methods:</bold> In a preliminary step, to evaluate if hUCESC-CM showed any activity at all on <italic>Candida</italic> growth, <italic>in vitro</italic> activities of hUCESC-CM against fluconazole-susceptible reference strains of <italic>Candida albicans, Candida glabrata, Candida krusei</italic>, and <italic>Candida parapsilosis</italic> were studied with a microdilution method on RPMI 1640, using the BioScreen C microbiological incubator. Each measurement was repeated five times. The same methodology was used subsequently on fluconazole-susceptible and fluconazole-resistant <italic>Candida</italic> isolates from blood and vagina of those species corresponding to the reference strains of <italic>Candida</italic> against which activity had been detected in the previous study. Moreover, two fluconazole-resistant clinical isolates of <italic>Candida auris</italic> from blood and urine were also included.</p><p><bold>Findings:</bold><italic>In vitro</italic> inhibitory activity of hUCESC-CM ranged from 57.5 to 96.6% growth-reduction against fluconazole-susceptible reference strains of <italic>Candida albicans, Candida glabrata</italic>, and <italic>Candida parapsilosis</italic>. hUCESC-CM also reduced the growth of all fluconazole-susceptible tested vaginal isolates by more than 50%. For fluconazole-resistant isolates, growth-reduction was higher than 67% for <italic>Candida albicans</italic>, regardless of its origin (vagina or blood). The isolate of <italic>Candida auris</italic> from urine with a MIC &gt; 128 μ/ml for fluconazole was also significantly inhibited. However, hUCESC-CM was almost inactive against any of the fluconazole-resistant blood isolates of <italic>Candida glabrata, Candida parapsilosis</italic>, and <italic>Candida auris</italic> tested.</p><p><bold>Interpretation:</bold> This is the first report about the growth-inhibiting properties of conditioned medium from human stromal stem cells against different species of <italic>Candida</italic>. Antifungal activity of stromal stem cells depends on their site of origin, being most effective against <italic>Candida</italic> species most prevalent at that particular location. If confirmed in further studies, these findings might result in a completely new therapeutic approach against superficial and invasive candidiasis.</p>