Candida parapsilosis is a complex made up of three species (Candida parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis) which differ genetically. Of the three, sensu stricto has emerged over the past 10 years as an important hospital pathogen, and is currently the second most frequent yeast isolate in candidemias, after C. albicans, in addition to being considered the most pathogenic and prevalent in different human niches, both under immunocompetent and immunocompromised conditions. In Argentina and worldwide, no data is available on the distribution and behavior of the complex in oral cavity niches, and there is little information on its epidemiology. Aim: to characterize Argentine isolates of different species in the C. parapsilosis complex from different oral cavity sites and other ecological niches. Methodology: retrospective, cross-sectional, descriptive study on a collection of isolates which were previously identified by conventional methods as parapsilosis complex, in order to distinguish the species by using end-point PCR with specific primers derived from a single sequence in the ITS1-5.8SrRNA-ITS2 region. Results: 95% of the isolates were identified as Cp. sensu stricto, which was recovered with higher probability from oral mucosa sites, under pathological conditions, and in presence of intraoral appliances. Seventy-four percent of the strains were recovered under conditions of immunocompetence. Hundred percent had resistant phenotype to flucytosine. Conclusions: Cp. sensu stricto is a common species in different ecological niches in the Argentine population. It is more likely to be recovered under conditions of immunocompetence. Dysbiosis of the mouth favors the growth of Cp. sensu stricto, which under these conditions may become a source for cross-transmission of more or less virulent strains by direct person-to-person contact, and a potential source of candidemia or invasive infections through hematogenous dissemination of strains with increased pathogenicity.
