Resumo

Introduction: Candida parapsilosis has emerged as an important cause of invasive fungal infections, especially in neonates and immunocompromised patients, and has been associated with cases of fungemia in several parts of world in recent year. Nowadays, phenotypically indistinguishable, C. parapsilosis is a complex composed of three genetically distinct groups, C. parapsilosis sensu stricto, C. orthopsilosis and, C. metapsilosis. Materials and Methods: A hundred isolates of C. parapsilosis sensu lato from the yeast stock collection of the Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil; and three reference ATCC strains, were analyzed in this study. These included isolates from blood cultures and catheter tips from hospitalized patients admitted into three different health units (HSE, HUPE and SAM) in Rio de Janeiro, between 1998 and 2006. The phenotypic methods API 20 C AUX and Vitek 2 system were used for confirmation of species; DNA sequencing of the D1/D2 region of the 28S rDNA gene, PCR with primers species-specific and PCR-RFLP (double digested with Sau96I and HhaI) of the ITS region were the methodologies applied to molecular identification. Results and Discussion: The majority of the isolates derived from HSE (76%) while 20% derived from HUPE and only 4% from SAM. Isolates included 83 from blood cultures and 17 from catheter tips. Sequencing, when compared with available sequences from GenBank, showed that 61 isolates were C. parapsilosis sensu stricto, 37 belong to C. orthopsilosis, and confirmed that the remaining two isolates were C. metapsilosis. Two isolates that the sequencing proved be C. parapsilosis sensu stricto, the PCR species-specific and PCR-RFLP of the ITS region showed be C. orthopsilosis, thus the concordance between the methods was 98%. DNA molecule has been the main target when it is necessary the correct identification, the sequence is unique in each individual and can be exploited to correlations and genetic studies. Conclusion: C. metapsilosis, C. orthopsilosis, and C. parapsilosis sensu stricto are still not identified by routine biochemical laboratory tests, but with the aid of DNA-based techniques, including PCR species-specific and PCR-RFLP, these can be identified, allowing an epidemiological assessment and correct identification of the isolates.