Phenotype-driven strategies for screening Candida parapsilosis complex for molecular identification

Abstract

In this study, phenotypic methods presented >80% agreement with the molecular identification of 59 Candida parapsilosis complex. Growth at 15% NaCl or pH 7.0 significantly reduced cfu-counts of Candida orthopsilosis, suggesting these conditions may support the development of phenotypic methods for the differentiation of the cryptic species of C. parapsilosis complex.

Keywords: Candida parapsilosis; Salinity; pH conditions.

Fig. 1

Representative 2% agarose gel of Candida parapsilosis sensu lato, after specific PCR reactions. (A) Products obtained after the digestion of sadh gene – PCR fragments by the BanI restriction enzyme distinguishing the cryptic species: C. parapsilosis sensu stricto (lines 1, 4, 7); C metapsilosis (line 5); and C. orthopsilosis (lines 2, 3, 6); (B) the band patterns of 716 bp, obtained after sadh gene PCR reaction, suggestive of C. parapsilosis sensu lato (lines 11 and 12) and unspecific band patterns obtained for Candida guilliermondii (lines 8, 9, 10, 13, 14 and 15). Molecular marker: 1000 bp.

Fig. 2

Growth kinetics, expressed as cfu/mL of the cryptic species of the Candida parapsilosis complex after growth up to 72 h of culture in media with different salinity levels. (A) Sabouraud broth without NaCl (growth control); (B) Sabouraud broth with 5% NaCl; (C) Sabouraud broth with 10% NaCl; (D) Sabouraud broth with 15% NaCl. *Indicates statistically significant differences.

Fig. 3

Growth kinetics, expressed as cfu/mL, of the cryptic species of the Candida parapsilosis complex, after growth up to 72 h of culture in media at different pH levels. (A) Sabouraud broth pH 3.0; (B) Sabouraud broth pH 5.0; (C) Sabouraud broth pH 7.0. *Indicates statistically significant differences.