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
| Origin | Strains | Candida parapsilosis complex |
|---|---|---|
| Human | CEMM 05-1-054 | C. parapsilosis sensu stricto |
| CEMM 01-1-165 | C. parapsilosis sensu stricto | |
| CEMM 05-5-083 | C. orthopsilosis | |
| CEMM 05-5-093 | C. orthopsilosis | |
| CEMM 05-5-087 | C. metapsilosis | |
| CEMM 05-5-086 | C. metapsilosis | |
| CEMM 01-1-167 | C. metapsilosis | |
| Veterinary | CEMM 03-2-045 | C. parapsilosis sensu stricto |
| CEMM 01-1-196 | C. parapsilosis sensu stricto | |
| CEMM 01-1-186 | C. parapsilosis sensu stricto | |
| CEMM 01-1-204 | C. parapsilosis sensu stricto | |
| CEMM 01-1-178 | C. orthopsilosis | |
| CEMM 01-1-200 | C. orthopsilosis | |
| CEMM 01-1-183 | C. orthopsilosis | |
| CEMM 01-1-190 | C. orthopsilosis | |
| CEMM 03-2-046 | C. metapsilosis | |
| CEMM 01-1-199 | C. metapsilosis | |
| Food | CEMM 01-1-169 | C. metapsilosis |
| Methods | Strains (n) | Chromogenic medium (n) | Phenotypical characteristics | Phenotypical identification (n) | n | Molecular identification (n) | Phenotypical identification agreement n (%) | |
|---|---|---|---|---|---|---|---|---|
| Microscopic analyses | ||||||||
| Chromogenic agar, Dalmau culture | 34 | White (17), pale pink (11) | Giant-cells, branched pseudo-hyphae and elongated blastoconidia | C. parapsilosis (28) | 28 | C. parapsilosis sensu stricto (16), C. orthopsilosis (8), C. metapsilosis (4) | 28/34 (82.3) | |
| Pale pink (6) | Wide elongated blastoconidia, with reduced filamentation | C. parapsilosis (6)b b Micromorphologically, presented cell arrangement weakly suggestive of C. parapsilosis complex, without typical features, such as giant-cells and branched pseudohyphae in a delicate tree-like pattern, presented unspecific molecular profile and were identified as C. guilliermondii through DNA sequencing. | 6 | - | ||||
| Biochemical profile a a Biochemical profile (+), (-) and (v) distinct from each presumptive identification of the Vitek 2™ system. The variable biochemical profile corresponds to the profile of the strain (-) or (+) or contradictory to the given test. Biochemical tests: LysA, l-lysine arylamidase; IMLTa, l-malate; ARG, arginine; ERYa, erythritol; GLYLa, glycerol; TyrA, tyrosine arylamidase; ARBa, arbutin; dGALa, d-galactose; GENa, gentiobiose; LACa, lactose; dCELa, d-cellobiose; GGT, gamma-glutamyl-transferase; dRAFa, d-raffinose; NAGA1, PNP-N-acetyl-BD-galactosaminidase 1; dMEla, d-melibiose; ISBEa, l-sorbose; IRHAa, l-rhamnose; XLTa, xylitol; SACa, saccharose/sucrose; AGLU, alpha-glucosidase; dTREa, d-trehalose; IARAa, l-arabinose; dGATa, d-galacturonate; dXYLa, d-xylose; ACEa, acetate; GRTas, glucuronate; NAGa, N-acetyl-glucosamine; dGNTa, d-gluconate. | ||||||||
| Chromogenic agar, Vitek 2 | 25 | White (3), pale pink (17) | (-) dRAFa, IMLTa, XLTa, ARBa, dCELa, ERYa, GENa, ISBEa; (v)IARAa, GRTas | (+) TyrA, dGNTa, dGATa; (v)GRTas | C. parapsilosis (20) (99%)c c Percentage of confidence in the identification by the Vitek 2™ system. | 20 | C. parapsilosis sensu stricto (17), C. orthopsilosis (2), C. metapsilosis(1) | 23/25 (92.0) |
| White (1), pale pink (3) | (-) TyrA, IMLTa, LACa, XLTa, ARBa, dCELa, ERYa, GGT; (v)dXYLa, dRAFa, dGATa, GENa, GRTas | (+) dRAFa, dGNTa, GENa, ISBEa, GRTas; (v)IMLTa, dGATa (LDO) | C. famata/C. parapsilosis (4) (LDO)d d Low discrimination organism. | 4 | C. parapsilosis sensu stricto (1), C. orthopsilosis (2) | |||
| Pale pink (1) | (-) LysA, TyrA, IRHAa, IMLTa, NAGA1, XLTa, ARBa, dCELa; (v) dXYLa, dRAFa, IARAa, dGNTa, dGATa, GLYLa, GENa, AGLU, GRTas | (+) dRAFa, NAGa, ARG, SACa, ACEa, dGALa, dGATa, GENa, ISBEa, GRTas; (v)GLYLa, IMLTa, IARAa, dGNTa | C. famata/C. parapsilosis C. tropicalis (1) (LDO)d d Low discrimination organism. | 1 | - | |||
