Evaluation of exoenzyme activities, biofilm formation, and co-hemolytic effect in clinical isolates of Candida parapsilosis species complex

Candida parapsilosis species complex is considered as important emerging pathogens and little is known about their pathogenicity factors and co-hemolytic activity with different bacteria species. The aim of this study was to determine in vitro exoenzyme activities, biofilm formation, and co-hemolytic effect of different bacteria species on clinical C. parapsilosis complex isolates. In total, 67 C. parapsilosis complex isolates consist of C. parapsilosis sensu stricto 63/67 and Candida orthopsilosis 4/67 were used in this study. To determine the hemolytic activity of these species, Sabouraud dextrose sheep blood agar was used. Evaluation of the CAMP-like phenomenon carried out in the presence of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus agalactiae. Tube test method with ethylenediaminetetraacetic acid-rabbit plasma was used to determine coagulase activity, and biofilm formation was assessed by the tube method in assist of Sabouraud glucose broth (8%) medium. Fisher's exact tests were used for data statistical analysis. Sixty-six of 67 (98.5%) and 3/67 (4.5%) of the species showed hemolysin and coagulase activity, respectively. Fifty-five of 67 (82.1%) of species had ability for biofilm formation, and none of the samples exhibited co-hemolytic effect in the presence of four mentioned bacteria. No significant difference was found between the level of enzyme production and biofilm formation among the isolates.