Identification of clinical saprochaete isolates at species level, comparison of antifungal susceptibility test results obtained with two different reference methods, and investigation of virulence factors

Saprochaete species are opportunistic pathogens that can cause fatal infections and nosocomial outbreaks, particularly in immunocompromised patients. Data on virulence factors are limited. In this study, it was aimed to confirm the species diagnosis of clinical Saprochaete isolates, to investigate the virulence factors by phenotypic methods and to investigate the susceptibility profiles with two different reference antifungal susceptibility test.57 isolates defined as Saprochaete species in Hacettepe University Hospitals Mycology Unit were included in the study. Species-level identification was confirmed by MALDITOF-MS and sequence analysis. Coagulase, hemolysis, phospholipase, secretory acid proteinase and esterase activity and biofilm forming ability were tested. Minimum inhibitory concentration (MIC) values of amphotericin B, fluconazole, voriconazole and micafungin were determined according to Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST). Of the isolates included in the study, 53 were identified as Saprochaete capitata and 4 as Saprochaete clavata. All isolates were negative for coagulase, hemolysis, phospholipase, and acid proteinase. Esterase positivity was 56.1% for all isolates. All isolates were strong biofilm positive by crystal violet and XTT methods. MIC90 values in antifungal susceptibility tests were 2 g/mL and 1 mg/l for amphotericin B, 8 g/mL and 32 mg/l for flucanozole, 0.25 g/ml and 4 mg/l for voriconazole, micafungin for CLSI and EUCAST, respectively.