The black yeast genus Exophiala is known to cause a wide variety of diseases in severely ill individuals but can also affect immunocompetent individuals. Virulence markers and other physiological parameters were tested in eight clinical and 218 environmental strains, with a specific focus on human-dominated habitats for the latter. Urease and catalase were consistently present in all samples; four strains expressed proteinase and three strains expressed DNase, whereas none of the strains showed phospholipase, haemolysis, or co-haemolysis activities. Biofilm formation was identified in 30 (13.8%) of the environmental isolates, particularly in strains from dishwashers, and was noted in only two (25%) of the clinical strains. These results indicate that virulence factors are inconsistently present in the investigated Exophiala species, suggesting opportunism rather than pathogenicity.
Investigations of both virulence factors and antifungal susceptibility profiles are crucial for understanding the pathogenesis and prognosis of ophthalmic mycoses. In this study, we investigated the in vitro antifungal susceptibility of amphotericin B (AMB), voriconazole (VRC), and natamycin (NAT) against a set of 50 fungal isolates obtained from patients with ocular mycoses using the Clinical and Laboratory Standards Institute broth microdilution method. In addition, putative virulence factor, such as secretory phospholipases and proteinases, and biofilm formation activity were analyzed. The geometric means (GMs) of the minimum inhibitory concentrations (MICs) of the antifungals across all isolates were the following (in increasing order): VRC (0.70 μg/mL), AMB (0.81 μg/mL), and NAT (1.05 μg/mL). The highest activity against 14 Aspergillus strains was exhibited by VRC (GM MIC: 0.10 μg/mL), followed by AMB and NAT (GM MICs: 0.21 and 0.27 μg/mL), respectively. However, for 12 Fusarium spp., the GM MIC of VRC (2.66) was higher than those of NAT and AMB (GM MICs 1.3 and 0.8 μg/mL, respectively). Proteinase and phospholipase activity were observed in 30 % and 42 % of the isolates, respectively, whereas only 8 % of the isolates were able to produce biofilms. Phospholipase activity was observed in all Fusarium isolates, but not in any of the Aspergillus isolates. In contrast, biofilm-forming capability was detected in 25 % of the Fusarium isolates, but none of the Aspergillus isolates. The differences in the MICs of AMB, VRC, and NAT, biofilm-forming ability and proteinase and phospholipase activities among the isolates were not significant (p > 0.05). Overall, our study suggests no significant correlation between the antifungal susceptibility profiles and virulence attributes of ocular fungal isolates.
Background and aim: Infections caused by Candida species are significantly increasing today, and invasive Candida infections are generally associated with high mortality. Early diagnosis and identification of Candida spp. is important for the determination of antifungal agents that will be used for treatment. The aim of the present study was to provide a better regimen for Candida infections in the future. Materials and methods: The Sensititre YeastOne (SYO) method was compared with The Clinical Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) testing method. Endpoints of minimal inhibitory concentrations (MICs) were determined for both methods. Results: By using both methods, MIC values of micafungin, caspofungin, voriconazole, and fluconazole were lower than amphotericin B. The values obtained with the SYO method were in high categorical agreement for ecinocandins and amphotericin B. The results of voriconazole and fluconazole were in low categorical agreement. The categorical agreement between the SYO and the BMD results at 24 h was 82.1% for VORI and 98.4% for AMB. Values obtained with SYO method for all antifungal agents were in high essential agreement with the data of the CLSI reference BMD method. The essential agreement between the SYO and the BMD results at 24 h was 94.0% for MFG and 99.0% for AMB. Conclusions: The SYO method was ready-to use, so it appeared to be easier and more efficient for Candida isolates.
Background and Purpose: Scedosporium apiospermum complex as a ubiquitous environmental mold is increasingly reported to cause an invasive fungal infection in immunosuppressive hosts. Herein, we present the case of an immunosuppressive 54-year-old man who developed S. apiospermum complex lung infection and pulmonary adenocarcinoma. Case report: The patient had some complaints of dyspnea and cough during a neutropenic episode. The computed tomography (CT) scan of the patient revealed pleural effusion. After culturing the pleural fluid sample, the fungus was identified by microscopic examination and ITS sequencing. In addition, antifungal susceptibility testing was performed using the M38-A2 microdilution method. The minimum inhibitory concentrations of amphotericin B, voriconazole, posaconazole, and caspofungin were obtained as > 64, 0.06, 0.06, and 0.03 μg/mL, respectively. Voriconazole (administered in two doses of 6 mg/kg and a maximum of 250 mg) was preferred for treatment. The patient received antifungal treatment for 2 months; however, he was lost to follow-up. Conclusion: Scedosporium apiospermum complex should be considered a cause of systemic fungal infections in neutropenic patients. Furthermore, the determination of the in vitro antifungal susceptibilities of clinical strains may contribute to the development of therapeutic approaches.
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