Background Candida parapsilosis is a frequent cause of candidemia worldwide. Its incidence is associated with the use of medical implants, such as central venous catheters or parenteral nutrition. This species has reduced susceptibility to echinocandins and it is susceptible to polyenes and azoles. Multiple outbreaks caused by fluconazole non-susceptible strains have been reported recently. A similar trend has been observed among the C. parapsilosis isolates received in the last two years at the Spanish Mycology Reference Laboratory. Methods Yeast were identified by molecular biology and antifungal susceptibility testing was performed using EUCAST protocol. ERG11 gene was sequenced to identify resistance mechanisms, and strain typing was carried out by microsatellite analysis. Results We examined the susceptibility profile of 1,315 C. parapsilosis isolates available at our Reference Laboratory between 2000 and 2021, noticing an increase in the number of isolates with acquired resistance to fluconazole and voriconazole has increased in at least eight different Spanish hospitals in 2020-2021. From 121 recorded clones, 3 were identified as the most prevalent in Spain (clone 10 in Catalonia, and clone 96 in Castilla-Leon and Madrid, wereas clone 67 was found in two geographically unrelated regions, Cantabria and Balearic Islands). Conclusions Our data suggests that concurrently with the COVID-19 pandemic, a selection of fluconazole-resistant C. parapsilosis isolates has occurred in Spain, and the expansion of specific clones has been noted across centers. Further research is needed to determine the factors that underlie the successful expansion of these clones and their potential genetic relatedness.

In the last decade, Candida glabrata has become an important emerging opportunistic pathogen not only because of the increase in nosocomial infections frequency but also because of its ability to form biofilms and its innate resistance to commercial antifungals. These characteristics make this pathogen a major problem in hospital settings, including problems regarding equipment, and in immunosuppressed patients, who are at high risk for candidemia. Therefore, there is an urgent need for the development of and search for new antifungal drugs. In this study, the efficacy of two dendritic wedges with 4-phenyl butyric acid (PBA) at the focal point and cationic charges on the surface ArCO2G2(SNMe3I)4 (1) and ArCO2G3(SNMe3I)8 (2) was studied against C. glabrata strain to inhibit the formation of biofilms and eliminate established biofilm. For this, MBIC (minimum biofilm inhibitory concentration), MBDC (minimum biofilm damaging concentrations), as well as MFCB (minimum fungicidal concentration in biofilm) and MBEC (minimum biofilm eradicating concentration) were determined. In addition, different combinations of dendrons and amphotericin B were tested to study possible synergistic effects. On the other hand, cytotoxicity studies were performed. C. glabrata cells and biofilm structure were visualized by confocal microscopy. ArCO2G2(SNMe3I)4 (1) and ArCO2G3(SNMe3I)8 (2) dendrons showed both an MBIC of 8 mg/L and a MBDC of 32 mg/L and 64 mg/L, respectively. These dendrons managed to eradicate the entirety of an established biofilm. In combination with the antifungal amphotericin, it was possible to prevent the generation of biofilms and eradicate established biofilms at lower concentrations than those required individually for each compound at these conditions.

Background: Candida parapsilosis is a frequent cause of candidemia worldwide. Its incidence is associated with the use of medical implants, such as central venous catheters or parenteral nutrition. This species has reduced susceptibility to echinocandins and is susceptible to polyenes and azoles. Multiple outbreaks caused by fluconazole non-susceptible strains have been reported recently. A similar trend has been observed among the C. parapsilosis isolates received in the last two years at the Spanish Mycology Reference Laboratory. Methods: Yeast were identified by molecular biology and antifungal susceptibility testing was performed using EUCAST protocol. ERG11 gene was sequenced to identify resistance mechanisms, and typification was carried out by microsatellite analysis. Results: We examined the susceptibility profile of the C. parapsilosis isolates available at our Reference Laboratory since 2000 (around 1,300 strains). During the last two years, the number of isolates with acquired resistance to fluconazole and voriconazole has increased in at least eight different Spanish hospitals. Typification of the isolates revealed that some prevalent clones had spread through several hospitals of the same geographical region. One of these clones was found in hospitals from the region of Catalonia, another in hospitals from Madrid and Burgos, and two other different genotypes from Santander. Conclusions: Our data suggests that the epidemiological situation caused by the COVID-19 pandemic might have induced a selection of fluconazole-resistant C. parapsilosis isolates that were already present at the hospitals. Further measures must be taken to avoid the establishment of clinical outbreaks that could threaten the life of infected patients.