Species distribution, azole resistance and related molecular mechanisms in invasive Candida parapsilosis complex isolates: Increase in fluconazole resistance in 21 years

Fluconazole-resistant Candida parapsilosis: fast detection of the Y132F ERG11p substitution, and a proposed microsatellite genotyping scheme

OBJECTIVES

We propose fast and accurate molecular detection of the Y132F ERG11p substitution directly on pure-cultured Candida parapsilosis isolates. We also assessed a discriminative genotyping scheme to track circulating genotypes.

METHODS

A total of 223 C. parapsilosis isolates (one patient each) from 20 hospitals, located in Spain and Italy were selected. Isolates were fluconazole-resistant (n = 94; harbouring the Y132F ERG11p substitution [n = 85], the G458S substitution [n = 6], the R398I substitution [n = 2], or the wild-type ERG11 gene sequence) or fluconazole-susceptible (n = 129). Two targeted-A395T-mutation PCR formats (conventional and real-time) were engineered and optimized on fluconazole-susceptible and fluconazole-resistant pure-cultured isolates, thus skipping DNA extraction. Two genotyping schemes were compared: Scheme 1 (CP1, CP4a, CP6, and B markers), and Scheme 2 (6A, 6B, 6C, CP1, CP4a, and CP6 markers).

RESULTS

The screening performed using both PCR formats showed 100% specificity (fluconazole-susceptible isolates; n = 129/129) and sensitivity (Y132F isolates; n = 85/85) values; however, results were available in 3 and 1.5 hours with the conventional and real-time PCR formats, respectively. Overall, Scheme 1 showed higher genetic diversity than Scheme 2, as shown by the number of alleles detected (n = 98; mean 23, range 13-38), the significantly higher observed and expected heterozygosity, and the probability of identity index (2.5 × 10-6). Scheme 2 markers did not provide further genotypic discrimination of Y132F fluconazole-resistant genotypes.

CONCLUSION

Both proposed PCR formats allow us to speed up the accurate detection of substitution Y132F ERG11p in C. parapsilosis isolates with 100% specificity and sensitivity. In addition, we recommend CP1, CP4a, CP6, and B microsatellite markers for genotyping fluconazole-resistant isolates.

Fluconazole-resistant Candida parapsilosis genotypes from hospitals located in five Spanish cities and one in Italy: Description of azole-resistance profiles associated with the Y132F ERG11p substitution

BACKGROUND

Fluconazole-resistant Candida parapsilosis is a matter of concern.

OBJECTIVES

To describe fluconazole-resistant C. parapsilosis genotypes circulating across hospitals in Spain and Rome and to study their azole-resistance profile associated with ERG11p substitutions.

PATIENTS/METHODS

We selected fluconazole-resistant C. parapsilosis isolates (n = 528 from 2019 to 2023; MIC ≥8 mg/L according to EUCAST) from patients admitted to 13 hospitals located in five Spanish cities and Rome. Additionally, we tested voriconazole, posaconazole, isavuconazole, amphotericin B, micafungin, anidulafungin and ibrexafungerp susceptibility.

RESULTS

Of the 53 genotypes found, 49 harboured the Y132F substitution, five of which were dominating city-specific genotypes involving almost half the isolates. Another genotype involved isolates harbouring the G458S substitution. Finally, we found two genotypes with the wild-type ERG11 gene sequence and one with the R398I substitution. All isolates were fully susceptible/wild-type to amphotericin B, anidulafungin, micafungin and ibrexafungerp. The azole-resistance patterns found were: voriconazole-resistant (74.1%) or voriconazole-intermediate (25.2%), posaconazole-resistant (10%) and isavuconazole non-wild-type (47.5%). Fluconazole-resistant and voriconazole non-wild-type isolates were likely to harbour substitution Y132F if posaconazole was wild type; however, if posaconazole was non-wild type, substitution G458S was indicated if isavuconazole MIC was >0.125 mg/L or substitution Y132F if isavuconazole MIC was ≤0.125 mg/L.

CONCLUSIONS

We detected a recent clonal spread of fluconazole-resistant C. parapsilosis across some cities in Spain, mostly driven by dominating city-specific genotypes, which involved a large number of isolates harbouring the Y132F ERG11p substitution. Isolates harbouring substitution Y132F can be suspected because they are non-susceptible to voriconazole and rarely posaconazole-resistant.

Culturable yeast diversity in urban topsoil influenced by various anthropogenic impacts

In urban ecosystems, processes associated with anthropogenic influences almost always lead to changes in soil micromycete complexes. The taxonomic structure of soil micromycete complexes is an important informative parameter of soil bioindication in the ecological control of urban environments. Unicellular fungi, such as culturable yeasts, are a very suitable and promising object of microbiological research for monitoring urban topsoil. This review aims to give an overview of the yeast communities in urban topsoil in different areas of Moscow (heating main area, household waste storage and disposal area, highway area) and to discuss the changes in the taxonomic structure of culturable yeast complexes depending on the type and intensity of anthropogenic impact.

Candida parapsilosis complex in the clinical setting

Representatives of the Candida parapsilosis complex are important yeast species causing human infections, including candidaemia as one of the leading diseases. This complex comprises C. parapsilosis, Candida orthopsilosis and Candida metapsilosis, and causes a wide range of clinical presentations from colonization to superficial and disseminated infections with a high prevalence in preterm-born infants and the potential to cause outbreaks in hospital settings. Compared with other Candida species, the C. parapsilosis complex shows high minimal inhibitory concentrations for echinocandin drugs due to a naturally occurring FKS1 polymorphism. The emergence of clonal outbreaks of strains with resistance to commonly used antifungals, such as fluconazole, is causing concern. In this Review, we present the latest medical data covering epidemiology, diagnosis, resistance and current treatment approaches for the C. parapsilosis complex. We describe its main clinical manifestations in adults and children and highlight new treatment options. We compare the three sister species, examining key elements of microbiology and clinical characteristics, including the population at risk, disease manifestation and colonization status. Finally, we provide a comprehensive resource for clinicians and researchers focusing on Candida species infections and the C. parapsilosis complex, aiming to bridge the emerging translational knowledge and future therapeutic challenges associated with this human pathogen.

In Vitro Susceptibility Tests in the Context of Antifungal Resistance: Beyond Minimum Inhibitory Concentration in Candida spp

Antimicrobial resistance is a matter of rising concern, especially in fungal diseases. Multiple reports all over the world are highlighting a worrisome increase in azole- and echinocandin-resistance among fungal pathogens, especially in Candida species, as reported in the recently published fungal pathogens priority list made by WHO. Despite continuous efforts and advances in infection control, development of new antifungal molecules, and research on molecular mechanisms of antifungal resistance made by the scientific community, trends in invasive fungal diseases and associated antifungal resistance are on the rise, hindering therapeutic options and clinical cures. In this context, in vitro susceptibility testing aimed at evaluating minimum inhibitory concentrations, is still a milestone in the management of fungal diseases. However, such testing is not the only type at a microbiologist's disposal. There are other adjunctive in vitro tests aimed at evaluating fungicidal activity of antifungal molecules and also exploring tolerance to antifungals. This plethora of in vitro tests are still left behind and performed only for research purposes, but their role in the context of invasive fungal diseases associated with antifungal resistance might add resourceful information to the clinical management of patients. The aim of this review was therefore to revise and explore all other in vitro tests that could be potentially implemented in current clinical practice in resistant and difficult-to-treat cases.

Mutations in TAC1 and ERG11 are major drivers of triazole antifungal resistance in clinical isolates of Candida parapsilosis

OBJECTIVES

The aim of this study was to determine how mutations in CpERG11 and CpTAC1 contribute to fluconazole resistance in a collection of clinical isolates.

METHODS

Sequences of CpERG11 and CpTAC1 were determined for 35 resistant Candida parapsilosis clinical isolates. A plasmid-based CRISPR-Cas9 system was used to introduce mutations leading to amino acid substitution in CpTac1 and CpErg11. Triazole susceptibility was determined by broth microdilution and E-test. Differential expression of genes mediated by CpTAC1 mutation was determined by RNA sequencing, and relative expression of individual transporter genes was assessed with RT-qPCR.

RESULTS

Six isolates carried a mutation in CpTAC1 in combination with the CpERG11 mutation, leading to the CpErg11Y132F substitution. When introduced into susceptible isolates, this CpERG11 mutation led to a 4- to 8-fold increase in fluconazole minimum inhibitory concentrations (MIC; 0.125 μg/mL vs. 0.5 μg/mL, 0.125 μg/mL vs. 0.5 μg/mL, and 0.5 μg/mL vs. 4 μg/mL). When introduced into a susceptible isolate, the CpTAC1 mutation leading to the G650E substitution resulted in an 8-fold increase in fluconazole MIC (0.25 μg/mL vs. 2 μg/mL), whereas correction of this mutation in resistant isolates led to a 16-fold reduction in MIC (32 μg/mL vs. 2 μg/mL). CpCDR1, CpCDR1B, and CpCDR1C were overexpressed in the presence CpTac1G650E. Disruption of these genes in combination resulted in a 4-fold reduction in fluconazole MIC (32 μg/mL vs. 8 μg/mL).

DISCUSSION

These results define the specific contribution made by the Y132F substitution in CpERG11 and demonstrate a role for activating mutations in CpTAC1 in triazole resistance in C. parapsilosis.

The role of fruits as reservoirs for resistant and virulent strains of opportunistic yeasts

Strains of the Candida parapsilosis and Meyerozyma guilliermondii species complexes isolated from the internal tissues of 26 fruit species from 21 countries were evaluated for their susceptibility to conventional antifungal compounds (fluconazole, voriconazole, amphotericin B) and hydrolytic activity. A total of 144 strains were studied. Resistance to at least one of the antifungal compounds tested was found in 26.4% of the endophytic strains examined. Most of the strains were insensitive to fluconazole. Multiresistance was detected only in two strains of C. parapsilosis sensu stricto from tropical apples. Phospholipase production and proteolytic and hemolytic activities were significantly higher in endophytes from tropical fruits. Resistant and virulent strains of opportunistic yeasts can thus spread worldwide via purchased fruit, which can harm people with a weakened immune status and children whose immune systems are not yet fully developed.

The Metschnikowia pulcherrima Clade as a Model for Assessing Inhibition of Candida spp. and the Toxicity of Its Metabolite, Pulcherrimin

Candidiasis is one of the most frequent infections worldwide. In this study, the antimicrobial properties of six strains belonging to the Metschnikowia pulcherrima clade were evaluated against twenty Candida and Candida-related Filobasidiella neoformans var. bacillispora (syn. Cryptococcus neoformans) of different origins, employing the agar cross method. The toxic effect of pulcherrimin, a red metabolite that is responsible for the antimicrobial activities of Metschnikowia spp., was evaluated in various experimental models. The results of agar tests showed that the selected M. pulcherrima strains inhibited the growth of the Candida and non-Candida strains. However, inhibition was dependent on the strain and the environment. The presence of peptone, sodium silicate, and a higher incubation temperature decreased the antifungal action of the M. pulcherrima strains. Pulcherrimin showed cytotoxic and antiproliferative activity, with oxidative stress in cells leading to apoptosis. More research is needed on the mechanism of action of pulcherrimin on somatic cells.

In vitro susceptibility profiles of Candida parapsilosis species complex subtypes from deep infections to nine antifungal drugs

Introduction. The Candida parapsilosis complex can be divided into C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis subtypes. It is uncommon for drug sensitivity tests to type them.Gap Statement. In routine susceptibility reports, drug susceptibility of C. parapsilosis complex subtypes is lacking.Aim. The aim of this study is to investigate the antifungal susceptibility and clinical distribution characteristics of the C. parapsilosis complex subtypes causing deep infection in patients.Methodology. Non-repetitive strains of C. parapsilosis complex isolated from deep infection from 2017 to 2019 were collected. Species-level identification was performed using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer and confirmed using ITS gene sequencing, when necessary. Antifungal susceptibility testing was performed using the Sensititre YeastOne system method.Results. A total of 244 cases were included in the study, including 176 males (72.13 %, 60.69±13.43 years) and 68 females (27.87 %, 60.21±10.59 years). The primary diseases were cancer (43.44 %), cardiovascular disease (25.00 %), digestive system diseases, (18.44 %), infection (6.97 %), and nephropathy (6.15 %). Strains were isolated from the bloodstream (63.11 %), central venous catheters (15.16 %), pus (6.56 %), ascites (5.74 %), sterile body fluid (5.33 %), and bronchoalveolar lavage fluid (BALF, 4.09 %). Of the 244 C. parapsilosis complex strains, 179 (73.26 %) were identified as C. parapsilosis sensu stricto, 62 (25.41 %) were C. orthopsilosis, and three (1.23 %) were C. metapsilosis. Only one C. parapsilosis sensu stricto strain was resistant to anidulafungin, micafungin, caspofungin, and voriconazole, and it was non-wild-type (NWT) to amphotericin B. Furthermore, six C. parapsilosis sensu stricto strains were resistant to fluconazole, and one was dose-dependent susceptible. Five C. parapsilosis sensu stricto strains were NWT to posaconazole. Only one C. orthopsilosis strain was NWT for anidulafungin, micafungin, caspofungin, fluconazole, voriconazole, amphotericin B, and posaconazole, while the rest of the strains were wild-type.Conclusion. C. parapsilosis sensu stricto was the main clinical isolate from the C. parapsilosis complex in our hospital. Most strains were isolated from the bloodstream. The susceptibility rate to commonly used antifungal drugs was more than 96 %. Furthermore, most of the infected patients were elderly male cancer patients.

Water Quality, Heavy Metals, and Antifungal Susceptibility to Fluconazole of Yeasts from Water Systems

Aquatic environments could be reservoirs of pathogenic yeasts with acquired antifungal resistance. The susceptibility to antifungal agents of yeasts present in the wastewater and natural waters of the city of Cali was evaluated. Samples were taken from two types of water: drinking water (Meléndez River, drinking water treatment plant "Puerto Mallarino" in the Cauca River) and wastewater (South Channel of the Cauca River, "Cañaveralejo-PTAR" wastewater treatment plant). Physico-chemical parameters, heavy metal concentration, and yeast levels were determined using standard procedures. Yeasts were identified using API 20 C AUX (BioMérieux) and sequence analysis of the ITS1-5.8S-ITS2 and D1/D2 regions of the large subunit of the ribosome. Susceptibility assays against fluconazole and amphotericin B using the minimum inhibitory concentration (MIC) test were determined using the microdilution method. The influence of physico-chemical parameters and heavy metals was established using principal component analysis (PCA). Yeast counts were higher at WWTP "PTAR" and lower at Melendez River, as expected. A total of 14 genera and 21 yeast species was identified, and the genus Candida was present at all locations. Susceptibility tests showed a 32.7% resistance profile to fluconazole in the order DWTP "Puerto Mallarino = WWTP "PTAR" > South Channel "Navarro". There were significant differences (p < 0.05) in the physico-chemical parameters/concentration of heavy metals and yeast levels between the aquatic systems under study. A positive association was observed between yeast levels and total dissolved solids, nitrate levels, and Cr at the "PTAR" WWTP; conductivity, Zn, and Cu in the South Channel; and the presence of Pb in the "Puerto Mallarino" DWTP. Rhodotorula mucilaginosa, Candida albicans, and Candida sp. 1 were influenced by Cr and Cd, and Diutina catelunata was influenced by Fe (p < 0.05). The water systems explored in this study showed different yeast levels and susceptibility profiles, and, therefore, possible genetic differences among populations of the same species, and different physico-chemical and heavy metals concentrations, which were probably modulating the antifungal-resistant yeasts. All these aquatic systems discharge their content into the Cauca River. We highlight the importance to further investigate if these resistant communities continue to other locations in the second largest river of Colombia and to determine the risk posed to humans and animals.

Scanning ion-conductance microscopy technique for studying the topography and mechanical properties of Candida parapsilosis yeast microorganisms

Super-resolution microscopy is widely used in the development of novel antimicrobial testing in vitro. In the presented work, a scanning protocol was developed by the method of scanning ion-conducting microscopy (SICM), which makes it possible to study microorganisms without rigid fixation and in saline, obtaining an index map of nanosized structures. The effect of azole and echinocandins drugs on the morphology and mechanical properties of Candida parapsilosis yeast was studied. The findings are consistent with previously proposed drug mechanisms and reports that have examined antifungal agents using AFM, SEM, and TEM. We have shown that the SICM method is capable of scanning and detecting the nanomechanical properties of yeast non-invasively.

Evaluation of candidemia in children at a university hospital: A retrospective cohort

BACKGROUND

Candidemia is a life-threatening infection in hospitalied children. This study aimed to evaluate candidemia's demographic and clinical characteristics and identify the risk factors and outcomes of Candida albicans (CA) and non-albicans Candida (NAC) spp.

METHODS

A retrospective cohort was designed to evaluate paediatric patients with candidemia between January 2008 and December 2020.

RESULTS

A total of 342 episodes in 311 patients were evaluated. The median age of the patients was 2.1 years (1 month-17 years and 6 months), and 59.6% were male. The prevalence of NAC (67.5%) candidemia was higher than that of CA (32.5%). The most commonly isolated Candida species was Candida parapsilosis (43.3%), followed by C. albicans (32.5%), Candida glabrata (6.1%) and Candida tropicalis (5.0%). The length of hospital stay prior to the positive culture and the total length of hospital stay were longer in the NAC group (p = .003 and p = .006). The neutrophil count was lower in the NAC group (p = .007). In the multivariate analysis, total parenteral nutrition, antifungal prophylaxis and a history of coagulase-negative staphylococci (CoNS) culture positivity in the past month were risk factors for developing candidemia due to NAC (p values were .003, .003 and .045). C. albicans and C. parapsilosis fluconazole resistance were 9.5% and 46.6%, respectively. The rates of amphotericin B resistance were 1.1% and 7.6% in C. albicans and C. parapsilosis, respectively. Mortality (14-day and 30-day) rates did not differ between the groups.

CONCLUSIONS

A history of CoNS culture positivity in the past month, total parenteral nutrition, and antifungal prophylaxis increases the risk of NAC candidemia.

Global Emergence of Resistance to Fluconazole and Voriconazole in Candida parapsilosis in Tertiary Hospitals in Spain During the COVID-19 Pandemic

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-nonsusceptible strains have been reported recently. A similar trend has been observed among the C. parapsilosis isolates received in the last 2 years at the Spanish Mycology Reference Laboratory.

METHODS

Yeast were identified by molecular biology, and antifungal susceptibility testing was performed using the European Committee on Antimicrobial Susceptibility Testing protocol. The ERG11 gene was sequenced to identify resistance mechanisms, and strain typing was carried out by microsatellite analysis.

RESULTS

We examined the susceptibility profile of 1315 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 8 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, whereas clone 67 was found in 2 geographically unrelated regions, Cantabria and the Balearic Islands).

CONCLUSIONS

Our data suggest that concurrently with the coronavirus disease 2019 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.

Fluconazole-resistant Candida parapsilosis: A new emerging threat in the fungi arena

Candida parapsilosis is a leading cause of invasive candidiasis in southern Europe, Latin America and Asia. C. parapsilosis has been mostly considered susceptible to triazoles, but fluconazole resistance is on the rise in some countries. The main mechanism related to fluconazole resistance is the presence of ERG11p substitutions, dominated by the Y132F amino acid substitution. Isolates harbouring this substitution mimic C. auris given that they may cause hospital outbreaks, become endemic, and emerge simultaneously in distant areas around the world. At the moment, Spain is experiencing a brusque emergence of fluconazole resistance in C. parapsilosis; isolates harbouring the Y132F substitution were detected for the first time in 2019. A recent study on Candida spp isolates from blood cultures collected in 16 hospitals located in the Madrid metropolitan area (2019 to 2021) reported that fluconazole resistance in C. parapsilosis reached as high as 13.6%. Resistance rates rose significantly during those three years: 3.8% in 2019, 5.7% in 2020, and 29.1% in 2021; resistant isolates harboured either the dominant Y132F substitution (a single clone found in four hospitals) or G458S (another clone found in a fifth hospital). The COVID-19 pandemic may have increased the number of candidaemia cases. The reason for such an increase might be a consequence of uncontrolled intra-hospital patient-to-patient transmission in some hospitals, as an increase not only in C. parapsilosis candidaemia episodes but also in the spread of clonal fluconazole-resistant isolates might have occurred in other hospitals during the pandemic period. Patients affected with fluconazole-resistant C. parapsilosis harbouring the Y132F substitution presented a mortality rate ranging from 9% to 78%, were mainly admitted to intensive care wards but did not have differential risk factors compared to those infected by susceptible isolates. With scarce exceptions, few patients (≤20%) infected with fluconazole-resistant isolates had previously received fluconazole, thus supporting the fact that, although fluconazole might have been a key factor to promote resistance, the main driver promoting the spread of fluconazole-resistant isolates was patient-to-patient transmission.

Global Prevalence of Antifungal-Resistant Candida parapsilosis: A Systematic Review and Meta-Analysis

A reliable estimate of Candida parapsilosis antifungal susceptibility in candidemia patients is increasingly important to track the spread of C. parapsilosis bloodstream infections and define the true burden of the ongoing antifungal resistance. A systematic review and meta-analysis (SRMA) were conducted aiming to estimate the global prevalence and identify patterns of antifungal resistance. A systematic literature search of the PubMed, Scopus, ScienceDirect and Google Scholar electronic databases was conducted on published studies that employed antifungal susceptibility testing (AFST) on clinical C. parapsilosis isolates globally. Seventy-nine eligible studies were included. Using meta-analysis of proportions, the overall pooled prevalence of three most important antifungal drugs; Fluconazole, Amphotericin B and Voriconazole resistant C. parapsilosis were calculated as 15.2% (95% CI: 9.2–21.2), 1.3% (95% CI: 0.0–2.9) and 4.7% (95% CI: 2.2–7.3), respectively. Based on study enrolment time, country/continent and AFST method, subgroup analyses were conducted for the three studied antifungals to determine sources of heterogeneity. Timeline and regional differences in C. parapsilosis prevalence of antifungal resistance were identified with the same patterns among the three antifungal drugs. These findings highlight the need to conduct further studies to assess and monitor the growing burden of antifungal resistance, to revise treatment guidelines and to implement regional surveillance to prevent further increase in C. parapsilosis drug resistance emerging recently.

Evidence of Fluconazole-Resistant Candida parapsilosis Genotypes Spreading across Hospitals Located in Madrid, Spain and Harboring the Y132F ERG11p Substitution

We have been monitoring the antifungal resistance in Candida parapsilosis isolates collected from inpatients at Madrid metropolitan area hospitals for the last 3 years. The study aimed to elucidate the presence of fluconazole-resistant C. parapsilosis genotypes in Madrid. From January 2019 to December 2021, a total of 354 C. parapsilosis isolates (n = 346 patients) from blood (76.6%) or intraabdominal samples were collected and genotyped using species-specific microsatellite markers. Antifungal susceptibilities to amphotericin B, the triazoles, micafungin, anidulafungin, and ibrexafungerp were performed according to EUCAST E.Def 7.3.2; the ERG11 gene was sequenced in fluconazole-resistant isolates. A total of 13.6% (n = 48/354) isolates (one per patient) were found to be resistant to fluconazole and non-wild-type to voriconazole but fully susceptible to ibrexafungerp. Resistant isolates were mostly sourced from blood (n = 45/48, 93.8%) and were detected in five hospitals. Two hospitals accounted for a high proportion of resistant isolates (n = 41/48). Resistant isolates harbored either the Y132F ERG11p amino acid substitution (n = 43) or the G458S substitution (n = 5). Isolates harboring the Y132F substitution clustered into a clonal complex involving three genotypes (one genotype accounted for n = 39/43 isolates) that were found in four hospitals. Isolates harboring the G458S substitution clustered into another genotype found in a fifth hospital. C. parapsilosis genotypes demonstrating resistance to fluconazole have been spreading across hospitals in Madrid, Spain. Over the last 3 years, the frequency of isolation of such isolates and the number of hospitals affected is on the rise.

Increasing Incidence and Shifting Epidemiology of Candidemia in Greece: Results from the First Nationwide 10-Year Survey

Globally, candidemia displays geographical variety in terms of epidemiology and incidence. In that respect, a nationwide Greek study was conducted, reporting the epidemiology of Candida bloodstream infections and susceptibility of isolates to antifungal agents providing evidence for empirical treatment. All microbiologically confirmed candidemia cases in patients hospitalized in 28 Greek centres during the period 2009–2018 were recorded. The study evaluated the incidence of infection/100,000 inhabitants, species distribution, and antifungal susceptibilities of isolated strains. Overall, 6057 candidemic episodes occurred during the study period, with 3% of them being mixed candidemias. The average annual incidence was 5.56/100,000 inhabitants, with significant increase over the years (p = 0.0002). C. parapsilosis species complex (SC) was the predominant causative agent (41%), followed by C. albicans (37%), C. glabrata SC (10%), C. tropicalis (7%), C. krusei (1%), and other rare Candida spp. (4%). C. albicans rates decreased from 2009 to 2018 (48% to 31%) in parallel with a doubling incidence of C. parapsilosis SC rates (28% to 49%, p < 0.0001). Resistance to amphotericin B and flucytosine was not observed. Resistance to fluconazole was detected in 20% of C. parapsilosis SC isolates, with a 4% of them being pan-azole-resistant. A considerable rising rate of resistance to this agent was observed over the study period (p < 0.0001). Echinocandin resistance was found in 3% of C. glabrata SC isolates, with 70% of them being pan-echinocandin-resistant. Resistance rate to this agent was stable over the study period. This is the first multicentre nationwide study demonstrating an increasing incidence of candidemia in Greece with a species shift toward C. parapsilosis SC. Although the overall antifungal resistance rates remain relatively low, fluconazole-resistant C. parapsilosis SC raises concern.

Antifungal Susceptibility Testing Identifies the Abdominal Cavity as a Source of Candida glabrata-Resistant Isolates

To identify unrecognized niches of resistant Candida isolates and compartmentalization, we retrospectively studied the antifungal susceptibility of 1,103 Candida spp. isolates from blood cultures, nonblood sterile samples, and nonsterile samples. Antifungal susceptibility was assessed by EUCAST E.Def 7.3.2; sequencing and genotyping of the fks1-2 and erg11 genes were carried out for non-wild-type isolates. Resistance compartmentalization (presence of resistant and susceptible isogenic isolates in different anatomical sites of a given patient) was studied. Clinical charts of patients carrying non-wild-type isolates were reviewed. Most isolates (63%) were Candida albicans, regardless the clinical source; Candida glabrata (27%) was the second most frequently found species in abdominal cavity samples. Fluconazole and echinocandin resistance rates were 1.5 and 1.3%, respectively, and were highest in C. glabrata. We found 22 genotypes among non-wild-type isolates, none of them widespread across the hospital. Fluconazole/echinocandin resistance rates of isolates from the abdominal cavity (3.2%/3.2%) tended to be higher than those from blood cultures (0.7%/1.3%). Overall, 15 patients with different forms of candidiasis were infected by resistant isolates, 80% of whom had received antifungals before or at the time of isolate collection; resistance compartmentalization was found in six patients, mainly due to C. glabrata. The highest antifungal resistance rate was detected in isolates from the abdominal cavity, mostly C. glabrata. Resistance was not caused by the spread of resistant clones but because of antifungal treatment. Resistance compartmentalization illustrates how resistance might be overlooked if susceptibility testing is restricted to bloodstream isolates.

Medicines for Malaria Venture COVID Box: a source for repurposing drugs with antifungal activity against human pathogenic fungi

BACKGROUND

Treatment of mycoses is often ineffective, usually prolonged, and has some side effects. These facts highlight the importance of discovering new molecules to treat fungal infections.

OBJECTIVES

To search the Medicines for Malaria Venture COVID Box for drugs with antifungal activity.

METHODS

Fourteen human pathogenic fungi were tested against the 160 drugs of this collection at 1.0 µM concentration. We evaluated the ability of the drugs to impair fungal growth, their fungicidal nature, and morphological changes caused to cells.

FINDINGS

Thirty-four molecules (21.25%) presented antifungal activity. Seven are antifungal drugs and one is the agricultural fungicide cycloheximide. The other drugs with antifungal activity included antibiotics (n = 3), antimalarials (n = 4), antivirals (n = 2), antiparasitcs (n = 3), antitumor agents (n = 5), nervous system agents (n = 3), immunosuppressants (n = 3), antivomiting (n = 1), antiasthmatic (n = 1), and a genetic disorder agent (n = 1). Several of these drugs inhibited Histoplasma capsulatum and Paracoccidioides brasiliensis growth (15 and 20, respectively), while Fusarium solani was not affected by the drugs tested. Most drugs were fungistatic, but niclosamide presented fungicidal activity against the three dimorphic fungi tested. Cyclosporine affected morphology of Cryptococcus neoformans.

MAIN CONCLUSIONS

These drugs represent new alternatives to the development of more accessible and effective therapies to treat human fungal infections.

Trends of the Epidemiology of Candidemia in Switzerland: A 15-Year FUNGINOS Survey

Background

The increasing incidence of candidemia and emergence of drug-resistant Candida species are major concerns worldwide. Long-term surveillance studies are needed.

Methods

The Fungal Infection Network of Switzerland (FUNGINOS) conducted a 15-year (2004–2018), nationwide, epidemiological study of candidemia. Hospital-based incidence of candidemia, Candida species distribution, antifungal susceptibility, and consumption were stratified in 3 periods (2004–2008, 2009–2013, 2014–2018). Population-based incidence over the period 2009–2018 derived from the Swiss Antibiotic Resistance Surveillance System (ANRESIS).

Results

A total of 2273 Candida blood isolates were studied. Population and hospital-based annual incidence of candidemia increased from 2.96 to 4.20/100 000 inhabitants (P = .022) and 0.86 to 0.99/10 000 patient-days (P = .124), respectively. The proportion of Candida albicans decreased significantly from 60% to 53% (P = .0023), whereas Candida glabrata increased from 18% to 27% (P < .0001). Other non-albicans Candida species remained stable. Candida glabrata bloodstream infections occurred predominantly in the age group 18–40 and above 65 years. A higher proportional increase of C glabrata was recorded in wards (18% to 29%, P < .0001) versus intensive care units (19% to 24%, P = .22). According to Clinical and Laboratory Standards Institute, nonsusceptibility to fluconazole in C albicans was observed in 1% of isolates, and anidulafungin and micafungin nonsusceptibility was observed in 2% of C albicans and C glabrata. Fluconazole consumption, the most frequently used antifungal, remained stable, whereas use of mold-active triazoles and echinocandins increased significantly in the last decade (P < .0001).

Conclusions

Over the 15-year period, the incidence of candidemia increased. A species shift toward C glabrata was recently observed, concurring with increased consumption of mold-active triazoles.