Efficacy of Voriconazole, Isavuconazole, Fluconazole, and Anidulafungin in the Treatment of Emerging Candida auris Using an Immunocompromised Murine Model of Disseminated Candidiasis.

Antifungal activity of anidulafungin, voriconazole, isavuconazole, and fluconazole in the treatment of Candida auris was determined in vitro and in vivo. MICs for anidulafungin, voriconazole, isavuconazole, fluconazole, and amphotericin B were 0.5, 1, >64, 0.25, and 4 µg/ml, respectively. Significant in vivo efficacy was observed in the anidulafungin- and voriconazole-treated groups in survival and reduction in kidney tissue fungal burden compared to that in the untreated group (P values of <0.001 and 0.044, respectively). Our data showed that anidulafungin and voriconazole had comparable efficacies against C. auris, whereas isavuconazole did not show significant in vivo activity.

Axillary Digital Thermometers uplifted a multidrug-susceptible Candida auris outbreak among COVID-19 patients in Brazil.

OBJECTIVES: To describe the first outbreak of Candida auris in Brazil, including epidemiological, clinical and microbiological data. METHODS: After the first Candida auris-colonised patient was diagnosed in a COVID-19 ICU at a hospital in Salvador, Brazil, a multidisciplinary team conducted a local C. auris prevalence investigation. Screening cultures for C. auris were collected from patients, healthcare workers and inanimate surfaces. Risk factors for C. auris colonisation were evaluated, and the fungemia episodes that occurred after the investigation were also analysed and described. Antifungal susceptibility of the C. auris isolates was determined, and they were genotyped with microsatellite analysis. RESULTS: Among body swabs collected from 47 patients, eight (n = 8/47, 17%) samples from the axillae were positive for C. auris. Among samples collected from inanimate surfaces, digital thermometers had the highest rate of positive cultures (n = 8/47, 17%). Antifungal susceptibility testing showed MICs of 0.5 to 1 mg/L for AMB, 0.03 to 0.06 mg/L for voriconazole, 2 to 4 mg/L for fluconazole and 0.03 to 0.06 mg/L for anidulafungin. Microsatellite analysis revealed that all C. auris isolates belong to the South Asian clade (Clade I) and had different genotypes. In multivariate analysis, having a colonised digital thermometer was the only independent risk factor associated with C. auris colonisation. Three episodes of C. auris fungemia occurred after the investigation, with 30-day attributable mortality of 33.3%. CONCLUSIONS: Emergence of C. auris in Salvador, Brazil, may be related to local C. auris clade I closely related genotypes. Contaminated axillary monitoring thermometers may facilitate the dissemination of C. auris reinforcing the concept that these reusable devices should be carefully cleaned with an effective disinfectant or replaced by other temperature monitoring methods.

Comparative Pharmacodynamics of Echinocandins against Aspergillus fumigatus Using an In Vitro Pharmacokinetic/Pharmacodynamic Model That Correlates with Clinical Response to Caspofungin Therapy: Is There a Place for Dose Optimization?

Echinocandins have been used as primary therapy of invasive aspergillosis (IA), with suboptimal results at standard dosing. Here, we explored the efficacy of dose escalation in a validated in vitro pharmacokinetic/pharmacodynamic (PK/PD) model. Six echinocandin wild-type (WT) and three non-WT A. fumigatus isolates were tested in an in vitro PK/PD model simulating anidulafungin, caspofungin, and micafungin exposures with a free drug maximum concentration (fCmax) of 0.01 to 16 mg/liter and a half-life (t1/2) of 8 to 22 h. The relationship between the area under the dosing interval time-free drug concentration curve (fAUC0-24)/minimum effective concentration (MEC) and % aberrant mycelium formation was analyzed. PK/PD indices associated with 50 to 99.99% maximal activity (EI50 to EI99.99) were correlated with the clinical outcome of a 50-mg/day standard dose of caspofungin. The probability of target attainment (PTA) was calculated for different dosing regimens of each echinocandin via Monte Carlo analysis. A sigmoidal PK/PD relationship was found for WT isolates with EI99 values of 766, 8.8, and 115 fAUC0-24/CLSI MEC for anidulafungin, caspofungin, and micafungin, respectively. No aberrant mycelia were observed for non-WT isolates, irrespective of their MEC and drug exposure. The EI99, EI99.9, and EI99.99 values corresponded to 2-, 3-, and 4-log10 formation of aberrant mycelia and correlated with survival, favorable, and complete response rates to caspofungin primary therapy in patients with IA. A very low PTA (<13%) was found for the standard doses of all echinocandins, whereas a PTA of ≥90% was found with 100 and 150 mg/day of caspofungin and 1,400 mg/day micafungin against WT isolates. For anidulafungin, the PTA for 1,500 mg/day was 10%. Among the three echinocandins, only caspofungin at 2 or 3 times the licensed dosing was associated with a high PTA. Caspofungin dose escalation might deserve clinical validation.

Preventing Candida albicans from subverting host plasminogen for invasive infection treatment.

Candida albicans is a common fungal pathogen in humans that colonizes the skin and mucosal surfaces of the majority healthy individuals. How C. albicans disseminates into the bloodstream and causes life-threatening systemic infections in immunocompromised patients remains unclear. Plasminogen system activation can degrade a variety of structural proteins in vivo and is involved in several homeostatic processes. Here, for the first time, we characterized that C. albicans could capture and "subvert" host plasminogen to invade host epithelial cell surface barriers through cell-wall localized Eno1 protein. We found that the "subverted" plasminogen system plays an important role in development of invasive infection caused by C. albicans in mice. Base on this finding, we discovered a mouse monoclonal antibody (mAb) 12D9 targeting C. albicans Eno1, with high affinity to the 254FYKDGKYDL262 motif in α-helices 6, ß-sheet 6 (H6S6) loop and direct blocking activity for C. albicans capture host plasminogen. mAb 12D9 could prevent C. albicans from invading human epithelial and endothelial cells, and displayed antifungal activity and synergistic effect with anidulafungin or fluconazole in proof-of-concept in vivo studies, suggesting that blocking the function of cell surface Eno1 was effective for controlling invasive infection caused by Candida spp. In summary, our study provides the evidence of C. albicans invading host by "subverting" plasminogen system, suggesting a potential novel treatment strategy for invasive fungal infections.

Acquisition of FKS2 mutation after echinocandin treatment of infective endocarditis by Candida glabrata.

Bloodstream infections caused by non-albicans Candida species are increasing and echinocandins have been extensively used especially in patients with hemodynamic instability, previous antifungal treatment and hospital risk factors for intrinsic or acquired resistance to azoles. Candida glabrata resistance to echinocandins is reported and is generally associated with previous use of echinocandins; FKS gene mutations have been associated with a worse outcome. We report the case of a 65-year-old woman who developed candidemia and endocarditis by C. glabrata with a newly acquired FKS mutation 24 months after successful treatment of infective endocarditis by C. glabrata with a double dosage of anidulafungin (200 mg daily) followed by oral voriconazole. Driven by high echinocandin MICs the strain taken by intraoperative cultures was further analyzed in a referral microbiology laboratory, confirming the new onset of point mutation S633P of the FKS2 gene.

First report on echinocandin resistant Polish Candida isolates.

PURPOSE: Candida spp. are ranked as one of the four major causative agents of fungal infections. The number of infections caused by Candida species resistant to fluconazole, which is applied as the first line drug in candidiasis treatment, increases every year. In such cases the application of echinocandin is necessary. Echinocandin susceptibility testing has become a routine laboratory practice in many countries due to the increasing frequency of clinical failures during treatment with these drugs. METHODS: We performed anidulafungin, micafungin and caspofungin susceptibility testing according to the microdilution broth method on 240 Candida isolates collected in Polish hospitals. RESULTS: We identified 12 isolates resistant to all echinocandins within 240 examined isolates. Moreover, 6 of the examined samples were identified as rare Candida species and among them we observed very high echinocandin MIC values. CONCLUSION: Our research proves that in Poland there is a problem of echinocandin resistance. Moreover, we identified two species of Candida which are rare causative agents of human infections, and there was no reported incidence of such infections in Poland until now.

Species distribution and antifungal drug susceptibilities of yeasts isolated from the blood samples of patients with candidemia.

Candida albicans is the most frequently isolated fungal species in hospital settings worldwide. However, non-albicans Candida species with decreased susceptibility to antifungals have emerged as an important cause of fungemia. The aims of this study were to determine the species distribution of fungi isolated from the blood samples of patients at a Swedish University Hospital and to define the in vitro susceptibilities of these isolates to nine antifungal agents. In total, 233 yeast isolates from 143 patients were included in this study. Antifungal susceptibility testing was performed using broth dilution Sensititre YeastOne panels, which comprised amphotericin B, 5-flucytosine, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, micafungin, and caspofungin. The most common species in all age groups was C. albicans (n = 93, 65%), followed by C. glabrata (n = 27, 19%) and C. parapsilosis (n = 15, 10%). C. glabrata was mostly found in elderly individuals, while C. parapsilosis was found mainly in young children (p = 0.008). Antifungal resistance was low in the Candida species, except for reduced susceptibility to fluconazole among C. glabrata strains. C. albicans is the most frequent colonizer of Swedish patients. In general antifungal resistance is uncommon in Candida species. Nevertheless, reduced susceptibilities to fluconazole and echinocandins were found in C. glabrata and C. parapsilosis, respectively.

Postantifungal effect of anidulafungin against Candida albicans, Candida dubliniensis, Candida africana, Candida parapsilosis, Candida metapsilosis and Candida orthopsilosis.

OBJECTIVE: Candida albicans remains the most common aetiology of invasive candidiasis, leading to high morbidity and mortality. Nevertheless, the incidence of candidiasis due to non-C. albicans species, such as Candida parapsilosis, is increasing. Postantifungal effect (PAFE) is relevant for establishing dosage schedules in antifungal therapy, as the frequency of antifungal administration could change depending on PAFE. The aim of this study was to evaluate the PAFE of anidulafungin against C. albicans, Candida dubliniensis, Candida africana, C. parapsilosis, Candida metapsilosis and Candida orthopsilosis. METHODS: Twenty-one Candida strains were evaluated. Cells were exposed to anidulafungin for 1 h at concentrations ranging from 0.12 to 8 mg/L for PAFE studies. Time-kill experiments (TK) were conducted at the same concentrations. The experiments were performed using an inoculum of 1-5 x 105 cells/mL and 48 h incubation. Readings of PAFE and TK were done at 0, 2, 4, 6, 24 and 48 h. RESULTS: Anidulafungin was fungicidal against 2 out of 14 (14%) strains of C. albicans related species in PAFE experiments. Moreover, 2 mg/L of anidulafungin exerted a prolonged PAFE (≥ 33.6 h) against 13 out of 14 (93%) strains. Similarly, fungicidal endpoint was achieved against 1 out of 7 (14%) strains of C. parapsilosis complex, being PAFE prolonged (≥ 42 h) against 6 out of 7 (86%) strains. CONCLUSIONS: Anidulafungin induced a significant and prolonged PAFE against C. albicans and C. parapsilosis and their related species.

Therapeutic tools for oral candidiasis: Current and new antifungal drugs.

BACKGROUND: Candidiasis is one of the most common opportunistic oral infections that presents different acute and chronic clinical presentations with diverse diagnostic and therapeutic approaches. The present study carries out a bibliographic review on the therapeutic tools available against oral candidiasis and their usefulness in each clinical situation. MATERIAL AND METHODS: Recent studies on treatment of oral candidiasis were retrieved from PubMed and Cochrane Library. RESULTS: Nystatin and miconazole are the most commonly used topical antifungal drugs. Both antifungal drugs are very effective but need a long time of use to eradicate the infection. The pharmacological presentations of miconazole are more comfortable for patients but this drug may interact with other drugs and this fact should be assessed before use. Other topical alternatives for oral candidiasis, such as amphotericin B or clotrimazole, are not available in many countries. Oral fluconazole is effective in treating oral candidiasis that does not respond to topical treatment. Other systemic treatment alternatives, oral or intravenous, less used are itraconazole, voriconazole or posaconazole. Available novelties include echinocandins (anidulafungin, caspofungin) and isavuconazole. Echinocandins can only be used intravenously. Isavuconazole is available for oral and intravenous use. Other hopeful alternatives are new drugs, such as ibrexafungerp, or the use of antibodies, cytokines and antimicrobial peptides. CONCLUSIONS: Nystatin, miconazole, and fluconazole are very effective for treating oral candidiasis. There are systemic alternatives for treating recalcitrant infections, such as the new triazoles, echinocandins, or lipidic presentations of amphotericin B.

Delay in effective therapy in anidulafungin-resistant Candida tropicalis fungaemia: Potential for rapid prediction of antifungal resistance with whole-genome-sequencing.

OBJECTIVES: This study investigated the feasibility of using whole-genome sequencing (WGS) for the prediction of antifungal resistance in anidulafungin-resistant Candida tropicalis candidaemia isolates. METHODS: Next-generation sequencing was performed for three anidulafungin-resistant C. tropicalis isolates on an Illumina MiSeq system with in-house bioinformatics analysis. RESULTS: Mutations in Fks1p associated with anidulafungin resistance were identified. Other mutations associated with varying levels of phenotypic resistance to fluconazole were also identified. CONCLUSIONS: These data demonstrate the potential to predict antifungal resistance using WGS. With improving technology, real-time WGS may be used for tailoring effective antifungal therapy in patients with candidaemia.

Anidulafungin for the treatment of candidaemia caused by Candida parapsilosis: Analysis of pooled data from six prospective clinical studies.

Concerns with echinocandin use for infections caused by Candida parapsilosis complex species have driven the need for data to support echinocandin clinical efficacy in such patients. Data from six prospective studies were pooled to assess efficacy and safety of anidulafungin in patients with candidaemia caused by C. parapsilosis. Patient-level data were pooled from patients with microbiologically confirmed candidaemia due to C. parapsilosis treated with anidulafungin. Patients received a 200 mg intravenous (IV) loading dose of anidulafungin (day 1) and 100 mg daily thereafter. IV treatment could be switched to oral azole therapy after ≥5 or ≥10 days. Primary endpoint was global response at end of IV therapy (EOIVT). Seventy patients had candidaemia caused by C. parapsilosis. Global response was 77.1% (95% CI: 67.3, 87.0) at EOIVT and 70.0% (95% CI: 59.3, 80.7) at end of treatment. Three of 55 isolates (with MICs available) were resistant to anidulafungin (MIC ≥8 mg/L). All-cause mortality was 5.7% (n=4/70) by day 14 and 14.3% (n=10/70) by day 28. IV anidulafungin was effective for the treatment of C. parapsilosis candidaemia in this population, consistent with efficacy previously demonstrated for other Candida species. (ClinicalTrials.gov identifiers: NCT00496197, NCT00548262, NCT00537329, NCT00689338, NCT00806351, NCT00805740).

Epidemiology of candidemia and antifungal susceptibility in invasive Candida species in the Asia-Pacific region.

In the Asia-Pacific region, Candida albicans is the predominant Candida species causing invasive candidiasis/candidemia in Australia, Japan, Korea, Hong Kong, Malaysia, Singapore and Thailand whereas C. tropicalis is the most frequently encountered Candida species in Pakistan and India. Invasive isolates of C. albicans, C. parapsilosis complex and C. tropicalis remain highly susceptible to fluconazole (>90% susceptible). Fluconazole resistance (6.8-15%), isolates with the non-wild-type phenotype for itraconazole susceptibility (3.9-10%) and voriconazole (5-17.8%), and echinocandin resistance (2.1-2.2% in anidulafungin and 2.2% in micafungin) among invasive C. glabrata complex isolates are increasing in prevalence. Moreover, not all isolates of C. tropicalis have been shown to be susceptible to fluconazole (nonsusceptible rate, 5.7-11.6% in China) or voriconazole (nonsusceptible rate, 5.7-9.6% in China).

Efficacy of anidulafungin in the treatment of experimental Candida parapsilosis catheter infection using an antifungal-lock technique.

OBJECTIVES: The effectiveness of anidulafungin versus liposomal amphotericin B (LAmB) for treating experimental Candida parapsilosis catheter-related infection by an antifungal-lock technique was assessed. METHODS: Two clinical strains of C. parapsilosis (CP12 and CP54) were studied. In vitro studies were used to determine the biofilm MICs (MBIC50 and MBIC90) by XTT reduction assay and LIVE/DEAD biofilm viability for anidulafungin and LAmB on 96-well microtitre polystyrene plates and silicone discs. An intravenous catheter was implanted in New Zealand white rabbits. Infection was induced by locking the catheter for 48 h with the inoculum. The 48 h antifungal-lock treatment groups included control, 3.3 mg/mL anidulafungin and 5.5 mg/mL LAmB. RESULTS: Anidulafungin showed better in vitro activity than LAmB against C. parapsilosis growing in biofilm on silicone discs. MBIC90 of LAmB: CP12, >1024 mg/L; CP54, >1024 mg/L. MBIC90 of anidulafungin: CP12, 1 mg/L; CP54, 1 mg/L (P ≤ 0.05). Moreover, only anidulafungin (1 mg/L) showed >90% non-viable cells in the LIVE/DEAD biofilm viability assay on silicone discs. No differences were observed between the in vitro susceptibility of anidulafungin or LAmB when 96-well plates were used. Anidulafungin achieved significant reductions relative to LAmB in log10 cfu recovered from the catheter tips for both strains (P ≤ 0.05). Only anidulafungin achieved negative catheter tip cultures (CP12 63%, CP54 73%, P ≤ 0.05). CONCLUSIONS: Silicone discs may be a more reliable substrate for the study of in vitro biofilm susceptibility of C. parapsilosis. Anidulafungin-lock therapy showed the highest activity for experimental catheter-related infection with C. parapsilosis.

The Role of Echinocandins in Candida Biofilm-Related Vascular Catheter Infections: In Vitro and In Vivo Model Systems.

Candida biofilm-associated infections of central venous catheters are a challenging therapeutic problem. Recent in vitro and in vivo studies of the structure, formation, pathogenesis, and treatment establish a rationale for new approaches to management of these tenacious infections.

Role of Echinocandins in Fungal Biofilm-Related Disease: Vascular Catheter-Related Infections, Immunomodulation, and Mucosal Surfaces.

Biofilm-related infections have become an increasingly important clinical problem. Many of these infections occur in patients with multiple comorbidities or with impaired immunity. Echinocandins (caspofungin, micafungin, and anidulafungin) exert their fungicidal activity by inhibition of the synthesis of the (1→3)-ß-d-glucan. They are active among in vitro and in vivo model systems against a number of Candida species and filamentous fungi in their planktonic and biofilm phenotype. Their superior activity against biofilms poses them in an advantageous position among the antifungal armamentarium. However, additional studies are warranted to expand our knowledge on the role of echinocandins against biofilm-related infections.

Assessment of echinocandin regimens by pharmacokinetic/pharmacodynamic analysis against Candida spp. in paediatric patients.

This study aimed to investigate the cumulative fraction of response of various echinocandin (caspofungin, micafungin and anidulafungin) dosing regimens against Candida spp. in paediatric patients with invasive fungal infections (IFIs). Monte Carlo simulations were performed using previously published pharmacokinetic parameters and pharmacodynamic data to evaluate the ability of each echinocandin regimen in terms of fAUC/MIC (free drug area under the concentration-time curve/minimum inhibition concentration ratio) targets of caspofungin, micafungin and anidulafungin. Pharmacodynamic targets were attained in paediatric patients by both caspofungin regimens as well as by a high micafungin dosing regimens against Candida albicans and Candida glabrata. However, the results for anidulafungin suggested that the dosing regimens recommended were not optimal for paediatric patients. In addition, the predicted efficacy of all of the echinocandins against Candida parapsilosis was low. This is the first study to assess caspofungin, micafungin and anidulafungin therapy using Monte Carlo simulation. These results rationalise and optimise the dosage regimens of caspofungin, micafungin and anidulafungin against C. albicans, C. glabrata and C. parapsilosis for paediatric patients with IFIs.

Calcium-Mediated Induction of Paradoxical Growth following Caspofungin Treatment Is Associated with Calcineurin Activation and Phosphorylation in Aspergillus fumigatus.

The echinocandin antifungal drug caspofungin at high concentrations reverses the growth inhibition of Aspergillus fumigatus, a phenomenon known as the "paradoxical effect," which is not consistently observed with other echinocandins (micafungin and anidulafungin). Previous studies of A. fumigatus revealed the loss of the paradoxical effect following pharmacological or genetic inhibition of calcineurin, yet the underlying mechanism is poorly understood. Here, we utilized a codon-optimized bioluminescent Ca(2+) reporter aequorin expression system in A. fumigatus and showed that caspofungin elicits a transient increase in cytosolic free Ca(2+) ([Ca(2+)]c) in the fungus that acts as the initial trigger of the paradoxical effect by activating calmodulin-calcineurin signaling. While the increase in [Ca(2+)]c was also observed upon treatment with micafungin, another echinocandin without the paradoxical effect, a higher [Ca(2+)]c increase was noted with the paradoxical-growth concentration of caspofungin. Treatments with a Ca(2+)-selective chelator, BAPTA [1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid], or the L-type Ca(2+) channel blocker verapamil abolished caspofungin-mediated paradoxical growth in both the wild-type and the echinocandin-resistant (EMFR-S678P) strains. Concomitant with increased [Ca(2+)]c levels at higher concentrations of caspofungin, calmodulin and calcineurin gene expression was enhanced. Phosphoproteomic analysis revealed that calcineurin is activated through phosphorylation at its serine-proline-rich region (SPRR), a domain previously shown to be essential for regulation of hyphal growth, only at a paradoxical-growth concentration of caspofungin. Our results indicate that as opposed to micafungin, the increased [Ca(2+)]c at high concentrations of caspofungin activates calmodulin-calcineurin signaling at both a transcriptional and a posttranslational level and ultimately leads to paradoxical fungal growth.

Impact of special patient populations on the pharmacokinetics of echinocandins.

Echinocandins belong to the class of antifungal agents. Currently, three echinocandin drugs are licensed for intravenous treatment of invasive fungal infections: anidulafungin, caspofungin and micafungin. While their antifungal activity overlaps, there are substantial differences in pharmacokinetics (PK). Numerous factors may account for variability in PK of echinocandins including age (pediatrics vs adults), body surface area and body composition (normal weight vs obesity), disease status (e.g., critically ill and burn patients) and organ dysfunction (kidney and liver impairment). Subsequent effects of altered exposure might impact efficacy and safety. Knowledge of PK behavior is crucial in optimal clinical utilization of echinocandin in a specific patient or patient population. This review provides up-to-date information on PK data of anidulafungin, caspofungin and micafungin in special patient populations. Patient populations addressed are neonates, children and adolescents, obese patients, patients with hepatic or renal impairment, critically ill patients (including burn patients) and patients with hematological diseases.

Therapies against murine Candida guilliermondii infection, relationship between in vitro antifungal pharmacodynamics and outcome.

BACKGROUND: Candida guilliermondii has been recognized as an emerging pathogen showing a decreased susceptibility to fluconazole and considerably high echinocandin MICs. AIMS: Evaluate the in vitro activity of anidulafungin in comparison to amphotericin B and fluconazole against different isolates of C. guilliermondii, and their efficacy in an immunosuppressed murine model of disseminated infection. METHODS: The in vitro susceptibility of four strains against amphotericin B, fluconazole and anidulafungin was performed by using a reference broth microdilution method and time-kill curves. The in vivo efficacy was evaluated by determination of fungal load reduction in kidneys of infected animals receiving deoxycholate AMB at 0,8 mg/kg i.v., liposomal amphotericin B at 10 mg/kg i.v., fluconazole at 50 mg/kg, or anidulafungin at 10 mg/kg. RESULTS: Amphotericin B and anidulafungin showed fungicidal activity, while fluconazole was fungistatic for all the strains. In the murine model, liposomal amphotericin B at 10 mg/kg/day was effective in reducing the tissue burden in kidneys of mice infected with any of the tested strains. However, amphotericin B, anidulafungin and fluconazole were only effective against those strains showing low MIC values. CONCLUSIONS: Liposomal amphotericin B showed the higher activity and efficacy against the two strains of C. guilliermondii, in contrast to the poor effect of fluconazole and anidulafungin. Further studies with more isolates of C. guilliermondii representing a wider range of MICs should be carried out to assess whether there is any relationship between MIC values and anidulafungin efficacy.