Comparison of simulated candidemia detection during prophylactic antifungal therapy.

BACKGROUND: We investigated the neutralization performance of various automated blood culture systems for antifungal agents with regard to the most commonly isolated Candida species. METHODS: In this study, we evaluated the time to detection (TTD) of simulated candidemia for 6 Candida spp. (C. albicans, C. auris, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis) in 3 automated blood culture systems (BACTEC™ FX, BACT/ALERT® 3D, and BACT/ALERT® VIRTUO®), with or without trough and peak levels of eight antifungal agents (amphotericin B, anidulafungin, caspofungin, fluconazole, itraconazole, micafungin, posaconazole, and voriconazole). RESULTS: Caspofungin and micafungin significantly prolonged the TTDs for most of the tested strains in the 3 blood culture instruments, especially at peak concentrations. CONCLUSION: Peak concentrations of caspofungin and micafungin influence the performance of blood culture detection systems. Therefore, one should be careful about the possibility of prolonged TTDs for candidemia when using the abovementioned antifungal agents.

Therapeutic Potential of Fosmanogepix (APX001) for Intra-abdominal Candidiasis: from Lesion Penetration to Efficacy in a Mouse Model.

Intra-abdominal candidiasis (IAC) is one of the most common yet underappreciated forms of invasive candidiasis. IAC is difficult to treat, and therapeutic failure and drug-resistant breakthrough infections are common in some institutions despite the use of echinocandins as first-line agents. Fosmanogepix (FMGX, formerly APX001) is a first-in-class antifungal prodrug that can be administered both intravenously and orally. FMGX is currently in phase 2 clinical development for the treatment of life-threatening invasive fungal infections. To explore the pharmacological properties and therapeutic potential of FMGX for IAC, we evaluated both drug penetration and efficacy of the active moiety manogepix (MGX, formerly APX001A) in liver tissues in a clinically relevant IAC mouse model infected with Candida albicans Matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) and laser capture microdissection (LCM)-directed absolute drug quantitation were employed to evaluate drug penetration into liver abscess lesions both spatially and quantitatively. The partitioning of MGX into lesions occurred slowly after a single dose; however, robust accumulation in the lesion was achieved after 3 days of repeated dosing. Associated with this drug penetration pattern, reduction in fungal burden and clearance in the liver were observed in mice receiving the multiday FMGX regimen. In comparison, administration of micafungin resulted in marginal reduction in fungal burden at the end of 4 days of treatment. These results suggest that FMGX is a promising candidate for the treatment of IAC.

Rhizopus Infection in a Preterm Infant: A Novel Use of Posaconazole.

Posaconazole is a triazole antifungal with activity against Rhizopus, but data on its use and pharmacokinetics in preterm infants are scarce. In this case, a 24 4/7-week neonate's Rhizopus infection is successfully treated with debridement and combination antifungal therapy with amphotericin B, micafungin and enteral posaconazole. This is the first reported posaconazole use in a preterm neonate with Rhizopus.

In Vitro Evaluation of Antifungal Drug Combinations against Multidrug-Resistant Candida auris Isolates from New York Outbreak.

Since 2016, New York hospitals and health care facilities have faced an unprecedented outbreak of the pathogenic yeast Candida auris We tested over 1,000 C. auris isolates from affected facilities and found high resistance to fluconazole (MIC > 256 mg/liter) and variable resistance to other antifungal drugs. Therefore, we tested if two-drug combinations are effective in vitro against multidrug-resistant C. auris Broth microdilution antifungal combination plates were custom manufactured by TREK Diagnostic System. We used 100% inhibition endpoints for the drug combination as reported earlier for the intra- and interlaboratory agreements against Candida species. The results were derived from 12,960 readings, for 15 C. auris isolates tested against 864 two-drug antifungal combinations for nine antifungal drugs. Flucytosine (5FC) at 1.0 mg/liter potentiated the most combinations. For nine C. auris isolates resistant to amphotericin B (AMB; MIC ≥ 2.0 mg/liter), AMB-5FC (0.25/1.0 mg/liter) yielded 100% inhibition. Six C. auris isolates resistant to three echinocandins (anidulafungin [AFG], MIC ≥ 4.0 mg/liter; caspofungin [CAS], MIC ≥ 2.0 mg/liter; and micafungin [MFG], MIC ≥ 4.0 mg/liter) were 100% inhibited by AFG-5FC and CAS-5FC (0.0078/1 mg/liter) and MFG-5FC (0.12/1 mg/liter). None of the combinations were effective for C. auris 18-1 and 18-13 (fluconazole [FLC] > 256 mg/liter, 5FC > 32 mg/liter) except MFG-5FC (0.1/0.06 mg/liter). Thirteen isolates with a high voriconazole (VRC) MIC (>2 mg/liter) were 100% inhibited by the VRC-5FC (0.015/1 mg/liter). The simplified two-drug combination susceptibility test format would permit laboratories to provide clinicians and public health experts with additional data to manage multidrug-resistant C. auris.

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.

Synergistic effect of nikkomycin Z with caspofungin and micafungin against Candida albicans and Candida parapsilosis biofilms.

Antifungal lock therapy has received significant interest in the last few years because the frequently usage of intravascular devices is associated with an increasing number of catheter-related bloodstream infections caused by Candida species. Antifungal combinations with synergistic interaction can be a good choice for antifungal lock therapy; therefore, interactions were examined between two echinocandins (caspofungin and micafungin) and the chitin synthesis inhibitor nikkomycin Z against Candida albicans and C. parapsilosis biofilms. Susceptibility was evaluated using the XTT-based checkerboard microdilution method, while the nature of interactions was assessed by calculating fractional inhibitory concentration indices and using the Bliss independence model. Mathematic-based evaluations were supplemented with fluorescent LIVE/DEAD viability assay. The results obtained by statistical interaction analyses correlated well with the viability assay. The tested echinocandins with nikkomycin Z caused an extended cell death and the structure of the biofilm was sparse compared to the control, especially for C. albicans. The findings support the simultaneous usage of nikkomycin Z and caspofungin or micafungin in alternative therapies such as the antifungal lock therapy. SIGNIFICANCE AND IMPACT OF THE STUDY: Antifungal lock therapy can be a potential therapeutic approach to eradicate the intraluminal Candida biofilms; however, there is no approved lock strategy against fungal species so far. The results of this study provide valuable evidence that nikkomycin Z acts synergistically in combination with caspofungin or micafungin against biofilms. In addition, this synergy was more pronounced for micafungin combined with nikkomycin Z. Therefore, nikkomycin Z can be considered as a potential agent in antifungal lock therapy especially with micafungin against C. albicans or C. parapsilosis biofilms.

MSG-10: a Phase 2 study of oral ibrexafungerp (SCY-078) following initial echinocandin therapy in non-neutropenic patients with invasive candidiasis.

OBJECTIVES: To evaluate the safety and efficacy of two dosing regimens of oral ibrexafungerp (formerly SCY-078), a novel orally bioavailable ß-glucan synthase inhibitor, in subjects with invasive candidiasis versus the standard of care (SOC) and to identify the dose to achieve target exposure (15.4 µM·h) in >80% of the intended population. METHODS: In a multinational, open-label study, patients with documented invasive candidiasis were randomized to receive step-down therapy to one of three treatment arms: two dosing regimens of novel oral ibrexafungerp or the SOC treatment following initial echinocandin therapy. Plasma samples were collected to evaluate exposure by population pharmacokinetic (PK) modelling. Safety was assessed throughout the study and global response at the end of treatment. RESULTS: Out of 27 subjects enrolled, 7 received ibrexafungerp 500 mg, 7 received ibrexafungerp 750 mg and 8 received the SOC. Five did not meet criteria for randomization. Population PK analysis indicated that an ibrexafungerp 750 mg regimen is predicted to achieve the target exposure in ∼85% of the population. The rate of adverse events was similar among patients receiving ibrexafungerp or fluconazole. Similar favourable response rates were reported among all groups: 86% (n = 6) in the ibrexafungerp 750 mg versus 71% (n = 5) in both the fluconazole and ibrexafungerp 500 mg treatment arms. The one subject treated with continued micafungin had a favourable global response. CONCLUSIONS: The oral ibrexafungerp dose estimated to achieve the target exposure in subjects with invasive candidiasis is 750 mg daily. This dose was well tolerated and achieved a favourable global response rate, similar to the SOC.

Successful eradication of chronic symptomatic Candida krusei urinary tract infection with increased dose micafungin in a liver and kidney transplant recipient: Case report and review of the literature.

Treatment of symptomatic candiduria is notoriously challenging because of the limited repository of antifungals that achieve adequate urinary concentrations. Fluconazole, amphotericin B-based products, and flucytosine are established treatment options for most Candida species. Candida krusei exhibits intrinsic resistance to fluconazole and decreased susceptibility to amphotericin B and flucytosine. In transplant patients, both amphotericin B-based products and flucytosine are less desirable because of their toxicities. Other triazole antifungals are unappealing because they do not achieve adequate urinary concentrations, have multiple toxicities, and interact with transplant-related immunosuppressive medications. Echinocandins are well-tolerated but have been traditionally deferred in the treatment of symptomatic funguria because of their poor urinary concentrations but there is a small but emerging body of literature supporting their use. Here, we present a case of successful eradication of chronic symptomatic C krusei urinary tract infection with micafungin 150 milligrams daily in a liver and kidney transplant recipient, and we review the literature on treatment of symptomatic candiduria.

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.

Micafungin may be safely administered as outpatient parenteral antimicrobial therapy for chronic pulmonary aspergillosis.

BACKGROUND: Intravenous micafungin has been reported as a treatment alternative in patients with chronic pulmonary aspergillosis (CPA) where long-term oral triazole therapy is unfeasible. OBJECTIVES: We evaluated the safety and efficacy of micafungin administered via the outpatient parenteral antimicrobial therapy (OPAT) service for the treatment of CPA. METHODS: We included all CPA patients who received micafungin via OPAT between April 2016 and March 2018. Data on adverse events and line-related complications, and Quality of Life (QoL) scores at the start of micafungin course and 3 months later were extracted. Improvements in QoL were defined as an improvement of ≥4 points in at least one modality (symptom, impact, activity, total) in the St George's QoL score. A stable QoL score was defined as a change in score of <4 points in either direction whilst deterioration was defined as an increase of ≥4 points. RESULTS: There were 20 OPAT episodes involving 18 patients with a median duration of micafungin therapy of 21 (range: 4-248) days. Improvement or stability in the symptoms, activity, impact and total score was seen in 14 (78%), 12 (67%), 9 (50%) and 9 (50%) of the patients, respectively. However, half of the patients reported deterioration in the impact domain and total scores. By self-assessment, patients who categorised themselves as "poor" were comparable at the start of OPAT and at 3 months (43% vs 50%, McNemar's P = 0.7). Adverse events attributable to micafungin were recorded in 3 (14.3%) episodes. CONCLUSIONS: Micafungin may be safely administered via an OPAT service. Micafungin therapy was associated with an improvement or stability in QoL scores in at least 50% of the patients across the four domains.

Poor in vivo efficacy of caspofungin, micafungin and amphotericin B against wild-type Candida krusei clinical isolates does not correlate with in vitro susceptibility results.

We determined micafungin, caspofungin and amphotericin B (AMB) minimum inhibitory concentration (MICs) and killing rates in RPMI-1640 and in RPMI-1640 with 50% serum against three Candida krusei bloodstream isolates. MIC ranges in RPMI-1640 were 0.125-0.25, 0.25 and 0.125-0.5 mg/L, in RPMI-1640 with 50% serum, MICs were 64-128-, 8- and 4-16-fold higher, respectively. In RPMI-1640 micafungin and caspofungin at 1, 4, 16 and 32 mg/L as well as AMB at 2 mg/L were fungicidal against all isolates in ≤3.96, ≤4.42 and 14.96 h, respectively. In RPMI-1640 with 50% serum, caspofungin was fungicidal for all isolates only at 32 mg/L, micafungin and AMB were fungistatic. In neutropenic mice, 5 mg/kg caspofungin and 1 mg/kg AMB were ineffective against two of the three isolates. Thus, in vivo efficacy of echinocandins and AMB is weak or absent against C. krusei. Prescribers treating C. krusei infections with echinocandins should watch out for clinical resistance and therapeutic failure.

Exposure-Response Analysis of Micafungin in Neonatal Candidiasis: Pooled Analysis of Two Clinical Trials.

BACKGROUND: Neonatal candidiasis causes significant morbidity and mortality in high risk infants. The micafungin dosage regimen of 10 mg/kg established for the treatment of neonatal candidiasis is based on a laboratory animal model of neonatal hematogenous Candida meningoencephalitis and pharmacokinetic (PK)-pharmacodynamic (PD) bridging studies. However, little is known about the how these PK-PD data translate clinically. METHODS: Micafungin plasma concentrations from infants were used to construct a population PK model using Pmetrics software. Bayesian posterior estimates for infants with invasive candidiasis were used to evaluate the relationship between drug exposure and mycologic response using logistic regression. RESULTS: Sixty-four infants 3-119 days of age were included, of which 29 (45%) infants had invasive candidiasis. A 2-compartment PK model fits the data well. Allometric scaling was applied to clearance and volume normalized to the mean population weight (kg). The mean (standard deviation) estimates for clearance and volume in the central compartment were 0.07 (0.05) L/h/1.8 kg and 0.61 (0.53) L/1.8 kg, respectively. No relationship between average daily area under concentration-time curve or average daily area under concentration-time curve:minimum inhibitory concentration ratio and mycologic response was demonstrated (P > 0.05). Although not statistically significant, mycologic response was numerically higher when area under concentration-time curves were at or above the PD target. CONCLUSIONS: While a significant exposure-response relationship was not found, PK-PD experiments support higher exposures of micafungin in infants with invasive candidiasis. More patients would clarify this relationship; however, low incidence deters the feasibility of these studies.

Breakthrough Candidemia In Children On Micafungin.

We identified 8 pediatric patients on micafungin (MCFG; ≥3 doses) at our institution who had breakthrough candidemia (BC). The causative strains of the BC were Candida parapsilosis in 7 patients. The minimum inhibitory concentration of MCFG was ≤1 µg/mL (susceptible) in all 8 isolates. Immunocompromised patients may develop BC caused by MCFG-susceptible strains.

Micafungin Enhances the Human Macrophage Response to Candida albicans through ß-Glucan Exposure.

Micafungin belongs to the antifungal family of echinocandins, which act as noncompetitive inhibitors of the fungal cell wall ß-1,3-d-glucan synthase. Since Candida albicans is the most prevalent pathogenic fungus in humans, we study the involvement of micafungin in the modulation of the inflammatory response developed by human tissue macrophages against C. albicans The MIC for micafungin was 0.016 µg/ml on the C. albicans SC5314 standard strain. Micafungin induced a drastic reduction in the number of exponential SC5314 viable cells, with the fungicidal effect being dependent on the cellular metabolic activity. Notably, micafungin also caused a structural remodelling of the cell wall, leading to exposure of the ß-glucan and chitin content on the external surface. At the higher doses used (0.05 µg/ml), the antifungal also induced the blowing up of budding yeasts. In addition, preincubation with micafungin before exposure to human tissue macrophages enhanced the secretion of tumor necrosis factor alpha (TNF-α), interleukin-17A (IL-17A), and IL-10 cytokines. Our results strongly suggest that in C. albicans treatment with micafungin, in addition to having the expected toxic antifungal effect, it potentiates the immune response, improving the interaction and activation of human macrophages, probably through the unmasking of ß-glucans on the cell wall surface.

Scanning Quadrupole Data-Independent Acquisition, Part B: Application to the Analysis of the Calcineurin-Interacting Proteins during Treatment of Aspergillus fumigatus with Azole and Echinocandin Antifungal Drugs.

Calcineurin is a critical cell-signaling protein that orchestrates growth, stress response, virulence, and antifungal drug resistance in several fungal pathogens. Blocking calcineurin signaling increases the efficacy of several currently available antifungals and suppresses drug resistance. We demonstrate the application of a novel scanning quadrupole DIA method for the analysis of changes in the proteins coimmunoprecipitated with calcineurin during therapeutic antifungal drug treatments of the deadly human fungal pathogen Aspergillus fumigatus. Our experimental design afforded an assessment of the precision of the method as demonstrated by peptide- and protein-centric analysis from eight replicates of the study pool QC samples. Two distinct classes of clinically relevant antifungal drugs that are guideline recommended for the treatment of invasive "aspergillosis" caused by Aspergillus fumigatus, the azoles (voriconazole) and the echinocandins (caspofungin and micafungin), which specifically target the fungal plasma membrane and the fungal cell wall, respectively, were chosen to distinguish variations occurring in the proteins coimmunoprecipitated with calcineurin. Novel potential interactors were identified in response to the different drug treatments that are indicative of the possible role for calcineurin in regulating these effectors. Notably, treatment with voriconazole showed increased immunoprecipitation of key proteins involved in membrane ergosterol biosynthesis with calcineurin. In contrast, echinocandin (caspofungin or micafungin) treatments caused increased immunoprecipitation of proteins involved in cell-wall biosynthesis and septation. Furthermore, abundant coimmunoprecipitation of ribosomal proteins with calcineurin occurred exclusively in echinocandins treatment, indicating reprogramming of cellular growth mechanisms during different antifungal drug treatments. While variations in the observed calcineurin immunoprecipitated proteins may also be due to changes in their expression levels under different drug treatments, this study suggests an important role for calcineurin-dependent cellular mechanisms in response to antifungal treatment of A. fumigatus that warrants future studies.

Unraveling Drug Penetration of Echinocandin Antifungals at the Site of Infection in an Intra-abdominal Abscess Model.

Intra-abdominal candidiasis (IAC) is a prominent invasive fungal infection associated with high mortality. Prompt antifungal therapy and source control are crucial for successful treatment. Echinocandin antifungal drugs are first-line agents; however, their clinical effectiveness is highly variable, with known potential for breakthrough resistance, and little is known about drug exposure at the site of infection. Using matrix-assisted desorption ionization mass spectrometry imaging technology, we investigated the spatial and quantitative distribution in tissue lesions for two echinocandin drugs, micafungin and CD101, in a clinically relevant IAC mouse model. Drug accumulation within lesions was observed with both drugs at their humanized therapeutic doses. CD101, but not micafungin, accumulated in lesions at levels above the mutant prevention concentration of the infecting strain. These findings indicate that current echinocandin drugs are limited by penetration at the site of infection and have implications for clinical outcomes and emergence of resistance in patients with IAC.

Pharmacodynamic Optimization for Treatment of Invasive Candida auris Infection.

Candida auris is an emerging multidrug-resistant threat. The pharmacodynamics of three antifungal classes against nine C. auris strains was explored using a murine invasive candidiasis model. The total drug median pharmacodynamic (PD) target associated with net stasis was a fluconazole AUC/MIC (the area under the concentration-time curve over 24 h in the steady state divided by the MIC) of 26, an amphotericin B Cmax/MIC (maximum concentration of drug in serum divided by the MIC) of 0.9, and a micafungin AUC/MIC of 54. The micafungin PD targets for C. auris were ≥20-fold lower than those of other Candida species in this animal model. Clinically relevant micafungin exposures produced the most killing among the three classes.

In vitro combination therapy with isavuconazole against Candida spp.

Combination therapy may be an alternative therapeutic approach for difficult-to-treat Candida infections with the aim of increasing efficacy of antifungal therapy. Whether isavuconazole, an extended-spectrum triazole, possesses synergistic activity in combination therapy with echinocandins or polyenes for the treatment of invasive candidiasis has not been studied. We used Bliss independence drug interaction analysis and time-kill assays to examine the in vitro interactions of isavuconazole with amphotericin B or micafungin, an echinocandin, against strains of Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Candida krusei. The Bliss independence-based drug interactions modeling showed that the combination of isavuconazole and micafungin resulted in synergistic interactions against C. albicans, C. parapsilosis, and C. krusei. The degree of synergy ranged from 1.8% to 16.7% (mean %ΔΕ value) with the highest synergy occurring against C. albicans (⊙SYN% = 8.8%-110%). Time-kill assays showed that the isavuconazole-micafungin combination demonstrated concentration-depended synergy against C. albicans and C. parapsilosis. The combined interaction by Bliss analysis between isavuconazole and amphotericin B was indifferent for C. albicans, C. parapsilosis, and C. tropicalis while for C. glabrata was antagonistic (-2% to -6%) and C. krusei synergistic (3.4% to 7%). The combination of isavuconazole-amphotericin B by time-kill assay was antagonistic against C. krusei and C. glabrata. Collectively, our findings demonstrate that combinations of isavuconazole and micafungin are synergistic against Candida spp., while those of isavuconazole and amphotericin B are indifferent in vitro.

Monotherapy or combination therapy of isavuconazole and micafungin for treating murine mucormycosis.

OBJECTIVES: Previously we demonstrated the benefit of isavuconazole in treating murine mucormycosis due to Rhizopus. We wanted to determine the efficacy of isavuconazole in treating murine mucormycosis caused by Mucor, the second most common cause of the disease. Furthermore, because we previously determined that Rhizopus possesses the target enzyme for echinocandins and micafungin has activity against murine mucormycosis, we compared the activity of combination therapy (isavuconazole + micafungin) with placebo, either drug alone or standard therapy of liposomal amphotericin B (LAmB) in treating pulmonary murine mucormycosis caused by Rhizopus delemar. METHODS: In vitro susceptibility to isavuconazole of Mucorales was evaluated using the CLSI M38-A2 method. Immunosuppressed mice were intratracheally infected with either Mucor circinelloides or R. delemar. Treatment with isavuconazole (orally), micafungin (intraperitoneally), a combination of both or LAmB (intravenously) was compared, with survival and tissue fungal burden serving as primary and secondary endpoints, respectively. RESULTS: Isavuconazole was as effective as LAmB in prolonging survival of mice infected with M. circinelloides. Against R. delemar-induced mucormycosis, all monotherapy treatments significantly improved survival of mice versus placebo without showing superiority over one another. However, LAmB was superior in lowering fungal burden in target organs. Although combination therapy of isavuconazole + micafungin did not enhance survival of mice over monotherapy, antagonism was not detected between the two drugs. CONCLUSION: Isavuconazole is effective in treating pulmonary murine mucormycosis due to Mucor. In addition, combination therapy of isavuconazole + micafungin does not demonstrate synergy and it is not antagonistic against Rhizopus-induced mucormycosis.