Liposomal amphotericin B-the future.

Advances in medicine have led to a growing number of people with compromised or suppressed immune systems who are susceptible to invasive fungal infections. In particular, severe fungal infections are becoming increasingly common in ICUs, affecting people within and outside of traditional risk groups alike. This is exemplified by the emergence of severe viral pneumonia as a significant risk factor for invasive pulmonary aspergillosis, and the recognition of influenza-associated pulmonary aspergillosis and, more recently, COVID-19-associated pulmonary aspergillosis. The treatment landscape for haematological malignancies has changed considerably in recent years, and some recently introduced targeted agents, such as ibrutinib, are increasing the risk of invasive fungal infections. Consideration must also be given to the risk of drug-drug interactions between mould-active azoles and small-molecule kinase inhibitors. At the same time, infections caused by rare moulds and yeasts are increasing, and diagnosis continues to be challenging. There is growing concern about azole resistance among both moulds and yeasts, mandating continuous surveillance and personalized treatment strategies. It is anticipated that the epidemiology of fungal infections will continue to change and that new populations will be at risk. Early diagnosis and appropriate treatment remain the most important predictors of survival, and broad-spectrum antifungal agents will become increasingly important. Liposomal amphotericin B will remain an essential therapeutic agent in the armamentarium needed to manage future challenges, given its broad antifungal spectrum, low level of acquired resistance and limited potential for drug-drug interactions.

Regional Differences in Antifungal Susceptibility of the Prevalent Dermatophyte Trichophyton rubrum.

In vitro susceptibility testing for Trichophyton rubrum has shown resistance to terbinafine, azoles and amorolfine, locally, but epidemiological cutoffs are not available. In order to assess the appropriateness of current first-line antifungal treatment for T. rubrum in China, we characterized antifungal susceptibility patterns of Chinese T. rubrum strains to nine antifungals and also described the upper limits of wild-type (WT) minimal inhibitory concentrations (MIC) (UL-WT) based on our study and another six studies published during the last decades. Sixty-two clinical isolates originating from seven provinces in China were identified as T. rubrum sensu stricto; all Chinese strains showed low MICs to eight out of nine antifungal drugs. Terbinafine (TBF) showed the lowest MICs of all antifungal classes tested in both the Chinese and global groups, with a 97.5% UL-WT MIC-value of 0.03 mg/L. No non-WT isolates were observed for TBF in China, but were reported in 18.5% of the global group. Our study indicated that TBF was still the most active drug for Chinese T. rubrum isolates, and all strains were within the WT-population. TBF therefore remains recommended for primary therapy to dermatophytosis caused by T. rubrum in China now, but regular surveillance of dermatophytes and antifungal susceptibility is recommended.

In vitro interaction of isavuconazole and anidulafungin against azole-susceptible and azole-resistant Aspergillus fumigatus isolates.

BACKGROUND: The voriconazole and echinocandin combination has been found to be synergistic in vitro and in vivo against most Aspergillus fumigatus isolates, both with a WT azole phenotype and an azole-resistant phenotype. The interaction between isavuconazole and echinocandins is less well studied. This is especially true for azole-resistant isolates. OBJECTIVES: We investigated the in vitro interaction between isavuconazole and anidulafungin for 30 A. fumigatus isolates including 18 azole-resistant isolates with various isavuconazole resistance phenotypes. METHODS: The isavuconazole/anidulafungin interaction was studied by using an adapted EUCAST-based 2D (12 × 8) chequerboard broth microdilution colorimetric assay using XTT. The interaction was analysed by FIC index (FICi) analysis and Bliss independence (BI) interaction analysis. RESULTS: Both the FICi analysis and the BI analysis showed synergistic interaction between isavuconazole and anidulafungin for the majority of WT and azole-resistant isolates. As we did not see significant beneficial effects of combination therapy in TR46/Y121F/T289A isolates at clinically achievable drug concentrations, it is unlikely that TR46/Y121F/T289A infections would benefit from isavuconazole and anidulafungin combination therapy. CONCLUSIONS: In regions with high azole resistance rates this combination may benefit patients with WT disease, azole-resistant invasive aspergillosis and those with mixed azole-susceptible and azole-resistant infection, but may not be beneficial for aspergillosis due to isolates with high isavuconazole resistance, such as TR46/Y121F/T289A isolates.

Clinical relevance of Scedosporium spp. and Exophiala dermatitidis in patients with cystic fibrosis: A nationwide study.

An increased prevalence of various filamentous fungi in sputum samples of patients with cystic fibrosis (CF) has been reported. The clinical significance, however, is mostly unclear. The aim of this study was to investigate the clinical relevance of Scedosporium spp. and Exophiala dermatitidis from sputum samples of patients with CF in the Netherlands. In this cross-sectional study, all CF patients of the Dutch national CF registry who were treated at five of the seven recognized CF centers during a 3-year period were included. We linked clinical data of the national CF registry with the national Dutch filamentous fungal database. We investigated the association between clinical characteristics and a positive sputum sample for Scedosporium spp. and E. dermatitidis, using logistic regression. Positive cultures for fungi were obtained from 3787 sputum samples from 699 of the 1312 patients with CF. Scedosporium spp. was associated with severe genotype, CF-related diabetes, several microorganisms, and inhaled antibiotics. E. dermatitidis was associated with older age, female sex, and Aspergillus spp. CF patients with and without Scedosporium spp. or E. dermatitidis seemed comparable in body mass index and lung function. This study suggests that Scedosporium spp. and E. dermatitidis are probably no major pathogens in CF patients in the Netherlands. Greater understanding of epidemiologic trends, risk factors, and pathogenicity of filamentous fungi in the respiratory tracts of patients with CF is needed.

Intraspecific Diversity and Taxonomy of Emmonsia crescens.

Emmonsia crescens is known as an environmental pathogen causing adiaspiromycosis in small rodents. As the generic name Emmonsia is no longer available for this species, its taxonomic position is re-evaluated. The intraspecific variation of Emmonsia crescens was analyzed using molecular, morphological, and physiological data, and the relationship between frequency of adiaspiromycosis and body temperature of host animals was explored. A North American and a pan-global lineage could be discerned, each with subclusters at low genetic distance. European strains produced the classical type of very large adiaspores, while in the North American lineage adiaspores relatively small, resembling the broad-based budding cells of Blastomyces. Members of the closely related genus Emergomyces may exhibit large, broad-based in addition to small, narrow-based budding cells. We conclude that the morphology of the pathogenic phase in these fungi differs gradationally between species and even populations, and is therefore less suitable as a diagnostic criterion for generic delimitation. Two Emmonsia species are reclassified in Emergomyces.

Facilitators of adaptation and antifungal resistance mechanisms in clinically relevant fungi.

Opportunistic fungal pathogens can cause a diverse range of diseases in humans. The increasing rate of fungal infections caused by strains that are resistant to commonly used antifungals results in difficulty to treat diseases, with accompanying high mortality rates. Existing and newly emerging molecular resistance mechanisms rapidly spread in fungal populations and need to be monitored. Fungi exhibit a diversity of mechanisms to maintain physiological resilience and create genetic variation; processes which eventually lead to the selection and spread of resistant fungal pathogens. To prevent and anticipate this dispersion, the role of evolutionary factors that drive fungal adaptation should be investigated. In this review, we provide an overview of resistance mechanisms against commonly used antifungal compounds in the clinic and for which fungal resistance has been reported. Furthermore, we aim to summarize and elucidate potent generators of genetic variability across the fungal kingdom that aid adaptation to stressful environments. This knowledge can lead to recognizing potential niches that facilitate fast resistance development and can provide leads for new management strategies to battle the emerging resistant populations in the clinic and the environment.

Diagnostic-driven management of invasive fungal disease in hematology in the era of prophylaxis and resistance emergence: Dutch courage?

Patients receiving intensive anti-leukemic treatment or recipients of allogeneic hematopoietic stem cell transplantation (HSCT) are prone to develop invasive fungal disease caused by both Aspergillus and non-Aspergillus moulds. Overall mortality following invasive mould disease (IMD) is high; adequate and timely antifungal treatment seems to ameliorate the outcome, yet early diagnosis in the haematological patient remains a challenge for most clinicians. Prophylaxis and the empiric addition of antifungal therapy to neutropaenic patients with fever persisting or recurring during broad-spectrum antibiotic treatment is therefore standard of care in many institutions. However, aside from the potential for overtreatment and important side effects, the emergence of resistance to medical triazoles in Aspergillus fumigatus poses a risk for inadequate initial treatment. Initial voriconazole therapy in patients with azole-resistant invasive aspergillosis was recently shown to be associated with a 23% increased mortality rate compared to the patients with azole-susceptible infection, despite changing to appropriate antifungal therapy once resistance was detected. Moreover, fever is not always present with IMD; therefore, cases may be missed when relying solely on this symptom for starting diagnostic procedures and antifungal treatment. At our institution, a diagnostic-driven treatment approach for IMD was implemented relying on clinical but also laboratory markers to start antifungal treatment. We describe the basis and clinical implementation of our diagnostic-driven approach in this review.

Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis.

Our in vitro studies showed that a combination of amphotericin B and terbinafine had synergistic effects against the majority of melanized fungi associated with chromoblastomycosis (CBM) and similar infections, including those with Cladophialophora carrionii, Cladophialophora arxii, Exophialadermatitidis, Exophialaspinifera, Fonsecaea monophora, Fonsecaea nubica, Fonsecaea pedrosoi, and Phialophora verrucosa. This drug combination could provide an option for the treatment of severe or unresponsive cases of CBM, particularly in cases due to species of Fonsecaea and Cladophialophora.

Epidemiology of invasive aspergillosis and triazole-resistant Aspergillus fumigatus in patients with haematological malignancies: a single-centre retrospective cohort study.

Objectives: To investigate the epidemiology and clinical relevance of triazole resistance among patients undergoing treatment for haematological malignancies who are at risk of invasive aspergillosis (IA). Methods: This was a retrospective cohort study for which the records of consecutive patients given chemotherapy for AML or myelodysplastic syndrome (MDS) or who had received an allogeneic HSCT from 2006 to 2012 were reviewed for IA. Triazole resistance was detected by the VIPcheck™ screening method and confirmed by determining the MIC by EUCAST methodology. Results: A total of 432 patients were included, comprising 182 (42.1%) patients who had undergone chemotherapy for AML or MDS, and 250 (57.9%) patients who had undergone an allogeneic HSCT. Probable or proven IA was diagnosed in 36 cases (8.3%, 95% CI 6.0%-11.4%). Of these, 12 (33.3%) were based on recovery of Aspergillus fumigatus from sputum, bronchoalveolar lavage or biopsy, and triazole resistance was found in 2 instances. A. fumigatus was also recovered from one or more specimens from 13 patients without probable or proven IA. Triazole resistance was documented for three patients. The survival rate of patients with IA caused by voriconazole-resistant isolates could not be assessed. Conclusions: The overall frequency of voriconazole-resistant IA among patients at high risk was low. However, the rate of triazole resistance may have been underestimated by the low detection rate based on recovery of A. fumigatus. Alternative diagnostic tests, such as PCR-based assays, may prove better at detecting IA due to triazole-resistant A. fumigatus.

Single-Center Evaluation of an Agar-Based Screening for Azole Resistance in Aspergillus fumigatus by Using VIPcheck.

Antifungal susceptibility testing is an essential tool for guiding therapy, although EUCAST and CLSI reference methods are often available only in specialized centers. We studied the performance of an agar-based screening method for the detection of azole resistance in Aspergillus fumigatus cultures. The VIPcheck consists of four wells containing voriconazole, itraconazole, posaconazole, or a growth control. Ninety-six A. fumigatus isolates were used. Thirty-three isolates harbored a known resistance mechanism: TR34/L98H (11 isolates), TR46/Y121F/T289A (6 isolates), TR53 (2 isolates), and 14 isolates with other cyp51A gene point mutations. Eighteen resistant isolates had no cyp51A-mediated azole resistance. Forty-five isolates had a wild-type (WT) azole phenotype. Four technicians and two inexperienced interns, blinded to the genotype/phenotype, read the plates visually after 24 h and 48 h and documented minimal growth, uninhibited growth, and no growth. The performance was compared to the EUCAST method. After 24 h of incubation, the mean sensitivity and specificity were 0.54 and 1.00, respectively, with uninhibited growth as the threshold. After 48 h of incubation, the performance mean sensitivity and specificity were 0.98 and 0.93, respectively, with minimal growth. The performance was not affected by observer experience in mycology. The interclass correlation coefficient was 0.87 after 24 h and 0.85 after 48 h. VIPcheck enabled the selection of azole-resistant A. fumigatus colonies, with a mean sensitivity and specificity of 0.98 and 0.93, respectively. Uninhibited growth on any azole-containing well after 24 h and minimal growth after 48 h were indicative of resistance. These results indicate that the VIPcheck is an easy-to-use tool for azole resistance screening and the selection of colonies that require MIC testing.

In vitro activity of the novel antifungal compound F901318 against difficult-to-treat Aspergillus isolates.

Background: F901318 is a new antifungal agent with a novel mechanism of action with activity against Aspergillus species. We investigated the in vitro activity of F901318 against a collection of Aspergillus isolates. Methods: A total of 213 Aspergillus isolates were used in this study. A total of 143 Aspergillus fumigatus sensu stricto isolates were used, of which 133 were azole resistant [25 TR34/L98H; 25 TR46/Y121F/T289A; 33 A. fumigatus with cyp51A-associated point mutations (25 G54, 1 G432 and 7 M220); and 50 azole-resistant A. fumigatus without known resistance mechanisms]. Ten azole-susceptible A. fumigatus isolates were used as WT controls. The in vitro activity was also determined against Aspergillus calidoustus (25 isolates), Aspergillus flavus (10), Aspergillus nidulans (10) and Aspergillus tubingensis (25). F901318 activity was compared with that of itraconazole, voriconazole, posaconazole, isavuconazole, amphotericin B and anidulafungin. Minimum effective concentrations and MICs were determined using the EUCAST broth microdilution method. Results: F901318 was active against all tested isolates: A. fumigatus WT, MIC90 0.125 mg/L (range 0.031-0.125); TR34/L98H,TR46/Y121F/T289A and azole resistant without known resistance mechanisms, MIC90 0.125 mg/L (range 0.031-0.25); A. fumigatus with cyp51A-associated point mutations, MIC90 0.062 mg/L (range 0.015-0.125); and other species, A. calidoustus MIC90 0.5 mg/L (range 0.125-0.5), A. flavus MIC90 0.062 mg/L (range 0.015-0.62), A. nidulans MIC90 0.125 mg/L (range 0.062-0.25) and A. tubingensis MIC90 0.062 mg/L (range 0.015-0.25). Conclusions: F901318 showed potent and consistent in vitro activity against difficult-to-treat Aspergillus spp. with intrinsic and acquired antifungal resistance due to known and unknown resistance mechanisms, suggesting no significant implications of azole resistance mechanisms for the mode of action of F901318.

Combination of Amphotericin B and Flucytosine against Neurotropic Species of Melanized Fungi Causing Primary Cerebral Phaeohyphomycosis.

Primary central nervous system phaeohyphomycosis is a fatal fungal infection due mainly to the neurotropic melanized fungiCladophialophora bantiana,Rhinocladiella mackenziei, andExophiala dermatitidis.Despite the combination of surgery with antifungal treatment, the prognosis continues to be poor, with mortality rates ranging from 50 to 70%. Therefore, a search for a more-appropriate therapeutic approach is urgently needed. Ourin vitrostudies showed that with the combination of amphotericin B and flucytosine against these species, the median fractional inhibitory concentration (FIC) indices for strains ranged from 0.25 to 0.38, indicating synergy. By use of Bliss independence analysis, a significant degree of synergy was confirmed for all strains, with the sum ΔE ranging from 90.2 to 698.61%. No antagonism was observed. These results indicate that amphotericin B, in combination with flucytosine, may have a role in the treatment of primary cerebral infections caused by melanized fungi belonging to the orderChaetothyriales Furtherin vivostudies and clinical investigations to elucidate and confirm these observations are warranted.

Prospective multicenter international surveillance of azole resistance in Aspergillus fumigatus.

To investigate azole resistance in clinical Aspergillus isolates, we conducted prospective multicenter international surveillance. A total of 3,788 Aspergillus isolates were screened in 22 centers from 19 countries. Azole-resistant A. fumigatus was more frequently found (3.2% prevalence) than previously acknowledged, causing resistant invasive and noninvasive aspergillosis and severely compromising clinical use of azoles.

In vitro antifungal susceptibility of Trichophyton violaceum isolated from tinea capitis patients.

OBJECTIVES: Trichophyton violaceum is an anthropophilic dermatophyte that is endemic to parts of Africa and Asia and is sporadic in Europe. T. violaceum mainly causes tinea capitis in both children and adolescents. Although the infections caused by T. violaceum are of considerable medical importance, its antifungal susceptibility profile remains poorly examined. METHODS: In this study, we tested the in vitro antifungal susceptibility of a set of clinical T. violaceum isolates obtained from tinea capitis patients, using the CLSI broth microdilution method. We tested eight antifungals and used isolates collected from Western China (21), Eastern China (12), the Middle East (1), Europe (20), South Africa (7) and Canada (1). RESULTS: The geometric means of the MICs of the antifungals for all isolates were as follows (in increasing order): posaconazole, 0.021 mg/L; terbinafine, 0.023 mg/L; voriconazole, 0.062 mg/L; amphotericin B, 0.20 mg/L; itraconazole, 0.34 mg/L; caspofungin, 0.56 mg/L; fluconazole, 4.23 mg/L; and flucytosine, 8.46 mg/L. No statistically significant differences in the susceptibility profiles of T. violaceum were detected within the geographical regions tested. CONCLUSIONS: Posaconazole, terbinafine and voriconazole were shown to be the most potent antifungal agents against T. violaceum isolates obtained from tinea capitis patients worldwide. These results might help clinicians in developing appropriate therapies that have a high probability of successfully treating tinea capitis due to T. violaceum.

Emergence of fusarioses in a university hospital in Turkey during a 20-year period.

Fusarium species have started appearing increasingly as the main cause of infections, particularly in immunocompromised patients. In this study, we aimed to present the first epidemiological data from Turkey, analyze fusariosis cases that have been monitored in a university hospital during the past 20 years, identify the responsible Fusarium species, and determine antifungal susceptibilities. A total of 47 cases of fusariosis was included in the study. Fusarium isolates were identified by multilocus sequence typing (MLST). Antifungal susceptibility was tested by the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) methodology. Of the Fusarium infections, 23.4 % were superficial, 44.7 % were locally invasive, and 31.9 % were disseminated. A significant increase was observed over the years. The Fusarium fujikuroi species complex (FFSC) proved to be the most frequent agent group (17 cases; 51.5 %), followed by the Fusarium solani species complex (FSSC) (14 cases; 42.4 %), the Fusarium dimerum species complex (FDSC), and the Fusarium oxysporum species complexes (FOSC) (one case each). Amphotericin B had the highest in vitro activity against all species. Voriconazole and posaconazole showed interspecies variability across and within Fusarium species complexes. In conclusion, our data support the fact that regional differences exist in the distribution of the Fusarium species and that species-specific differences are observed in antifungal susceptibility patterns. The monitoring of local epidemiological data by determining fungal identity and susceptibility are of importance in guiding the clinical follow-up of patients.

Susceptibility breakpoints for amphotericin B and Aspergillus species in an in vitro pharmacokinetic-pharmacodynamic model simulating free-drug concentrations in human serum.

Although conventional amphotericin B was for many years the drug of choice and remains an important agent against invasive aspergillosis, reliable susceptibility breakpoints are lacking. Three clinical Aspergillus isolates (Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus) were tested in an in vitro pharmacokinetic-pharmacodynamic model simulating the biphasic 24-h time-concentration profile of free amphotericin B concentrations in human serum with free peak concentrations (fCmax) of 0.1, 0.3, 0.6, 1.2, and 2.4 mg/liter administered once daily. Drug concentrations were measured with a bioassay, and fungal growth was monitored for 72 h with galactomannan production. The fCmax/MIC corresponding to half-maximal activity (P50) was determined for each species, and the percentage of target attainment was calculated for different MICs for the standard (1 mg/kg of body weight) and a lower (0.6-mg/kg) dose of amphotericin B with Monte Carlo simulation analysis. The fCmax/MICs (95% confidence intervals) corresponding to P50 were 0.145 (0.133 to 0.158), 0.371 (0.283 to 0.486), and 0.41 (0.292 to 0.522) for A. fumigatus, A. flavus, and A. terreus, respectively. The median percentages of P50 attainment were ≥88%, 47%, and 0% for A. fumigatus isolates with MICs of ≤0.5, 1, and ≥2 mg/liter, respectively, and ≥81%, 24%, and 0% and ≥75%, 15%, and 0% for A. flavus and A. terreus isolates with MICs of ≤0.25, 0.5, and ≥1 mg/liter, respectively. The lower dose of 0.6 mg/kg would retain efficacy for A. fumigatus, A. flavus, and A. terreus isolates with MICs of ≤0.25, ≤0.125, and ≤0.125 mg/liter, respectively. The susceptibility, intermediate susceptibility, and resistance breakpoints of ≤0.5, 1, and ≥2 mg/liter for A. fumigatus and ≤0.25, 0.5, and ≥1 mg/liter for A. flavus and A. terreus were determined for conventional amphotericin B with a pharmacokinetic-pharmacodynamic model simulating free-drug serum concentrations.

Antifungal susceptibility patterns of opportunistic fungi in the genera Verruconis and Ochroconis.

Species of Verruconis and species of Ochroconis are dematiaceous fungi generally found in the environment but having the ability to infect humans, dogs, cats, poultry, and fish. This study presents the antifungal susceptibility patterns of these fungi at the species level. Forty strains originating from clinical and environmental sources were phylogenetically identified at the species level by using sequences of the ribosomal DNA internal transcribed spacer (rDNA ITS). In vitro antifungal susceptibility testing was performed against eight antifungals, using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. The geometric mean MICs for amphotericin B (AMB), flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), and posaconazole (POS) and minimum effective concentrations (MECs) for caspofungin (CAS) and anidulafungin (AFG) across the Ochroconis and Verruconis species were as follows, in increasing order. For Verruconis species, the values (µg/ml) were as follows: AFG, 0.04; POS, 0.25; ITC, 0.37; AMB, 0.50; CAS, 0.65; VRC, 0.96; 5FC, 10.45; and FLC, 47.25. For Ochroconis species, the values (µg/ml) were as follows: AFG, 0.06; POS, 0.11; CAS, 0.67; VRC, 2.76; ITC, 3.94; AMB, 5.68; 5FC, 34.48; and FLC, 61.33. Antifungal susceptibility of Ochroconis and Verruconis was linked with phylogenetic distance and thermotolerance. Echinocandins and POS showed the greatest in vitro activity, providing possible treatment options for Ochroconis and Verruconis infections.

Pharmacokinetics of caspofungin in ICU patients.

OBJECTIVES: Caspofungin is used for treatment of invasive fungal infections. As the pharmacokinetics (PK) of antimicrobial agents in critically ill patients can be highly variable, we set out to explore caspofungin PK in ICU patients. METHODS: ICU patients receiving caspofungin were eligible. Patients received a loading dose of 70 mg followed by 50 mg daily (70 mg if body weight >80 kg); they were evaluable upon completion of the first PK curve at day 3. Additionally, daily trough samples were taken and a second PK curve was recorded at day 7. PK analysis was performed using a standard two-stage approach. RESULTS: Twenty-one patients were evaluable. Median (range) age and body weight were 71 (45-80) years and 75 (50-99) kg. PK sampling on day 3 (n = 21) resulted in the following median (IQR) parameters: AUC0-24 88.7 (72.2-97.5) mg·h/L; Cmin 2.15 (1.40-2.48) mg/L; Cmax 7.51 (6.05-8.17) mg/L; V 7.72 (6.12-9.01) L; and CL 0.57 (0.54-0.77) L/h. PK sampling on day 7 (n = 13) resulted in AUC0-24 107.2 (90.4-125.3) mg·h/L, Cmin 2.55 (1.82-3.08) mg/L, Cmax 8.65 (7.16-9.34) mg/L, V 7.03 (5.51-7.73) L and CL 0.54 (0.44-0.60) L/h. We did not identify any covariates significantly affecting caspofungin PK in ICU patients (e.g. body weight, albumin, liver function). Caspofungin was well tolerated and no unexpected side effects were observed. CONCLUSIONS: Caspofungin PK in ICU patients showed limited intraindividual and moderate interindividual variability, and caspofungin was well tolerated. A standard two-stage approach did not reveal significant covariates. Our study showed similar caspofungin PK parameters in ICU patients compared with non-critically ill patients.

Absence of COVID-19 associated mucormycosis in a tertiary intensive care unit in the Netherlands.

Mucormycosis is a severe complication in critically ill COVID-19 patients. Throughout the pandemic, a notable prevalence of mucormycosis has been observed in the Indian population, whereas lower occurrences have been reported in Europe. However, limited data exist regarding its prevalence in Europe, which is potentially underestimated due to the low sensitivity of bronchoalveolar lavage (BAL) cultures. We aimed to evaluate the prevalence of mucormycosis in a high-risk critically ill COVID-19 population in the Netherlands, and to evaluate the potential benefit of adding Mucor PCR to BAL as part of routine follow-up. In this study, we included 1035 critically ill COVID-19 patients admitted to either one of the two ICUs at AmsterdamUMC between March 2020 and May 2022; of these, 374 had undergone at least one bronchoscopy. Following the AmsterdamUMC protocols, bronchoscopies were conducted weekly until clinical improvement was achieved. We cultured BAL fluid for fungi and used PCR and galactomannan testing to detect Aspergillus spp. Additionally, we retrospectively performed qPCR targeting Mucorales DNA in the BAL of 89 deceased patients. All cultures were negative for Mucorales, whereas 42 (11%) cultures were positive for Aspergillus. Furthermore, qPCR targeting Mucorales was negative in all 89 deceased patients. This study showed that pulmonary mucormycosis was not present in critically ill COVID-19 patients in two tertiary care ICUs. These results indicate routine Mucorales qPCR screening is not clinically necessary in a high-standard-of-care tertiary ICU in a low-endemic area.

Epidemiological cutoff values for azoles and Aspergillus fumigatus based on a novel mathematical approach incorporating cyp51A sequence analysis.

Epidemiological cutoff values (ECV) are commonly used to separate wild-type isolates from isolates with reduced susceptibility to antifungal drugs, thus setting the foundation for establishing clinical breakpoints for Aspergillus fumigatus. However, ECVs are usually determined by eye, a method which lacks objectivity, sensitivity, and statistical robustness and may be difficult, in particular, for extended and complex MIC distributions. We therefore describe and evaluate a statistical method of MIC distribution analysis for posaconazole, itraconazole, and voriconazole for 296 A. fumigatus isolates utilizing nonlinear regression analysis, the normal plot technique, and recursive partitioning analysis incorporating cyp51A sequence data. MICs were determined by using the CLSI M38-A2 protocol (CLSI, CLSI document M38-A2, 2008) after incubation of the isolates for 48 h and were transformed into log(2) MICs. We found a wide distribution of MICs of all azoles, some ranging from 0.02 to 128 mg/liter, with median MICs of 32 mg/liter for itraconazole, 4 mg/liter for voriconazole, and 0.5 mg/liter for posaconazole. Of the isolates, 65% (192 of 296) had mutations in the cyp51A gene, and the majority of the mutants (90%) harbored tandem repeats in the promoter region combined with mutations in the cyp51A coding region. MIC distributions deviated significantly from normal distribution (D'Agostino-Pearson omnibus normality test P value, <0.001), and they were better described with a model of the sum of two Gaussian distributions (R(2), 0.91 to 0.96). The normal plot technique revealed a mixture of two populations of MICs separated by MICs of 1 mg/liter for itraconazole, 1 mg/liter for voriconazole, and 0.125 mg/liter for posaconazole. Recursive partitioning analysis confirmed these ECVs, since the proportions of isolates harboring cyp51A mutations associated with azole resistance were less than 20%, 20 to 30%, and >70% when the MICs were lower than, equal to, and higher than the above-mentioned ECVs, respectively.