Precise genome editing underlines the distinct contributions of mutations in ERG11, ERG3, MRR1, and TAC1 genes to antifungal resistance in Candida parapsilosis.

Candida parapsilosis has recently emerged as a major threat due to the worldwide emergence of fluconazole-resistant strains causing clonal outbreaks in hospitals and poses a therapeutic challenge due to the limited antifungal armamentarium. Here, we used precise genome editing using CRISPR-Cas9 to gain further insights into the contribution of mutations in ERG11, ERG3, MRR1, and TAC1 genes and the influence of allelic dosage to antifungal resistance in C. parapsilosis. Seven of the most common amino acid substitutions previously reported in fluconazole-resistant clinical isolates (including Y132F in ERG11) were engineered in two fluconazole-susceptible C. parapsilosis lineages (ATCC 22019 and STZ5). Each mutant was then challenged in vitro against a large array of antifungals, with a focus on azoles. Any possible change in virulence was also assessed in a Galleria mellonella model. We successfully generated a total of 19 different mutants, using CRISPR-Cas9. Except for R398I (ERG11), all remaining amino acid substitutions conferred reduced susceptibility to fluconazole. However, the impact on fluconazole in vitro susceptibility varied greatly according to the engineered mutation, the stronger impact being noted for G583R acting as a gain-of-function mutation in MRR1. Cross-resistance with newer azoles, non-medical azoles, but also non-azole antifungals such as flucytosine, was occasionally noted. Posaconazole and isavuconazole remained the most active in vitro. Except for G583R, no fitness cost was associated with the acquisition of fluconazole resistance. We highlight the distinct contributions of amino acid substitutions in ERG11, ERG3, MRR1, and TAC1 genes to antifungal resistance in C. parapsilosis.

Is the C-Terminal Domain an Effective and Selective Target for the Design of Hsp90 Inhibitors against Candida Yeast?

Improving the armamentarium to treat invasive candidiasis has become necessary to overcome drug resistance and the lack of alternative therapy. In the pathogenic fungus Candida albicans, the 90-kDa Heat-Shock Protein (Hsp90) has been described as a major regulator of virulence and resistance, offering a promising target. Some human Hsp90 inhibitors have shown activity against Candida spp. in vitro, but host toxicity has limited their use as antifungal drugs. The conservation of Hsp90 across all species leads to selectivity issues. To assess the potential of Hsp90 as a druggable antifungal target, the activity of nine structurally unrelated Hsp90 inhibitors with different binding domains was evaluated against a panel of Candida clinical isolates. The Hsp90 sequences from human and yeast species were aligned. Despite the degree of similarity between human and yeast N-terminal domain residues, the in vitro activities measured for the inhibitors interacting with this domain were not reproducible against all Candida species. Moreover, the inhibitors binding to the C-terminal domain (CTD) did not show any antifungal activity, with the exception of one of them. Given the greater sequence divergence in this domain, the identification of selective CTD inhibitors of fungal Hsp90 could be a promising strategy for the development of innovative antifungal drugs.

Discovery of New Broad-Spectrum Anti-Infectives for Eukaryotic Pathogens Using Bioorganometallic Chemistry.

Drug resistance observed with many anti-infectives clearly highlights the need for new broad-spectrum agents to treat especially neglected tropical diseases (NTDs) caused by eukaryotic parasitic pathogens, including fungal infections. Herein, we show that the simple modification of one of the most well-known antifungal drugs, fluconazole, with organometallic moieties not only improves the activity of the parent drug but also broadens the scope of application of the new derivatives. These compounds were highly effective in vivo against pathogenic fungal infections and potent against parasitic worms such as Brugia, which causes lymphatic filariasis and Trichuris, one of the soil-transmitted helminths that infects millions of people globally. Notably, the identified molecular targets indicate a mechanism of action that differs greatly from that of the parental antifungal drug, including targets involved in biosynthetic pathways that are absent in humans, offering great potential to expand our armamentarium against drug-resistant fungal infections and neglected tropical diseases (NTDs) targeted for elimination by 2030.

Antifungal efficacy of imidazo[1,2-a]pyrazine-based thiosemicarbazones and thiazolidinediones against Sporothrix species.

Aim: To evaluate antifungal potential of 5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine hybrids based on thiosemicarbazones and thiazolidinediones against pathogenic Sporothrix species. Methods: Antifungal activity of nine compounds were assessed by broth microdilution. Interactions between active compounds and itraconazole were evaluated by the checkerboard assay using non-wild-type isolates. Cytotoxicity of the compounds was determined. Results: Four C-3 substituted analogs showed antifungal activity, unrelated to thiosemicarbazone or thiazolidinedione functions. Synergistic interactions between the four compounds and itraconazole, and low toxicity on mouse fibroblast cells were observed. Activity of 5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine hybrids against Sporothrix depended on the substitution on the imidazopyrazine ring. Conclusion: Antifungal potential, overcoming itraconazole resistance and low toxicity indicate the possible use of that series of compounds in a therapeutic alternative for treatment of sporotrichosis.

The Mortality Attributable to Candidemia in C. auris Is Higher than That in Other Candida Species: Myth or Reality?

Candida auris has become a major health threat due to its transmissibility, multidrug resistance and severe outcomes. In a case-control design, 74 hospitalised patients with candidemia were enrolled. In total, 22 cases (29.7%) and 52 controls (C. albicans, 21.6%; C. parapsilosis, 21.6%; C. tropicalis, 21.6%; C. glabrata, 1.4%) were included and analysed in this study. Risk factors, clinical and microbiological characteristics and outcomes of patients with C. auris and non-auris Candida species (NACS) candidemia were compared. Previous fluconazole exposure was significantly higher in C. auris candidemia patients (OR 3.3; 1.15-9.5). Most C. auris isolates were resistant to fluconazole (86.3%) and amphotericin B (59%) whilst NACS isolates were generally susceptible. No isolates resistant to echinocandins were detected. The average time to start antifungal therapy was 3.6 days. Sixty-three (85.1%) patients received adequate antifungal therapy, without significant differences between the two groups. The crude mortality at 30 and 90 days of candidemia was up to 37.8% and 40.5%, respectively. However, there was no difference in mortality both at 30 and 90 days between the group with candidemia by C. auris (31.8%) and by NACS (42.3%) (OR 0.6; 95% IC 0.24-1.97) and 36.4% and 42.3% (0.77; 0.27-2.1), respectively. In this study, mortality due to candidemia between C. auris and NACS was similar. Appropriate antifungal therapy in both groups may have contributed to finding no differences in outcomes.

Acquired fluconazole resistance and genetic clustering in Diutina (Candida) catenulata from clinical samples.

OBJECTIVES: Diutina (Candida) catenulata is an ascomycetous yeast isolated from environmental sources and animals, occasionally infecting humans. The aim of this study is to shed light on the in vitro antifungal susceptibility and genetic diversity of this opportunistic yeast. METHODS: Forty-five D. catenulata strains isolated from various sources (including human and environmental sources) and originating from nine countries were included. Species identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed via internal transcribed spacer ribosomal DNA barcoding. In vitro antifungal susceptibility was determined for seven systemic antifungals via the gradient strip method after 48 hours of incubation at 35°C using Etest® (Biomérieux) or Liofilchem® strips. Isolates exhibiting fluconazole minimal inhibitory concentrations (MICs) of ≥8 µg/mL were investigated for mutations in the ERG11 gene. A novel microsatellite genotyping scheme consisting of four markers was developed to assess genetic diversity. RESULTS: MIC ranges for amphotericin B, caspofungin, micafungin, isavuconazole, and posaconazole were 0.19-1 µg/mL, 0.094-0.5 µg/mL, 0.012-0.064 µg/mL, 0.003-0.047 µg/mL, and 0.006-0.032 µg/mL, respectively. By comparison, a broad range of MICs was noted for fluconazole (0.75 to >256 µg/mL) and voriconazole (0.012-0.38 mg/L), the higher values being observed among clinical strains. The Y132F amino acid substitution, associated with azole resistance in various Candida species (C. albicans, C. tropicalis, C. parapsilosis, and C. orthopsilosis), was the main substitution identified. Although microsatellite typing showed extensive genetic diversity, most strains with high fluconazole MICs clustered together, suggesting human-to-human transmission or a common source of contamination. DISCUSSION: The high rate of acquired fluconazole resistance among clinical isolates of D. catenulata is of concern. In this study, we highlight a link between the genetic diversity of D. catenulata and its antifungal resistance patterns, suggesting possible clonal transmission of resistant isolates.

The Novodiag® Stool parasites assay, an innovative high-plex technique for fast detection of protozoa, helminths and microsporidia in stool samples: a retrospective and prospective study.

OBJECTIVES: We provide the first evaluation of the CE-IVD marked Novodiag® stool parasites assay (NVD), allowing rapid and high-plex detection of 26 distinct targets, encompassing protozoans, helminths and microsporidia in stool samples. METHODS: A total of 254 samples (n = 205 patients) were prospectively processed by the NVD and our routine procedure (RP). Performances of the NVD were compared with RP. Samples only positive by the NVD assay were investigated by external PCR assays. Sensitivity and specificity (Se/Sp) and time from sample receipt to results were determined for each method. The NVD was also evaluated against 77 additional samples positive for a wide range of parasites. RESULTS: Overall positivity rate was 16.9% for RP compared with 34% using the NVD assay, and 164 samples (66%) were negative by both methods. Only 30 positive samples (12%) showed full concordance between RP and NVD. Fifty-three discordant samples were sent for external investigations. Except for Giardia intestinalis and Trichuris spp., higher Se was observed for the NVD assay for Blastocystis spp. (100% vs. 63%), Dientamoeba fragilis (100% vs. 0%), Schistosoma spp. (100% vs. 17%), and Enterobius vermicularis (100% vs. 67%) but roughly similar to RP for the remaining parasites tested. False-positive results were identified for Blastocystis spp., G. intestinalis, and Trichuris spp. using the NVD assay. The NVD mostly provides a diagnosis on the day of sample receipt compared with a mean of three days with RP. CONCLUSIONS: Besides some limitations, the NVD is a new diagnostic strategy allowing rapid and high-plex detection of gastrointestinal parasites from unpreserved stools.

Title: Le test Novodiag® Stool parasites, une technique high-plex innovante pour la détection rapide des protozoaires, helminthes et microsporidies dans les échantillons de selles : une étude rétrospective et prospective. Abstract: Objectifs : Nous présentons la première évaluation du kit Novodiag® Stool parasite (NVD) marqué CE-IVD, permettant la détection rapide de 26 cibles distinctes dans les selles (protozoaires, helminthes et microsporidies). Méthodes : Un total de 254 échantillons (n = 205 patients) a été traité prospectivement par le NVD et notre procédure de routine (PR). Les performances du NVD ont été comparées à celles de la PR. Seuls les échantillons positifs au test NVD ont été étudiés par des PCR externes. La sensibilité et la spécificité (Se/Sp) ainsi que le temps écoulé entre la réception de l'échantillon et les résultats ont été déterminés pour chaque méthode. Le NVD a également été évalué par rapport à 77 échantillons supplémentaires positifs pour un large éventail de parasites. Résultats : Le taux de positivité global était de 16,9 % pour la PR contre 34 % avec le NVD, et 164 échantillons (66 %) étaient négatifs par les deux méthodes. Seuls 30 échantillons positifs (12 %) ont montré une concordance complète entre la PR et le NVD. Cinquante-trois échantillons discordants ont été envoyés pour des investigations externes. À l'exception de Giardia intestinalis et de Trichuris spp., des Se plus élevées ont été observées pour le test NVD pour Blastocystis spp. (100 % contre 63 %), Dientamoeba fragilis (100 % contre 0 %), Schistosoma spp. (100 % contre 17 %), Enterobius vermicularis (100 % contre 67 %) mais étaient à peu près similaires à la PR pour les autres parasites testés. Des faux positifs ont été identifiés pour Blastocystis spp., G. intestinalis et Trichuris spp. en utilisant le NVD. Le NVD fournit le plus souvent un diagnostic le jour de la réception du prélèvement contre une moyenne de trois jours avec la PR. Conclusions : Malgré quelques limites, le test NVD est une nouvelle stratégie de diagnostic permettant une détection rapide et high-plex des parasites gastro-intestinaux à partir de selles non conservées.

Prototheca Infections and Ecology from a One Health Perspective.

Prototheca microalgae were only recognized as pathogens of both humans and animals in the 1960s; however, since then, these microbes have been drawing increasing interest in both human and veterinary medicine. The first human outbreak of protothecosis in a tertiary care chemotherapy ward in 2018 further highlighted the need to understand in more depth and detail their ecology, etiology, pathogenesis and routes of transmission between different hosts, environments and habitats from a One Health perspective. Protothecal infections have been reported in a growing number of cattle herds around the world in recent decades, and Prototheca has become an important bovine mastitis pathogen in certain countries and regions. The survival of Prototheca in the environment and its ability to spread in the herd pose a serious challenge to the management of infected dairy farms. Prevention of the disease is particularly important, as there is no effective and reliable treatment for it and the chances of self-healing are minimal. Therefore, the development of more effective drugs is needed for the treatment of human and animal protothecosis. The prudent use of antibiotics and their replacement by alternative or preventive measures, when possible, may further contribute to the control of protothecal infections.

CRISPR-Cas9 approach confirms Calcineurin-responsive zinc finger 1 (Crz1) transcription factor as a promising therapeutic target in echinocandin-resistant Candida glabrata.

Invasive fungal infections, which kill more than 1.6 million patients each year worldwide, are difficult to treat due to the limited number of antifungal drugs (azoles, echinocandins, and polyenes) and the emergence of antifungal resistance. The transcription factor Crz1, a key regulator of cellular stress responses and virulence, is an attractive therapeutic target because this protein is absent in human cells. Here, we used a CRISPR-Cas9 approach to generate isogenic crz1Δ strains in two clinical isolates of caspofungin-resistant C. glabrata to analyze the role of this transcription factor in susceptibility to echinocandins, stress tolerance, biofilm formation, and pathogenicity in both non-vertebrate (Galleria mellonella) and vertebrate (mice) models of candidiasis. In these clinical isolates, CRZ1 disruption restores the susceptibility to echinocandins in both in vitro and in vivo models, and affects their oxidative stress response, biofilm formation, cell size, and pathogenicity. These results strongly suggest that Crz1 inhibitors may play an important role in the development of novel therapeutic agents against fungal infections considering the emergence of antifungal resistance and the low number of available antifungal drugs.

Lethal destructive sinusopathy due to amphotericin B-resistant Aspergillus flavus: A case report.

BACKGROUND: The prevalence of pulmonary aspergillosis and the importance of its early diagnosis are recognized. However, non-pulmonary involvement, including the sinuses region, is not frequently reported, and an infection in this area can affect all paranasal sinuses (pansinusopathy), being a rare pathology that affects immunocompromised hosts. Recent studies have highlighted the occurrence of Aspergillus flavus resistant to antifungal therapy. Therefore, a nasal sinus infection by resistant Aspergillus strains in immunocompromised patients may be linked to a high risk of lethality. CASE REPORT: We are reporting a resistant A. flavus infection in an allogeneic hematopoietic stem cell transplant recipient with episodes of febrile neutropenia, and prolonged use of various antibacterial drugs and antifungal prophylaxis. The patient underwent brain magnetic resonance, which showed the presence of pansinusopathy, and presented necrosis in the left nasal region. Direct microscopic examination of a sample taken from the nasal mucosa revealed the presence of septate hyphae and conidiophores resembling those of A. flavus, that species being the identification achieved with MALDI-TOF MS. Antifungigram was performed by microdilution in broth (EUCAST-E.DEF. 9.3.2) and E-test, and resistance to amphotericin B was shown in both tests. The patient died after septic shock and hemorrhage. CONCLUSIONS: Invasive fungal infections due to amphotericin-B resistant A. flavus may lead to the death of the patient due to an ineffective therapeutic management. Therefore, antifungal susceptibility testing are of utmost importance for administering the proper treatment.

Selecting a multiplex PCR panel for accurate molecular diagnosis of intestinal protists: a comparative study of Allplex® (Seegene®), G-DiaParaTrio (Diagenode®), and RIDA®GENE (R-Biopharm®) assays and microscopic examination.

Commercial multiplex PCR assay panels were developed to overcome the limitations of microscopic examination for parasitological diagnosis on stool samples. However, given the increased supply of this diagnostic approach, these assays must be evaluated to position them in a diagnostic algorithm. Analytical performances of the multiplex PCR assay G-DiaParaTrio, Allplex® GI parasite and RIDA®GENE parasitic stool panel for detecting Blastocystis sp., Entamoeba histolytica, Giardia duodenalis, Cryptosporidium spp., Dientamoeba fragilis, and Cyclospora cayetanensis, were assessed through a retrospective comparative study on 184 stool samples initially sent for parasitological investigation. The composite reference method for parasitological diagnosis was microscopic observation and Entamoeba histolytica-specific adhesion detection when necessary. Multiplex PCR assays were performed on extracted DNA from each stool, following the manufacturer's recommendations. Discrepant results with the composite reference method were investigated with species-specific PCR to approach a final parasitological diagnosis. Overall sensitivity/specificity for the multiplex PCR assays was 93.2%/100% for G-DiaParaTrio, 96.5%/98.3% for Allplex® GI parasite and 89.6%/98.3% for RIDA®GENE, whereas the composite reference method presented an overall sensitivity/specificity of 59.6%/99.8%. These results confirmed the added diagnostic value of the multiplex PCR approach for gastrointestinal protists. Nevertheless, the PCR procedure and the analytical performance for each protist of interest, variable depending on the multiplex PCR assay, must be considered when implementing a PCR-based diagnostic approach.

TITLE: Sélection d'un panel PCR multiplex pour un diagnostic moléculaire précis des protistes intestinaux : étude comparative des tests Allplex® (Seegene®), G-DiaParaTrio (Diagenode®) et RIDA®GENE (R-Biopharm®) et de l'examen microscopique. ABSTRACT: Des panels commerciaux de tests PCR multiplex ont été développés pour dépasser les limites de l'examen microscopique pour l'examen parasitologique des selles. Cependant, compte tenu de l'offre croissante de cette approche diagnostique, ces tests doivent être évalués pour les positionner dans un algorithme de diagnostic. Les performances analytiques des tests PCR multiplex G-DiaParaTrio, Allplex® GI parasite et RIDA®GENE parasitic stool panel pour la détection de Blastocystis sp., Entamoeba histolytica, Giardia duodenalis, Cryptosporidium spp., Dientamoeba fragilis et Cyclospora cayetanensis, ont été évaluées à travers une étude comparative rétrospective sur 184 échantillons de selles envoyés initialement pour un examen parasitologique. La méthode composite de référence pour le diagnostic parasitologique était l'observation microscopique et la détection d'adhérence spécifique d'Entamoeba histolytica lorsque cela était nécessaire. Des tests PCR multiplex ont été effectués sur l'ADN extrait de chaque selle conformément aux recommandations du fabricant. Les résultats discordants avec la méthode de référence composite ont été étudiés par PCR spécifique d'espèce pour approcher un diagnostic parasitologique final. La sensibilité/spécificité globale des tests PCR multiplex est respectivement de 93,2 %/100 % pour G-DiaParaTrio, 96,5 %/98,3 % pour Allplex® GI et 89,6 %/98,3 % pour RIDA® GENE alors que la méthode de référence composite présente une sensibilité/spécificité globale de 59,6 %/99,8 %. Ces résultats ont confirmé la valeur diagnostique ajoutée de l'approche PCR multiplex pour les protistes gastro-intestinaux. Néanmoins, la procédure de PCR et les performances analytiques pour chaque protiste d'intérêt, variables selon les tests PCR multiplex, doivent être prises en compte lors de la mise en œuvre d'une approche de diagnostic basée sur la PCR.

Impact of TR34/L98H, TR46/Y121F/T289A and TR53 Alterations in Azole-Resistant Aspergillus fumigatus on Sterol Composition and Modifications after In Vitro Exposure to Itraconazole and Voriconazole.

BACKGROUND: Sterols are the main components of fungal membranes. Inhibiting their biosynthesis is the mode of action of azole antifungal drugs that are widely used to treat fungal disease including aspergillosis. Azole resistance has emerged as a matter of concern but little is known about sterols biosynthesis in azole resistant Aspergillus fumigatus. METHODS: We explored the sterol composition of 12 A. fumigatus isolates, including nine azole resistant isolates with TR34/L98H, TR46/Y121F/T289A or TR53 alterations in the cyp51A gene and its promoter conferring azole resistance. Modifications in sterol composition were also investigated after exposure to two azole drugs, itraconazole and voriconazole. RESULTS: Overall, under basal conditions, sterol compositions were qualitatively equivalent, whatever the alterations in the target of azole drugs with ergosterol as the main sterol detected. Azole exposure reduced ergosterol composition and the qualitative composition of sterols was similar in both susceptible and resistant isolates. Interestingly TR53 strains behaved differently than other strains. CONCLUSIONS: Elucidating sterol composition in azole-susceptible and resistant isolates is of interest for a better understanding of the mechanism of action of these drugs and the mechanism of resistance of fungi.

Lethal destructive sinusopathy due to amphotericin B-resistant Aspergillus flavus: A case report

Background:The prevalence of pulmonary aspergillosis and the importance of its early diagnosis are recognized. However, non-pulmonary involvement, including the sinuses region, is not frequently reported, and an infection in this area can affect all paranasal sinuses (pansinusopathy), being a rare pathology that affects immunocompromised hosts. Recent studies have highlighted the occurrence of Aspergillus flavus resistant to antifungal therapy. Therefore, a nasal sinus infection by resistant Aspergillus strains in immunocompromised patients may be linked to a high risk of lethality.Case report:We are reporting a resistant A. flavus infection in an allogeneic hematopoietic stem cell transplant recipient with episodes of febrile neutropenia, and prolonged use of various antibacterial drugs and antifungal prophylaxis. The patient underwent brain magnetic resonance, which showed the presence of pansinusopathy, and presented necrosis in the left nasal region. Direct microscopic examination of a sample taken from the nasal mucosa revealed the presence of septate hyphae and conidiophores resembling those of A. flavus, that species being the identification achieved with MALDI-TOF MS. Antifungigram was performed by microdilution in broth (EUCAST-E.DEF. 9.3.2) and E-test, and resistance to amphotericin B was shown in both tests. The patient died after septic shock and hemorrhage.Conclusions:Invasive fungal infections due to amphotericin-B resistant A. flavus may lead to the death of the patient due to an ineffective therapeutic management. Therefore, antifungal susceptibility testing are of utmost importance for administering the proper treatment. (AU)

Antecedentes:La prevalencia de la aspergilosis pulmonar y la importancia de su diagnóstico precoz son ampliamente conocidos; sin embargo, la afectación extrapulmonar no se informa con frecuencia y son pocos los casos documentados de infección de los senos nasales. Una infección en esta área puede alcanzar todos los senos paranasales (pansinusopatía) cuando afecta a pacientes inmunodeprimidos, lo que agrava la enfermedad preexistente. Estudios recientes han destacado la aparición de cepas que muestran resistencia al tratamiento con fármacos antimicóticos. En el paciente inmunodeprimido una infección de los senos nasales por una cepa de Aspergillus resistente implica un alto riesgo de letalidad.Caso clínico:Presentamos un caso de infección por Aspergillus flavus resistente en un receptor de trasplante alogénico de células madre hematopoyéticas, con episodios de neutropenia febril y uso prolongado de diversos fármacos antibacterianos, además de profilaxis antifúngica. Se realizó una resonancia magnética cerebral que reveló la existencia de pansinusopatía con necrosis en la región nasal izquierda. En el examen microscópico directo de la mucosa nasal se observaron hifas tabicadas y la presencia de conidioforos compatibles con Aspergillus flavus; la identificación con el método MALDI-TOF MS arrojó la especie mencionada. El antifungigrama fue realizado por el método de microdilución en caldo (EUCAST-E.DEF. 9.3.2) y E-test; con ambas técnicas el aislamiento mostró resistencia a la anfotericina B. El paciente falleció tras un shock séptico y hemorragia.Conclusiones:Las infecciones fúngicas invasivas por cepas de Aspergillus flavus resistentes a la anfotericina B puede derivar en la muerte del paciente debido a la ineficacia del tratamiento antifúngico. Es por ello que las pruebas de sensibilidad a los antifúngicos son de suma importancia para establecer así el tratamiento correcto. (AU)

Highly Conserved gsc1 Gene of Pneumocystis jirovecii in Patients with or without Prior Exposure to Echinocandins.

Echinocandins are noncompetitive inhibitors of the GSC1 subunit of the enzymatic complex involved in synthesis of 1,3-beta-d-glucan, a cell wall component of most fungi, including Pneumocystis spp. Echinocandins are widely used for treating systemic candidiasis and rarely used for treating Pneumocystis pneumonia. Consequently, data on P. jirovecii gsc1 gene diversity are still scarce compared to that for the homologous fks1 gene of Candida spp. In this study, we analyzed P. jirovecii gsc1 gene diversity and the putative selection pressure of echinocandins on P. jirovecii. gsc1 gene sequences of P. jirovecii specimens from two patient groups were compared. One group of 27 patients had prior exposure to echinocandins, whereas the second group of 24 patients did not, at the time of P. jirovecii infection diagnoses. Two portions of the P. jirovecii gsc1 gene, HS1 and HS2, homologous to hot spots described in Candida spp., were sequenced. Three single-nucleotide polymorphisms (SNPs) at positions 2204, 2243, and 2303 close to the HS1 region and another SNP at position 4540 more distant from the HS2 region were identified. These SNPs represent synonymous mutations. Three gsc1 HS1 alleles, A, B, and C, and two gsc1 HS2 alleles, a and b, and four haplotypes, Ca, Cb, Aa, and Ba, were defined, without significant difference in haplotype distribution in both patient groups (P = 0.57). Considering the identical diversity of P. jirovecii gsc1 gene and the detection of synonymous mutations in both patient groups, no selection pressure of echinocandins among P. jirovecii microorganisms can be pointed out so far.

Fungal infections in mechanically ventilated patients with COVID-19 during the first wave: the French multicentre MYCOVID study.

BACKGROUND: Patients with severe COVID-19 have emerged as a population at high risk of invasive fungal infections (IFIs). However, to our knowledge, the prevalence of IFIs has not yet been assessed in large populations of mechanically ventilated patients. We aimed to identify the prevalence, risk factors, and mortality associated with IFIs in mechanically ventilated patients with COVID-19 under intensive care. METHODS: We performed a national, multicentre, observational cohort study in 18 French intensive care units (ICUs). We retrospectively and prospectively enrolled adult patients (aged ≥18 years) with RT-PCR-confirmed SARS-CoV-2 infection and requiring mechanical ventilation for acute respiratory distress syndrome, with all demographic and clinical and biological follow-up data anonymised and collected from electronic case report forms. Patients were systematically screened for respiratory fungal microorganisms once or twice a week during the period of mechanical ventilation up to ICU discharge. The primary outcome was the prevalence of IFIs in all eligible participants with a minimum of three microbiological samples screened during ICU admission, with proven or probable (pr/pb) COVID-19-associated pulmonary aspergillosis (CAPA) classified according to the recent ECMM/ISHAM definitions. Secondary outcomes were risk factors of pr/pb CAPA, ICU mortality between the pr/pb CAPA and non-pr/pb CAPA groups, and associations of pr/pb CAPA and related variables with ICU mortality, identified by regression models. The MYCOVID study is registered with ClinicalTrials.gov, NCT04368221. FINDINGS: Between Feb 29 and July 9, 2020, we enrolled 565 mechanically ventilated patients with COVID-19. 509 patients with at least three screening samples were analysed (mean age 59·4 years [SD 12·5], 400 [79%] men). 128 (25%) patients had 138 episodes of pr/pb or possible IFIs. 76 (15%) patients fulfilled the criteria for pr/pb CAPA. According to multivariate analysis, age older than 62 years (odds ratio [OR] 2·34 [95% CI 1·39-3·92], p=0·0013), treatment with dexamethasone and anti-IL-6 (OR 2·71 [1·12-6·56], p=0·027), and long duration of mechanical ventilation (>14 days; OR 2·16 [1·14-4·09], p=0·019) were independently associated with pr/pb CAPA. 38 (7%) patients had one or more other pr/pb IFIs: 32 (6%) had candidaemia, six (1%) had invasive mucormycosis, and one (<1%) had invasive fusariosis. Multivariate analysis of associations with death, adjusted for candidaemia, for the 509 patients identified three significant factors: age older than 62 years (hazard ratio [HR] 1·71 [95% CI 1·26-2·32], p=0·0005), solid organ transplantation (HR 2·46 [1·53-3·95], p=0·0002), and pr/pb CAPA (HR 1·45 [95% CI 1·03-2·03], p=0·033). At time of ICU discharge, survival curves showed that overall ICU mortality was significantly higher in patients with pr/pb CAPA than in those without, at 61·8% (95% CI 50·0-72·8) versus 32·1% (27·7-36·7; p<0·0001). INTERPRETATION: This study shows the high prevalence of invasive pulmonary aspergillosis and candidaemia and high mortality associated with pr/pb CAPA in mechanically ventilated patients with COVID-19. These findings highlight the need for active surveillance of fungal pathogens in patients with severe COVID-19. FUNDING: Pfizer.

Collateral consequences of agricultural fungicides on pathogenic yeasts: A One Health perspective to tackle azole resistance.

Candida and Cryptococcus affect millions of people yearly, being responsible for a wide array of clinical presentations, including life-threatening diseases. Interestingly, most human pathogenic yeasts are not restricted to the clinical setting, as they are also ubiquitous in the environment. Recent studies raise concern regarding the potential impact of agricultural use of azoles on resistance to medical antifungals in yeasts, as previously outlined with Aspergillus fumigatus. Thus, we undertook a narrative review of the literature and provide lines of evidence suggesting that an alternative, environmental route of azole resistance, may develop in pathogenic yeasts, in addition to patient route. However, it warrants sound evidence to support that pathogenic yeasts cross border between plants, animals and humans and that environmental reservoirs may contribute to azole resistance in Candida or other yeasts for humans. As these possibilities could concern public health, we propose a road map for future studies under the One Health perspective.

Genotypic, proteomic, and phenotypic approaches to decipher the response to caspofungin and calcineurin inhibitors in clinical isolates of echinocandin-resistant Candida glabrata.

BACKGROUND: Echinocandin resistance represents a great concern, as these drugs are recommended as first-line therapy for invasive candidiasis. Echinocandin resistance is conferred by mutations in FKS genes. Nevertheless, pathways are crucial for enabling tolerance, evolution, and maintenance of resistance. Therefore, understanding the biological processes and proteins involved in the response to caspofungin may provide clues indicating new therapeutic targets. OBJECTIVES: We determined the resistance mechanism and assessed the proteome response to caspofungin exposure. We then evaluated the phenotypic impact of calcineurin inhibition by FK506 and cephalosporine A (CsA) on caspofungin-resistant Candida glabrata isolates. METHODS: Twenty-five genes associated with caspofungin resistance were analysed by NGS, followed by studies of the quantitative proteomic response to caspofungin exposure. Then, susceptibility testing of caspofungin in presence of FK506 and CsA was performed. The effects of calcineurin inhibitor/caspofungin combinations on heat stress (40°C), oxidative stress (0.2 and 0.4 mM menadione) and on biofilm formation (polyurethane catheter) were analysed. Finally, a Galleria mellonella model using blastospores (1 × 109 cfu/mL) was developed to evaluate the impact of the combinations on larval survival. RESULTS: F659-del was found in the FKS2 gene of resistant strains. Proteomics data showed some up-regulated proteins are involved in cell-wall biosynthesis, response to stress and pathogenesis, some of them being members of calmodulin-calcineurin pathway. Therefore, the impact of calmodulin inhibition was explored. Calmodulin inhibition restored caspofungin susceptibility, decreased capacity to respond to stress conditions, and reduced biofilm formation and in vivo pathogenicity. CONCLUSIONS: Our findings confirm that calmodulin-calcineurin-Crz1 could provide a relevant target in life-threatening invasive candidiasis.

In vitro antifungal effect of a plant-based product, CIN-102, on antifungal resistant filamentous fungi and their biofilms.

Introduction. The increase of invasive fungal infections (IFIs) and associated treatment failure in populations at risk is driving us to look for new treatments.Hypothesis. The CIN-102 compound, derived from cinnamon essential oil, could be a new antifungal class with an activity, in particular, on strains resistant to current antifungals but also on biofilms, a factor of virulence and resistance of fungi.Aim. The aim of this study is to show the activity of CIN-102 on various strains resistant to current antifungals, on the biofilm and to determine the possibility of resistance induced with this compound.Methodology. We studied the MIC of CIN-102 and of current antifungals (voriconazole and amphotericin B) using CLSI techniques against eight different strains of three genera of filamentous fungi involved in IFIs and having resistance phenotypes to current antifungals. We also determined their effects on biofilm formation, and the induced resistance by voriconazole (VRC) and CIN-102.Results. MIC values determined for CIN-102 were between 62.5 and 250 µg ml-1. We demonstrated the antifungal effect of CIN-102 on biofilm, and more particularly on its formation, with 100 % inhibition achieved for most of the strains. CIN-102 at a sub-inhibitory concentration in the medium did not induce resistance in our strains, even after 30 generations.Conclusions. In this study we show that CIN-102 is effective against resistant filamentous fungi and against biofilm formation. In addition, our strains did not acquire a resistance phenotype against CIN-102 over time, unlike with VRC. CIN-102 is therefore an interesting candidate for the treatment of IFIs, including in cases of therapeutic failure linked to resistance, although further studies on its efficacy, safety and mechanism of action are needed.

Confocal spectral microscopy, a non-destructive approach to follow contamination and biofilm formation of mCherry Staphylococcus aureus on solid surfaces.

Methods to test the safety of wood material for hygienically sensitive places are indirect, destructive and limited to incomplete microbial recovery via swabbing, brushing and elution-based techniques. Therefore, we chose mCherry Staphylococcus aureus as a model bacterium for solid and porous surface contamination. Confocal spectral laser microscope (CSLM) was employed to characterize and use the autofluorescence of Sessile oak (Quercus petraea), Douglas fir (Pseudotsuga menziesii) and poplar (Populus euramericana alba L.) wood discs cut into transversal (RT) and tangential (LT) planes. The red fluorescent area occupied by bacteria was differentiated from that of wood, which represented the bacterial quantification, survival and bio-distribution on surfaces from one hour to one week after inoculation. More bacteria were present near the surface on LT face wood as compared to RT and they persisted throughout the study period. Furthermore, this innovative methodology identified that S. aureus formed a dense biofilm on melamine but not on oak wood in similar inoculation and growth conditions. Conclusively, the endogenous fluorescence of materials and the model bacterium permitted direct quantification of surface contamination by using CSLM and it is a promising tool for hygienic safety evaluation.

Anti-protozoal and anti-fungal evaluation of 3,5-disubstituted 1,2-dioxolanes.

Endoperoxides are a class of compounds, which is well-known for their antimalarial properties, but few reports exist about 3,5-disubstituted 1,2-dioxolanes. After having designed a new synthetic route for the preparation of these substances, they were evaluated against 4 different agents of infectious diseases, protozoa (Plasmodium and Leishmania) and Fungi (Candida and Aspergillus). Whereas moderate antifungal activity was found for our products, potent antimalarial and antileishmanial activities were observed for a few compounds. The nature of the substituents linked to the endoperoxide ring seems to play an important role in the bioactivities.