Identification of two different 14-alpha sterol demethylase-related genes (cyp51A and cyp51B) in Aspergillus fumigatus and other Aspergillus species

Erratum in: J Clin Microbiol 2001 Nov;39(11):4225.Two cyp51-related genes (cyp51A and cyp51B) encoding 14-alpha sterol demethylase-like enzymes were identified in the opportunistic human pathogen Aspergillus fumigatus. PCR amplification using degenerate oligonucleotides based on conserved areas of cytochrome P450 demethylases of other filamentous fungi and yeasts allowed the cloning and sequencing of two different homologue genes in A. fumigatus. Southern analysis confirmed that both genes hybridized to distinct genomic loci and that both are represented as single copies in the genome. Comparison of the deduced Cyp51A and Cyp51B proteins with the CYP51 proteins from Penicillium italicum, Aspergillus nidulans, Erysiphe graminis, Uncinula necator, Botrytis cinerea, Ustilago maydis, Cryptococcus neoformans, Candida albicans, Saccharomyces cerevisiae, Candida tropicalis, and Candida glabrata showed that the percentages of identity of the amino acid sequences (range, 40 to 70%) were high enough to consider Cyp51A and Cyp51B to be members of the fungal CYP51 family. Fragments from both genes were also cloned from other Aspergillus spp. (A. flavus, A. nidulans, and A. terreus). Phylogenetic analysis showed that, at least in the most pathogenic species of Aspergillus, there are two fungal CYP51 proteins. This is the first report of the existence of two homologue genes coding for 14-alpha sterol demethylase in the fungal kingdom. This finding could provide insights into the azole resistance mechanisms operating in fungi. The primers used here may be useful molecular tools for facilitating the cloning of novel 14-alpha sterol demethylase genes in other filamentous fungi.This work was supported in part by grant 1078/99 from Instituto de Salud Carlos III. T.M.D.-G. is a fellow of the Instituto de Salud Carlos III

Clinical indications for therapeutic drug monitoring of antifungal agents. In the way for optimizing the treatment of fungal infection

[ES] La monitorización de fármacos se ha consolidado en los últimos años como una herramienta útil, y en algunos casos esencial, en el manejo de las enfermedades infecciosas. En las infecciones fúngicas, la posibilidad de monitorizar las concentraciones sanguíneas de los antifúngicos ha supuesto un valor añadido en el manejo de esta patología infecciosa. Las especiales características farmacocinéticas de estos fármacos y de sus formulaciones dificultan el correcto empleo que asegure su eficacia y minimice su toxicidad. La monitorización de las concentraciones plasmáticas puede mejorar la utilización de estos agentes antiinfecciosos, así como facilitar el manejo de las interacciones medicamentosas, la patología y los efectos adversos teniendo como consecuencia un ahorro en costes derivados de tratamientos y dosificaciones inadecuadas. En estarevisión se evalúa el papel de la monitorización clínica de los antifúngicos que están actualmente disponibles en la práctica clínica, con una dedicación casi exclusiva a los compuestas azólicos. [EN] Therapeutic drug monitoring as a tool in the management of infectious diseases has been introduced in therapy with anti-infective agents for years. Nowadays, it has taken importance in the management of fungal diseases due to the appearance of new antifungal drugs such as new-generation azoles. These azoles have pharmacokinetic characteristics that hinder a proper use to ensure efficacy and minimize toxicity. Monitoring of serum concentrations may help in the better use of these anti-infective agents, as well as in a better management of drug interactions, infectious disease and adverse effects. It has resulted in saving costs of treatment and in avoiding inadequate dosages. This review will attempt to clarify the role of the antifungal agents Therapeutic Drug Monitoring, highlighting the role of azole compounds.S

Fungal Cell Gigantism during Mammalian Infection

The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 µm in diameter and capsules resistant to stripping with γ-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20–50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens

Echinocandin susceptibility testing of Candida spp. using the EUCAST EDef 7.1 and CLSI M27-A3 standard procedures: Analysis of the influence of Bovine Serum Albumin Supplementation, Storage Time and Drug Lots

The MICs of echinocandins against Candida isolates with fks mutations are higher than those for wild-type (WT) isolates. However, the MIC ranges for susceptible and mutant populations overlap or are poorly separated. It was recently reported that a greater separation could be achieved in the presence of serum. To more fully explore this possibility, we compared the performances of the reference microdilution methods by using standard and bovine serum albumin (BSA)-supplemented growth medium. Anidulafungin, caspofungin, and micafungin MICs were determined according to EUCAST and CLSI methods and with 50% BSA in the medium for 93 clinical isolates, including Candida albicans (20/10 [number of isolates/number of mutants]), C. glabrata (19/10), C. dubliniensis (2/1), C. krusei (16/3), C. parapsilosis (19), and C. tropicalis (19/4) isolates. Stability of the plates was tested after storage at -80°C for 2 and 6 months, and the performance of two different lots of caspofungin was investigated. The addition of BSA to the medium resulted in higher MICs (1 to 9 2-fold dilution steps) for all isolates and compounds. The increases were greatest for anidulafungin and micafungin and, among WT isolates, for C. parapsilosis. The number of very major errors (VMEs) was reduced (24% [20/84 isolates] versus ≤ 7% [6/84 isolates]) using BSA-supplemented EUCAST medium but not using BSA-supplemented CLSI medium (6% versus 9%). MIC results were unchanged after 6 months of storage of test plates. The two lots of caspofungin yielded identical results. Addition of BSA to the EUCAST medium increases the ability to differentiate between WT isolates and isolates harboring resistance mutations.Fil: Arendrup, Maiken Cavling. Statens Serum Institut. Unit of Mycology and Parasitology; DinamarcaFil: Rodriguez Tudela, Juan Luis. Instituto de Salud Carlos III. Centro Nacional de Microbiología. Servicio de Micología; EspañaFil: Park, Steven. UMDNJ-New Jersey Medical School. Public Health Research Institute; Estados UnidosFil: Garcia, Guillermo Manuel. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. UMDNJ-New Jersey Medical School. Public Health Research Institute; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe; ArgentinaFil: Delmas, Guillaume. UMDNJ-New Jersey Medical School. Public Health Research Institute; Estados UnidosFil: Cuenca Estrella, Manuel. Instituto de Salud Carlos III. Centro Nacional de Microbiología. Servicio de Micología; EspañaFil: Gómez López, Alicia. Instituto de Salud Carlos III. Centro Nacional de Microbiología. Servicio de Micología; EspañaFil: Perlin, David Scott. UMDNJ-New Jersey Medical School. Public Health Research Institute; Estados Unido

Capsule enlargement in Cryptococcus neoformans confers resistance to oxidative stress suggesting a mechanism for intracellular survival

Cryptococcus neoformans is a facultative intracellular pathogen. The most distinctive feature of C. neoformans is a polysaccharide capsule that enlarges depending on environmental stimuli. The mechanism by which C. neoformans avoids killing during phagocytosis is unknown. We hypothesized that capsule growth conferred resistance to microbicidal molecules produced by the host during infection, particularly during phagocytosis. We observed that capsule enlargement conferred resistance to reactive oxygen species produced by H(2)O(2) that was not associated with a higher catalase activity, suggesting a new function for the capsule as a scavenger of reactive oxidative intermediates. Soluble capsular polysaccharide protected C. neoformans and Saccharomyces cerevisiae from killing by H(2)O(2). Acapsular mutants had higher susceptibility to free radicals. Capsular polysaccharide acted as an antioxidant in the nitroblue tetrazolium (NBT) reduction coupled to beta-nicotinamide adenine dinucleotide (NADH)/phenazine methosulfate (PMS) assay. Capsule enlargement conferred resistance to antimicrobial peptides and the antifungal drug Amphotericin B. Interestingly, the capsule had no effect on susceptibility to azoles and increased susceptibility to fluconazole. Capsule enlargement reduced phagocytosis by environmental predators, although we also noticed that in this system, starvation of C. neoformans cells produced resistance to phagocytosis. Our results suggest that capsular enlargement is a mechanism that enhances C. neoformans survival when ingested by phagocytic cells.We thank Dr J.D. Nosanchuk for the use of defensins and Dr Steinman for the kind gift of A. castellanii strains. We thank Dr J.C. Arguelles and Pilar González (Universidad de Murcia, Spain) for providing protocols to measure catalase activity, and Drs Carlos and Juana Maria Gancedo (CSIC, Spain) for the permission to use their technical resources and for their helpful discussions. We are indebted to Dr F. Usera and Rosa Hidalgo for their collaboration, help and technical support in the use of the γ-irradiator from the animal facility from the National Center for Biotechnology (CSIC, Spain). We warmly thank Josefa Casas for her technical support, and all the members from the Mycology Service from the National Center for Microbiology (Instituto de Salud Carlos III) for their helpful discussions. M.V.C. is funded by a research contract from the Agencia Española de Cooperación Internacional (AECI). O.Z. is a ‘Ramón y Cajal’ fellow from the Ministerio Español de Educación y Ciencia (MEC) and is funded by Grants MPY1025/06 from the MEC and 1181/06 from el Instituto de Salud Carlos III.S

Método para la detección simultánea de histoplasma capsulatum y paracoccidioides brasiliensis

La presente invención se refiere a un método de detección simultánea de ADN de Histoplasma capsulatum y Paracoccidioides brasiliensis mediante la técnica de PCR multiplex cuantitativa en tiempo real, basada en sondas específicas marcadas con dos fluoróforos diferentes. Esta técnica es aplicable tanto en muestras biológicas como en cultivos microbiológicos y muestras ambientales. Además, otro aspecto de la invención es un kit que permite detectar los dos microorganismos de forma simultánea.REIVINDICACIONES: 1. Método para la detección simultánea de Histoplasma capsulatum y Paracoccidioides brasiliensis que comprende: a. obtener una muestra y aislar su ADN, b. amplificar un fragmento de la región ITS del ADN ribosómico de Histoplasma capsulatum y/o Paracoccidioides brasiliensis contenido en el ADN aislado en el paso (a) , c. determinar la desviación del paso (b) con respecto a los controles y d. analizar la desviación del paso (c) y atribuir la misma a la presencia de los citados microorganismos. 2. Método según la reivindicación 1 donde la concentración del ADN aislado para llevar a cabo la amplificación es de al menos 10 fg/μl. 3. Método según la reivindicación 1 donde la muestra es: a. una muestra biológica, b. un cultivo microbiológico o c. una muestra ambiental. 4. Método según la reivindicación 3 donde la muestra biológica está relacionada con el aparato respiratorio. 5. Método según cualquiera de las reivindicaciones 1 a 4 donde la amplificación de la región ITS2 del ADN ribosómico de Histoplasma capsulatum se realiza por medio de los cebadores SEQ ID NO: 1 y SEQ ID NO: 2 y la amplificación de la región ITS1 del ADN ribosómico de Paracoccidioides brasiliensis se realiza por medio de los cebadores SEQ ID NO: 4 y SEQ ID NO: 5. 6. Método según cualquiera de las reivindicaciones 1 a 5 donde la amplificación se realiza por medio de PCR multiplex en tiempo real caracterizada porque se emplean sondas específicas marcadas con dos fluoróforos diferentes. 7. Método según la reivindicación 6 donde las sondas son: a. SEQ ID NO: 3 para el fragmento amplificado de Histoplasma capsulatum y se marca en el extremo 5' con un fluoróforo y en el extremo 3' con un quencher y b. SEQ ID NO: 6 para el fragmento amplificado de Paracoccidioides brasiliensis y se marca en el extremo 5' con un fluoróforo distinto del usado en el apartado (a) y en el extremo 3' con un quencher. 8. Método según la reivindicación 7 donde el fluoróforo del apartado (a) es FAM, el fluoróforo del apartado (b) es HEX y el quencher es BHQ1. 9. Método según cualquiera de las reivindicaciones 1 a 8, para la monitorización de la respuesta a un tratamiento de histoplasmosis y/o paracoccidioidomicosis. 10. Kit para la detección simultánea de Histoplasma capsulatum y Paracoccidioides brasiliensis que comprende pares de cebadores que pueden amplificar, mediante la técnica de la PCR, un fragmento de la región ITS del ADN ribosómico de Histoplasma capsulatum y/o Paracoccidioides brasiliensis. 11. Kit según la reivindicación 10 que comprende los cebadores SEQ ID NO: 1 y SEQ ID NO: 2 para amplificar un fragmento de la región ITS2 del ADN ribosómico de Histoplasma capsulatum y los cebadores SEQ ID NO: 4 y SEQ ID NO: 5 para amplificar un fragmento de la región ITS1 del ADN ribosómico de Paracoccidioides brasiliensis. 12. Kit según la cualquiera de las reivindicaciones 10 u 11 donde la amplificación se realiza por medio de PCR multiplex en tiempo real y se emplean sondas específicas marcadas con dos fluoróforos diferentes. 13. Kit según la reivindicación 12 donde las sondas son: a. SEQ ID NO: 3 para el fragmento amplificado de Histoplasma capsulatum y se marca en el extremo 5'con un fluoróforo y en el extremo 3' con un quencher y b. SEQ ID NO: 6 para el fragmento amplificado de Paracoccidioides brasiliensis y se marca en el extremo 5' con un fluoróforo distinto del usado en el apartado (a) y en el extremo 3' con un quencher. 14. Kit según la reivindicación 13 donde el fluoróforo del apartado (a) es FAM, el fluoróforo del apartado (b) es HEX y el quencher es BHQ1. 15. Kit según cualquiera de las reivindicaciones 10 a 14, para el diagnóstico de histoplasmosis y/o paracoccidioidomicosis en una muestra biológica, ambiental o en un cultivo microbiológico. 16. Kit según cualquiera de las reivindicaciones 10 a 14, para la monitorización de la respuesta a un tratamiento de histoplasmosis y/o paracoccidioidomicosis.Cuando una patente se hace internacional, se puede encontrar en el idioma de cada país en que se ha solicitado. En Espacenet se tiene acceso a los documentos en cada idioma.Instituto de Salud Carlos IIISolicitud de patent

Susceptibility patterns and molecular identification of Trichosporon species

The physiological patterns, the sequence polymorphisms of the internal transcriber spacer (ITS), and intergenic spacer regions (IGS) of the rRNA genes and the antifungal susceptibility profile were evaluated for their ability to identify Trichosporon spp. and their specificity for the identification of 49 clinical isolates of Trichosporon spp. Morphological and biochemical methodologies were unable to differentiate among the Trichosporon species. ITS sequencing was also unable to differentiate several species. However, IGS1 sequencing unambiguously identified all Trichosporon isolates. Following the results of DNA-based identification, Trichosporon asahii was the species most frequently isolated from deep sites (15 of 25 strains; 60%). In the main, other Trichosporon species were recovered from cutaneous samples. The majority of T. asahii, T. faecale, and T. coremiiforme clinical isolates exhibited resistance in vitro to amphotericin B, with geometric mean (GM) MICs >4 mug/ml. The other species of Trichosporon did not show high MICs of amphotericin B, and GM MICs were <1 mug/ml. Azole agents were active in vitro against the majority of clinical strains. The most potent compound in vitro was voriconazole, with a GM MIC </=0.14 mug/ml. The sequencing of IGS correctly identified Trichosporon isolates; however, this technique is not available in many clinical laboratories, and strains should be dispatched to reference centers where these complex methods are available. Therefore, it seems to be more practical to perform antifungal susceptibility testing of all isolates belonging to Trichosporon spp., since correct identification could take several weeks, delaying the indication of an antifungal agent which exhibits activity against the infectious strain.S

Pharmacokinetics of Echinocandins in Suspected Candida Peritonitis: a Potential Risk for Resistance.

A possible increase of Candida resistance, specially in C. glabrata, has been speculated according to a poor diffusion of echinocandins to peritoneal fluid. Peritoneal and serum concentrations of Caspofungin, micafungin and anidulafungin were analyzed in surgical patients with suspected candida peritonitis. After four days of starting therapy serum and peritoneal samples (through peritoneal drainage) were obtained at baseline, 1 h, 6 h, 12 h, and 24 h of drug administration. Micafungin and anidulafungin concentrations were determined using high-performance liquid chromatography (HPLC/F), whereas caspofungin concentration were stablished by bioassay. A total of 23 critically ill patients with suspected abdominal fungal infection who were receiving an echinocandin were prospectively recruited. No specific criteria were applied to prescribe one specific echinocadin. No special clinical differences were observed among the 3 groups of patients. All were receiving antibiotic therapy, 80% required inotropic drugs and finally fungal peritonitis were confirmed in 74% of them. The AUC0_24h (mg*h/L) obtained in serum and peritoneal fluid were: 126.84 and 34.38; 98.52 and 18.83; and 66.9 and 8.78 for anidulafungin, micafungin and caspofungin, respectively. The median concentration in peritoneal fluid ranged from 0.66 to 1.82 μg/ml for anidulafungin, 0.68 to 0.88 μg/mL for micafungin and 0.21 to 0.46 μg/ml for caspofungin. The results show a moderate penetration of echinocandins into the peritoneal fluid in these patients. These levels are below the threshold of resistance mutant selection published by other authors. It could justify a potential risk of resistance in patients with prolonged treatments with echinocandins and suboptimal control of the abdominal infection.The study received funding from the “Fondo de Investigaciones Sanitarias” of the Spanish Ministry of Health (FIS PI 15/1536). The work was supported by Plan Nacional de I + D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases (REIPI RD16), and co-financed by European Development Regional Fund “A way to achieve Europe”, Operative program Intelligent Growth 2014-2020.S

Performance of a Quantitative PCR-Based Assay and Beta-d-Glucan Detection for Diagnosis of Invasive Candidiasis in Very-Low-Birth-Weight Preterm Neonatal Patients (CANDINEO Study)

An epidemiological, multicenter, noninterventional, observational case-control study was conducted to describe the performance of serum beta-d-glucan (BDG) and Candida PCR in blood, serum, and sterile samples for the diagnosis of invasive candidiasis (IC) in very-low-birth-weight (VLBW) preterm neonates and to compare these techniques with culture of samples from blood and other sterile sites. Seventeen centers participated in the study, and the number of episodes analyzed was 159. A total of 9 episodes of IC from 9 patients (7 confirmed and 2 probable) and 150 episodes of suspected sepsis from 117 controls were identified. The prevalence of IC was 5.7% (95% confidence interval [95% CI], 2.1 to 9.3). The mortality was significantly higher in episodes of IC (44.4%) than in the non-IC episodes (11.1%, P < 0.01). The sensitivity and specificity of the PCR performed on blood/serum samples were 87.5% and 81.6%, respectively. The sensitivity and specificity of the BDG results were lower (75.0% and 64.6%). For cases with negative culture results, the PCR and the BDG results were positive in 27 (17.4%) and 52 (33.5%) episodes, respectively. The presence of multiorgan failure, improvement with empirical antifungal therapy, thrombocytopenia, and Candida colonization were significantly associated (P < 0.01) with PCR or BDG positivity regardless of the results of the cultures. Serum BDG analysis and Candida PCR could be used as complementary diagnostic techniques to detect IC in VLBW neonates.This study was initiated and financially supported by Astellas Pharma Inc. Manuel Cuenca-Estrella has received grant support from Astellas Pharma Inc., bioMérieux, Basilea, Gilead Sciences, Merck Sharp & Dohme, Pfizer, Schering Plough, Soria Melguizo SA, Ferrer International, the European Union, the ALBAN program, the Spanish Agency for International Cooperation, the Spanish Ministry of Culture and Education, the Spanish Health Research Fund, Instituto de Salud Carlos III (Spanish Ministry of Economy and Competitiveness), the Ramon Areces Foundation, and the Mutua Madrileña Foundation. Jose T. Ramos has received fees for conferences from Gilead Sciences, ViiV Healthcare, and Janssen-Cilag and grant support from the Gilead Fellowship Program. Elena Bergon-Sendin received grant support from Astellas Pharma Inc. during the conduct of the study. Paloma Anguita Alonso is an employee of Astellas Pharma Inc. The rest of us have no conflicts to report. Medical writing support was provided by Lucy Kanan on behalf of Bioscript Medical Ltd., funded by Astellas Pharma IncS

Resolution of disseminated fusariosis in a child with acute leukemia treated with combined antifungal therapy: a case report

<p>Abstract</p> <p>Background</p> <p><it>Fusarium </it>spp. is being isolated with increasing frequency as a pathogen in oncohematologic patients. Caspofungin and amphotericin B have been reported to have synergistic activity against <it>Fusarium </it>spp.</p> <p>Case presentation</p> <p>We herein report a case of disseminated fusariosis diagnosed by chest CT scan and positive blood cultures to <it>Fusarium </it>spp. Because the patient's clinical condition deteriorated, CRP levels increased, and blood cultures continued to yield <it>Fusarium </it>spp. despite liposomal amphotericin B monotherapy up to 5 mg/kg daily, treatment with caspofungin was added. Within 2 weeks of onset of combined antifungal therapy, the chest CT scan demonstrated a progressive resolution of the pulmonary lesions. Upon discontinuation of intravenous antifungals, the patient received suppressive therapy with oral voriconazole. Three months later, a chest CT scan showed no abnormalities. Twenty-five months after discontinuation of all antifungal therapy, the patient remains in complete remission of her neoplastic disease with no signs of clinical activity of the <it>Fusarium </it>infection.</p> <p>Conclusion</p> <p>This is the first description of successful treatment of disseminated fusariosis in a pediatric patient with acute lymphoblastic leukemia with caspofungin and amphotericin B followed by oral suppressive therapy with voriconazole.</p