RESUMEN
The synthetic cytokinin forchlorfenuron (FCF), while seemingly presenting relatively low toxicity for mammalian organisms, has been the subject of renewed scrutiny in the past few years due to its increasing use in fruit crops and potential for bioaccumulation. Despite many toxicological properties of FCF being known, little research has been conducted on the toxicological effects of its secondary metabolites. Given this critical gap in the existing literature, understanding the formation of relevant FCF secondary metabolites and their association with mammalian metabolism is essential. To investigate the formation of FCF metabolites in sufficient quantities for toxicological studies, a panel of four fungi were screened for their ability to catalyze the biotransformation of FCF. Of the organisms screened, Cunninghamella elegans (ATCC 9245), a filamentous fungus, was found to convert FCF to 4-hydroxyphenyl-forchlorfenuron, the major FCF secondary metabolite identified in mammals, after 26 days. Following the optimization of biotransformation conditions using a solid support system, media screening, and inoculation with a solid pre-formed fungal mass of C. elegans, this conversion time was significantly reduced to 7 days-representing a 73% reduction in total reaction time as deduced from the biotransformation products and confirmed by LC-MS, NMR spectroscopic data, as well as a comparison with synthetically prepared metabolites. Our study provides the first report of the metabolism of FCF by C. elegans. These findings suggest that C. elegans can produce FCF secondary metabolites consistent with those produced via mammalian metabolism and could be used as a more efficient, cost-effective, and ethical alternative for producing those metabolites in useful quantities for toxicological studies.
RESUMEN
The impact of antiretroviral therapy (ART) on opportunistic conditions in HIV patients continues to evolve. We specifically studied the changing epidemiology of oropharyngeal candidiasis (OPC) in 215 HIV/AIDS patients. Status of yeast colonization was assessed from oral rinse samples, and preliminary yeast identification was made using CHROMagar Candida and confirmed with standard microbiological techniques and/or molecular sequencing. Susceptibility to fluconazole was determined by CHROMagar Candida agar dilution screening and CLSI broth microdilution. 176 (82%) patients were colonized and 59 (27%) patients had symptomatic OPC. Candida albicans was the most prevalent species, though C. glabrata and C. dubliniensis were detected in 29% of isolates. Decreased fluconazole susceptibility occurred in 10% of isolates. Previous ART reduced the risk of OPC, while smoking increased the risk of colonization. Oral yeast colonization and symptomatic infection remain common even with advances in HIV therapy. C. albicans is the most common species, but other yeasts are prevalent and may have decreased susceptibility to fluconazole.
RESUMEN
OBJECTIVES: Amphotericin B inhalation powder (ABIP) is a novel dry-powder amphotericin B formulation that is directly delivered to the lung, resulting in elevated lung tissue drug concentrations of this polyene. We evaluated the prophylactic efficacy of single dose administration of ABIP in a guinea pig model of invasive pulmonary aspergillosis. METHODS: Guinea pigs were immunosuppressed with cyclophosphamide and cortisone acetate and challenged with Aspergillus fumigatus conidia in an aerosol chamber. Guinea pigs received prophylaxis with a single inhaled dose of ABIP at 0.05, 0.5, 4 or 10 mg/kg administered 24 h prior to infection. Treatment with oral voriconazole at doses of 5 or 10 mg/kg twice daily beginning 24 h post-challenge served as the positive control. RESULTS: Improvements in survival were observed with ABIP prophylaxis. A single inhaled dose of 4 mg/kg ABIP and treatment with 5 mg/kg voriconazole both improved median and percentage survival compared with untreated controls. In addition, pulmonary fungal burden, as assessed by cfu, quantitative PCR and galactomannan, was also reduced in a dose-dependent fashion with ABIP prophylaxis as well as with both doses of voriconazole treatment. CONCLUSIONS: Single-dose prophylaxis with inhaled ABIP as prophylaxis demonstrated a significant survival advantage and reductions in pulmonary fungal burden in this model of invasive pulmonary aspergillosis. Optimization of the dose and dosing frequency of ABIP dose may help to further enhance the anti-Aspergillus activity of this novel amphotericin B formulation.
Asunto(s)
Anfotericina B/administración & dosificación , Antifúngicos/administración & dosificación , Aspergillus fumigatus/patogenicidad , Quimioprevención/métodos , Aspergilosis Pulmonar Invasiva/prevención & control , Administración por Inhalación , Animales , Aspergillus fumigatus/efectos de los fármacos , Recuento de Colonia Microbiana , Cortisona/administración & dosificación , Cortisona/análogos & derivados , Ciclofosfamida/administración & dosificación , Modelos Animales de Enfermedad , Cobayas , Inmunosupresores/administración & dosificación , Pulmón/microbiología , Masculino , Pirimidinas/administración & dosificación , Análisis de Supervivencia , Triazoles/administración & dosificación , VoriconazolRESUMEN
We report a case of fluconazole-resistant oropharyngeal colonization caused by a strain of Candida glabrata that rapidly regained susceptibility once prophylaxis with this agent was discontinued and echinocandin therapy was initiated. Isolates collected before and after discontinuation of fluconazole were confirmed to be isogenic by RAPD analysis. Transcription analysis demonstrated constitutive expression of genes encoding efflux pumps in the isolate recovered on fluconazole prophylaxis and transient expression in those isolates collected after fluconazole was discontinued.
Asunto(s)
Antifúngicos/uso terapéutico , Candida glabrata/efectos de los fármacos , Quimioprevención/métodos , Farmacorresistencia Fúngica , Fluconazol/uso terapéutico , Trasplante de Células Madre Hematopoyéticas , Antifúngicos/farmacología , Candida glabrata/clasificación , Candida glabrata/genética , Candida glabrata/aislamiento & purificación , Candidiasis/microbiología , Portador Sano/microbiología , Dermatoglifia del ADN , ADN de Hongos/genética , Equinocandinas/uso terapéutico , Fluconazol/farmacología , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Técnicas de Tipificación Micológica , Orofaringe/microbiología , Técnica del ADN Polimorfo Amplificado AleatorioRESUMEN
We measured antifungal activity against 128 cryptococcal isolates (86 of C. neoformans and 42 of C. gattii) to determine if differences in serotype susceptibility exist. Contrary to previous results, we found no serotype susceptibility differences. Isavuconazole, posaconazole, and voriconazole demonstrated excellent potency against each isolate and serotype, including isolates with reduced fluconazole susceptibilities.
Asunto(s)
Antifúngicos/farmacología , Cryptococcus neoformans/efectos de los fármacos , Cryptococcus/efectos de los fármacos , Cryptococcus/clasificación , Cryptococcus neoformans/clasificación , Fluconazol/farmacología , Pruebas de Sensibilidad Microbiana , Nitrilos/farmacología , Piridinas/farmacología , Pirimidinas/farmacología , Serotipificación , Triazoles/farmacología , VoriconazolRESUMEN
We report a case of Candida glabrata invasive candidiasis that developed reduced susceptibility to caspofungin during prolonged therapy. Pre- and posttreatment isolates were confirmed to be isogenic, and sequencing of hot spots known to confer echinocandin resistance revealed an F659V substitution within the FKS2 region of the glucan synthase complex.
Asunto(s)
Antifúngicos/farmacología , Candida glabrata/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Candidiasis/microbiología , Equinocandinas/farmacología , Adulto , Sustitución de Aminoácidos , Secuencia de Bases , Candida glabrata/enzimología , Candida glabrata/genética , Caspofungina , Cartilla de ADN/genética , ADN de Hongos/genética , Farmacorresistencia Fúngica/genética , Genes Fúngicos , Glucosiltransferasas/genética , Humanos , LipopéptidosRESUMEN
We compared Etest with broth microdilution testing for isavuconazole activity against 92 Cryptococcus isolates. A 97.8% agreement was found between these methods, without major discrepancies (>2-well dilution difference). Our findings support the use of the Etest methodology as a reliable method for the determination of MICs against Cryptococcus spp.
Asunto(s)
Cryptococcus neoformans/efectos de los fármacos , Cryptococcus/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Nitrilos/farmacología , Piridinas/farmacología , Triazoles/farmacología , Antifúngicos/farmacología , Reproducibilidad de los Resultados , Especificidad de la EspecieRESUMEN
Early diagnosis of invasive pulmonary aspergillosis is problematic in some patient groups due to the lack of rapid, sensitive, specific, and reliable diagnostic tests. Fungal burden and therapeutic efficacy were assessed by survival, quantitative culture (CFU counts), galactomannan enzyme immunoassay (GM-EIA), and quantitative PCR (qPCR) in a new guinea pig model of invasive pulmonary aspergillosis using an aerosol challenge. At 1 day postinfection, qPCR determined that the pulmonary fungal burden was 2 log(10) higher than that determined by CFU counting and increased significantly (P < 0.03) over time. In contrast, the tissue burden assessed by CFU counting did not rise over the course of the study. Therapy with the antifungal drug voriconazole produced statistically significant decreases in pulmonary fungal burden, as detected by CFU counting (P < 0.02), qPCR, and GM-EIA (both P < 0.0002). Daily assessment of the progression of fungal infection in serum was performed by qPCR and GM-EIA. GM-EIA demonstrated a statistically significant reduction in the fungal load on days 6 and 7 in voriconazole-treated animals compared to time-matched controls (P < 0.02). Confirmation of fungal tissue burden by two or more methods should provide a more precise account of the burden, allowing improved assessment of diagnostic and therapeutic strategies in invasive pulmonary aspergillosis.
Asunto(s)
Aspergilosis/diagnóstico , Aspergillus fumigatus/aislamiento & purificación , Enfermedades Pulmonares Fúngicas/diagnóstico , Animales , Antifúngicos/uso terapéutico , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Aspergillus fumigatus/química , Aspergillus fumigatus/genética , Secuencia de Bases , Recuento de Colonia Microbiana , Cartilla de ADN/genética , ADN de Hongos/genética , Modelos Animales de Enfermedad , Galactosa/análogos & derivados , Cobayas , Humanos , Técnicas para Inmunoenzimas/métodos , Pulmón/microbiología , Pulmón/patología , Enfermedades Pulmonares Fúngicas/tratamiento farmacológico , Enfermedades Pulmonares Fúngicas/microbiología , Masculino , Mananos/análisis , Micología/métodos , Reacción en Cadena de la Polimerasa/métodos , Pirimidinas/uso terapéutico , Triazoles/uso terapéutico , VoriconazolRESUMEN
Serum (1-->3)-beta-D-glucan concentrations were serially measured in the presence and absence of antifungal therapy in a murine model of invasive pulmonary aspergillosis. Serum (1-->3)-beta-D-glucan was detected early during the course of infection, and reductions in this biomarker were associated with improved survival in animals treated with antifungal agents.
Asunto(s)
Antifúngicos/uso terapéutico , Aspergilosis , Aspergillus fumigatus , Biomarcadores/sangre , Enfermedades Pulmonares Fúngicas , beta-Glucanos/sangre , Animales , Animales no Consanguíneos , Aspergilosis/diagnóstico , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Aspergilosis/mortalidad , Aspergillus fumigatus/efectos de los fármacos , Aspergillus fumigatus/aislamiento & purificación , Modelos Animales de Enfermedad , Humanos , Pulmón/microbiología , Enfermedades Pulmonares Fúngicas/diagnóstico , Enfermedades Pulmonares Fúngicas/tratamiento farmacológico , Enfermedades Pulmonares Fúngicas/microbiología , Enfermedades Pulmonares Fúngicas/mortalidad , Ratones , Ratones Endogámicos ICR , Proteoglicanos , Resultado del TratamientoRESUMEN
Evaluating new therapeutic agents for invasive aspergillosis requires animal models that are reproducible among different laboratories. We therefore evaluated a murine model of aerosol infection in two independent laboratories and found a high level of both intra- and interlaboratory reproducibility of survival, fungal burden over time, and the efficacy of liposomal amphotericin B.
Asunto(s)
Aspergilosis , Aspergillus fumigatus/patogenicidad , Modelos Animales de Enfermedad , Enfermedades Pulmonares Fúngicas , Anfotericina B/uso terapéutico , Animales , Antifúngicos/uso terapéutico , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Aspergilosis/mortalidad , Aspergillus fumigatus/aislamiento & purificación , Humanos , Liposomas , Pulmón/microbiología , Enfermedades Pulmonares Fúngicas/tratamiento farmacológico , Enfermedades Pulmonares Fúngicas/microbiología , Enfermedades Pulmonares Fúngicas/mortalidad , Ratones , Reproducibilidad de los Resultados , Resultado del TratamientoRESUMEN
Antagonistic effects of combination therapy using amphotericin B (AmB) with agents which block ergosterol synthesis are a concern. Terbinafine was evaluated with AmB to assess antagonism or synergy in a rabbit model of invasive aspergillosis. Terbinafine had relatively little activity but did not demonstrate antagonism against AmB in our model.