Microwave-Assisted Synthesis of Aminophosphonic Derivatives and Their Antifungal Evaluation against Lomentospora prolificans.

Lomentospora prolificans is a pathogenic and multidrug-resistant fungus that can infect both immunocompetent and immunocompromised patients, with mortality rates up to 87%. The World Health Organization (WHO) included this fungal species in its first list of 19 priority fungal pathogens, which focused on fungal pathogens that can cause invasive acute and subacute systemic fungal infections. Therefore, there is a growing interest in finding new therapeutic alternatives. In this work, the synthesis of twelve α-aminophosphonates by the microwave-assisted Kabachnik-Fields reaction and twelve α-aminophosphonic acids by a monohydrolysis reaction is reported. All compounds were evaluated by the agar diffusion method as a preliminary screening in comparison with voriconazole, showing inhibition halos for compounds 7, 11, 13, 22 and 27. The five active compounds in the preliminary tests were evaluated against five strains of L. prolificans following protocol M38-A2 from CLSI. The results showed that these compounds exhibit antifungal activity in the concentration range of 900->900 µg/mL. Cytotoxicity against healthy COS-7 cells was also evaluated by the MTT assay, and it was shown that compound 22 was the least cytotoxic, with a viability of 67.91%, comparable to the viability exhibited by voriconazole (68.55%). Docking studies showed that the possible mechanism of action of the active compounds could be through the inhibition of the enzyme lanosterol-14-alpha-demethylase in an allosteric hydrophobic cavity.

Evaluation of the synergistic antifungal activity of micafungin and voriconazole plus sertraline against Candida auris.

Candida auris is an emerging global public health threat. It is an opportunistic yeast that usually affects critically ill patients in healthcare settings and is characterized by reduced susceptibility to multiple antifungal classes. Combination therapy with antifungals and repurposed drugs is a feasible alternative to overcome this problem. The aim of this study was to examine the in vitro interactions and potential synergy of micafungin (MFG) and voriconazole (VRC) plus the antidepressant sertraline (SRT) against clinical isolates of C. auris. Conventional antifungal testing was first performed with the three drugs according to the CLSI methodology. Drug interactions were determined by the checkerboard microdilution assay using the fractional inhibitory concentration (FIC) index. Synergistic interactions were noted with the combination of MFG and SRT plus VRC with FIC values of 0.37 to 0.49 for some strains. Indifferent interactions were observed when MFG was combined with SRT with just one exception (FIC 0.53). No antagonism was observed for any combination. The combination of VRC with MCF or SRT may be relevant for treating C. auris infections.

Novel α-Aminophosphonates and α-Aminophosphonic Acids: Synthesis, Molecular Docking and Evaluation of Antifungal Activity against Scedosporium Species.

The Scedosporium genus is an emerging pathogen with worldwide prevalence and high mortality rates that gives multidrug resistance to antifungals; therefore, pharmacological alternatives must be sought for the treatment of diseases caused by this fungus. In the present project, six new α-aminophosphates were synthesized by the Kabachnik-Fields multicomponent reaction by vortex agitation, and six new monohydrolyzed α-aminophosphonic acids were synthesized by an alkaline hydrolysis reaction. Antifungal activity was evaluated using the agar diffusion method as an initial screening to determine the most active compound compared to voriconazole; then it was evaluated against 23 strains of the genus Scedosporium following the M38-A2 protocol from CLSI (activity range: 648.76-700 µg/mL). Results showed that compound 5f exhibited the highest antifungal activity according to the agar diffusion method (≤1 mg/mL). Cytotoxicity against healthy COS-7 cells was also evaluated by the MTT assay and it was shown that compound 5f exhibits a lower toxicity in comparison to voriconazole at the same concentration (1000 µM). A docking study was conducted afterwards, showing that the possible mechanism of action of the compound is through the inhibition of allosteric 14-α-demethylase. Taking these results as a basis, 5f is presented as a compound with attractive properties for further studies.

Managing raw materials of vegetable origin increases fungal indoor concentration in food companies.

Fungi in indoor environments is a known cause of disease and food spoilage. However, there is currently no legislation or normativity stablishing limits for fungal densities in correlation with these. Moreover, there is little knowledge of the diversity of fungi in indoor environments for industrial areas and in food-related companies in particular, a study has never been performed to evaluate the concentration and diversity of fungi in this type of places. We evaluated the fungal density of 20 food companies. We sampled 100 L of air onto rose bengal-malt extract-agar plates, using an Air Test Omega® sampler. After incubation, CFUs were counted and identified. Penicillium, Cladosporium and Aspergillus were the most commonly isolated genus, with Penicillium being the only genus to be present in every area sampled. Neither the companies' location nor their room temperature influenced the fungal densities significantly, however, companies using vegetable raw materials had a significantly greater concentration of fungi than the rest of the companies. While all concentrations were within previously suggested levels from a health-related point of view, more information is needed that correlates fungal concentration with food spoilage in order to suggest a range of concentrations focused for food companies' product preservation.

In vivo evaluation of the antifungal activity of sertraline against Aspergillus fumigatus.

BACKGROUND: Invasive pulmonary aspergillosis is a life-threatening fungal disease principally caused by the ubiquitous mould Aspergillus fumigatus. This clinical entity is a major cause of morbidity and mortality (principally, but not restricted to, immunocompromised individuals). A few recent reports suggest in vitro fungicidal activity of sertraline against Aspergillus spp., but this activity has not yet been investigated in vivo. OBJECTIVES: To evaluate the antifungal activity of sertraline in two in vivo models of aspergillosis. METHODS: The antifungal activity of sertraline as monotherapy at three different doses (3, 10 and 15 mg/kg) was evaluated in Galleria mellonella and in a murine model of invasive pulmonary aspergillosis. Therapeutic efficacy parameters determined were larval survival and health index score for G. mellonella, whereas pulmonary fungal burden, galactomannan and lung histopathology were assessed in the murine model. RESULTS: Sertraline treatments improved larval survival and health index score, especially at doses of 10 and 15 mg/kg. Moreover, 10 mg/kg sertraline was able to reduce pulmonary fungal burden with an efficacy comparable with that of 3 mg/kg amphotericin B and 10 mg/kg voriconazole. CONCLUSIONS: To the best of our knowledge, this is the first in vivo study that evaluates the antifungal activity of sertraline against A. fumigatus, showing a possible promising option for the adjuvant treatment of pulmonary aspergillosis.

Phenotypical characterization and molecular identification of clinical isolates of Candida tropicalis / Caracterización fenotípica e identificación molecular de aislamientos clínicos de Candida tropicalis

Background. Candida tropicalis is an increasingly important human pathogen which usually affects neutropenic oncology patients with common hematogenous seeding to peripheral organs and high mortality rates. Candida pathogenicity is facilitated by several virulence attributes, including secretion of hydrolytic enzymes; however, little is known regarding the C. tropicalis ability to secrete them and their role in the disease. Aims. To confirm by molecular means the identification of 187 clinical isolates (127 from blood, 52 from urine, and 8 from diverse clinical origins) phenotypically identified as C. tropicalis, and to investigate their in vitro aspartyl proteinase, phospholipase, esterase, hemolysin, DNase and coagulase activities. Methods. The molecular confirmation was performed by ITS sequencing, and the enzymatic determinations were conducted using plate assays with specific substrates, with the exception of coagulase, which was determined by the classical tube test. Results. The majority of the strains exhibited a very strong or strong activity of aspartyl proteinase, phospholipase and esterase. A 4.7% of the bloodstream isolates were hemolysin producers, and all were negative for the coagulase and DNase assays. Conclusions. Very strong activities of aspartyl proteinase, phospholipase and esterase profiles were detected, and a statistical association between phospholipase production and blood and urine isolates was found (AU)

Antecedentes. Candida tropicalis es un patógeno del ser humano cada vez más importante que afecta especialmente a pacientes oncológicos neutropénicos, en los cuales es frecuente la diseminación hematógena del microorganismo a órganos periféricos, lo que conlleva elevadas tasas de mortalidad. La patogenicidad de Candida es facilitada por diversos factores de virulencia, incluyendo la secreción de enzimas hidrolíticas; sin embargo, poco se sabe respecto a la habilidad de C. tropicalis para su secreción, así como el papel que desempeña en la enfermedad. Objetivos. Confirmar por un método molecular la identidad de 187 aislamientos clínicos (127 de sangre, 52 de orina y 8 de orígenes diversos) fenotípicamente identificados como C. tropicalis y estudiar la actividad in vitro de las enzimas proteinasa aspártica, fosfolipasa, esterasa, hemolisina, DNasa y coagulasa. Métodos. La confirmación molecular se llevó a cabo mediante secuenciación del ITS y las determinaciones enzimáticas se llevaron a cabo mediante ensayos en placa con sustratos específicos, a excepción de la coagulasa, que se determinó mediante la clásica prueba en tubo. Resultados. La mayoría de los aislamientos analizados mostraron un perfil de actividad muy fuerte o fuerte de proteinasa aspártica, fosfolipasa y esterasa. El 4,7% de las cepas sanguíneas fue productora de hemolisinas y todas fueron negativas para coagulasa y DNasa. Conclusiones. Se detectaron perfiles con una actividad proteinasa aspártica, fosfolipasa y esterasa muy fuerte entre los aislamientos clínicos analizados, así como también se encontró asociación estadística entre la producción de fosfolipasa y aquellos aislamientos obtenidos de sangre y orina (AU)

Phenotypical characterization and molecular identification of clinical isolates of Candida tropicalis.

BACKGROUND: Candida tropicalis is an increasingly important human pathogen which usually affects neutropenic oncology patients with common hematogenous seeding to peripheral organs and high mortality rates. Candida pathogenicity is facilitated by several virulence attributes, including secretion of hydrolytic enzymes; however, little is known regarding the C. tropicalis ability to secrete them and their role in the disease. AIMS: To confirm by molecular means the identification of 187 clinical isolates (127 from blood, 52 from urine, and 8 from diverse clinical origins) phenotypically identified as C. tropicalis, and to investigate their in vitro aspartyl proteinase, phospholipase, esterase, hemolysin, DNase and coagulase activities. METHODS: The molecular confirmation was performed by ITS sequencing, and the enzymatic determinations were conducted using plate assays with specific substrates, with the exception of coagulase, which was determined by the classical tube test. RESULTS: The majority of the strains exhibited a very strong or strong activity of aspartyl proteinase, phospholipase and esterase. A 4.7% of the bloodstream isolates were hemolysin producers, and all were negative for the coagulase and DNase assays. CONCLUSIONS: Very strong activities of aspartyl proteinase, phospholipase and esterase profiles were detected, and a statistical association between phospholipase production and blood and urine isolates was found.

Comparative Pathogenicity of Lomentospora prolificans (Scedosporium prolificans) Isolates from Mexican Patients.

We identified 11 Lomentospora prolificans isolates recovered from Mexican patients using phenotypic and molecular characteristics. The identification of isolates was assessed by internal transcribed spacer (ITS rDNA) sequencing. In vitro susceptibility to amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin and micafungin was determined according to Clinical and Laboratory Standards Institute (CLSI) procedures. Three isolates (07-2239, 11-2242 and 04-2673) were used to induce systemic infection in immunocompetent ICR mice. Survival and tissue burden studies were used as markers of pathogenicity. All of the strains were resistant to every antifungal tested with MIC's for AmB (8->8 µg/ml), VRC (16->16 µg/ml), PSC (16->16 µg/ml), FLC (64->64 µg/ml) and echinocandins with MICs ≥8 µg/ml. One hundred, ninety and sixty percent of the infected mice with the strains 07-2239, 11-2242 and 04-2673 died during the study, respectively. Regarding tissue burden, the highest fungal load of the infected mice was detected in brain followed by spleen and kidney, regardless of the strain.

Molecular identification and in vitro antifungal susceptibility of Scedosporium complex isolates from high-human-activity sites in Mexico.

The genus Scedosporium is a complex of ubiquitous moulds associated with a wide spectrum of clinical entities, with high mortality principally in immunocompromised hosts. Ecology of these microorganisms has been studied performing isolations from environmental sources, showing a preference for human-impacted environments. This study aimed to evaluate the presence and antifungal susceptibility of Scedosporium complex species in soil samples collected in high-human-activity sites of Mexico. A total of 97 soil samples from 25 Mexican states were collected. Identifications were performed by microscopic morphology and confirmed by sequencing of the rDNA (internal transcribed spacer [ITS], D1/D2) and ß-tubulin partial loci. Antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) protocols. Soil samples of urban gardens and industrial parks constituted the best sources for isolation of Scedosporium complex species. S. apiospermum sensu stricto was the most prevalent species (69%), followed by S. boydii (16%). Voriconazole (minimal inhibitory concentration [MIC] geometric mean ≤2.08 µg/mL), followed by posaconazole (MIC geometric mean ≤2.64 µg/mL), exhibited excellent in vitro activity for most species. Amphotericin B and fluconazole demonstrated limited antifungal activity, and all of the strains were resistant to echinocandins. This is the first report in Mexico of environmental distribution and antifungal in vitro susceptibility of these emergent pathogens.

Candida parapsilosis complex induces local inflammatory cytokines in immunocompetent mice.

Despite the increasing incidence of the Candida parapsilosis complex in the clinical setting and high mortality rates associated with disseminated infection, the host-fungus interactions regarding Candida parapsilosis sensu stricto and the closely related species C. orthopsilosis and C. metapsilosis remains blurred. In this study, we analyzed inflammatory cytokines levels and histopathology as well as fungal burden in spleen, kidney and lung of mice infected with six strains of the "psilosis" group with different enzymatic profiles. Strong interleukin 22 (IL-22) and tumor necrosis factor α (TNF-α) responses were observed in analyzed organs from infected mice (P < .0001) regardless of the species and enzymatic profile. TNF-α and IL-22 levels were related with spleen inflammation and fungal load. Fungal cells were detected only in spleen and kidney of infected mice, especially by day 2 post-challenge. The kidney showed glomerular retraction and partial destruction of renal tubules. Our data suggest that a strong inflammatory response, mainly of IL-22 and TNF-α, could be involved in Candida parapsilosis complex infection control.

Efficacy of ravuconazole in a murine model of vaginitis by Candida albicans / Eficacia del ravuconazol en un modelo murino de vaginitis por Candida albicans

Background. The incidence of vulvovaginal candidiasis, a common infection among healthy women primarily caused by the yeast Candida albicans, has increased significantly in recent years. Aims. The purpose of this study was to compare the efficacy of ravuconazole (RVC) and fluconazole (FLC) in the treatment of experimental C. albicans vaginitis. Methods. Forty isolates of C. albicans were screened for their in vitro susceptibility to RVC and FLC. A strain of C. albicans that was resistant to FLC (minimum inhibitory concentration [MIC] of >64 μg/ml) was selected for the in vivo study. Treatment regimens for the murine vaginal infection model were (1) 1, 5, 10, and 20 mg/kg RVC once daily, (2) 20 mg/kg RVC twice daily, (3) 20 mg/kg FLC once daily, and (4) 20 mg/kg FLC twice daily. Results. The geometric means of the MIC values at 48 h for all isolates tested were 0.05 and 0.5 μg/ml for RVC and FLC, respectively. Regimens of either RVC or FLC at 20 mg/kg twice daily were more effective to reduce the load of FLC-resistant C. albicans than single dose administration. Conclusions. Complete eradication of C. albicans from the vagina was not observed with RVC or FLC treatment in the animal model, although RVC treatment showed a lower fungal concentration 14 days after drug administration (AU)

Antecedentes. En los últimos años, ha aumentado sustancialmente la incidencia de candidiasis vulvovaginal, una infección frecuente entre mujeres sanas, causada sobre todo por la levadura Candida albicans. Objetivos. El objetivo del presente estudio fue comparar la eficacia del ravuconazol (RVC) y del fluconazol (FLC) en el tratamiento de la vaginitis experimental inducida por C. albicans. Métodos. Se examinó la sensibilidad in vitro de 40 aislamientos de C. albicans frente a RVC y FLC. Para el estudio in vivo se seleccionó una cepa de C. albicans que fue resistente a FLC (concentración inhibitoria mínima [CIM] >64 μg/ml). Las pautas de tratamiento para el modelo murino de infección vaginal fueron 1) 1, 5, 10 y 20 mg/kg de RVC una vez al día, 2) 20 mg/kg de RVC dos veces al día, 3) 20 mg/de FLC una vez al día, y 4) 20 mg/kg de FLC dos veces al día. Resultados. Para todos los aislamientos las medias geométricas de los valores de la CIM a las 48 h fueron de 0,05 y 0,5 μg/ml para RVC y FLC, respectivamente. Las pautas de 20 mg/kg de RVC o FLC dos veces al día fueron más eficaces para reducir la carga infectiva de C. albicans resistente a FLC que las administradas una vez al día. Conclusiones. En el modelo animal no se eliminó completamente C. albicans del tracto vaginal estéril mediante tratamiento con RVC o FLC. Sin embargo, el tratamiento con RVC derivó en concentraciones fúngicas más bajas 14 días después de su administración (AU)

Efficacy of ravuconazole in a murine model of vaginitis by Candida albicans.

BACKGROUND: The incidence of vulvovaginal candidiasis, a common infection among healthy women primarily caused by the yeast Candida albicans, has increased significantly in recent years. AIMS: The purpose of this study was to compare the efficacy of ravuconazole (RVC) and fluconazole (FLC) in the treatment of experimental C. albicans vaginitis. METHODS: Forty isolates of C. albicans were screened for their in vitro susceptibility to RVC and FLC. A strain of C. albicans that was resistant to FLC (minimum inhibitory concentration [MIC] of >64 µg/ml) was selected for the in vivo study. Treatment regimens for the murine vaginal infection model were (1) 1, 5, 10, and 20 mg/kg RVC once daily, (2) 20 mg/kg RVC twice daily, (3) 20 mg/kg FLC once daily, and (4) 20 mg/kg FLC twice daily. RESULTS: The geometric means of the MIC values at 48 h for all isolates tested were 0.05 and 0.5 µg/ml for RVC and FLC, respectively. Regimens of either RVC or FLC at 20 mg/kg twice daily were more effective to reduce the load of FLC-resistant C. albicans than single dose administration. CONCLUSIONS: Complete eradication of C. albicans from the vagina was not observed with RVC or FLC treatment in the animal model, although RVC treatment showed a lower fungal concentration 14 days after drug administration.

Killer behavior within the Candida parapsilosis complex.

A group of 29 isolates of Candida parapsilosis sensu stricto, 29 of Candida orthopsilosis, and 4 of Candida metapsilosis were assayed for the presence of killer activity using Saccharomyces cerevisiae ATCC 26609 as a sensitive strain. All C. metapsilosis isolates showed killer activity at 25 °C while strains of C. parapsilosis sensu stricto or C. orthopsilosis did not exhibit this activity. Sensitivity to killer toxins was evaluated using a set of previously reported killer strains of clinical origin. Only 11 isolates of the C. parapsilosis complex were inhibited by at least one killer isolate without resulting in any clear pattern, except for C. parapsilosis sensu stricto ATCC 22019, which was inhibited by every killer strain with the exception of C. parapsilosis and Candida utilis. The lack of sensitivity to killer activity among isolates of the genus Candida suggests that their toxins belong to the same killer type. Differentiation of species within the C. parapsilosis complex using the killer system may be feasible if a more taxonomically diverse panel of killer strains is employed.

Susceptibility of Dermatophytes to Thiabendazole Using CLSI Broth Macrodilution.

Objective. To evaluate in vitro antifungal activity of thiabendazole against strains of dermatophytes using a reference method for filamentous fungi. Materials and Methods. Dermatophytes' susceptibility to thiabendazole (TBZ) and fluconazole (FCZ) was evaluated using macrodilution method of protocol M38-A2 of the Clinical and Laboratory Standards Institute (CLSI). Results. MIC ranges of TBZ for all strains were narrower and/or smaller than those of FCZ. TBZ showed a significantly greater potency than FCZ (P = 0.05) against all isolates. Discussion. Although there have been approaches to evaluate the antifungal activity of TBZ in human mycoses, no tests had been made with a standardized protocol. Susceptibility data resulted from this study shows that although TBZ is not a particularly strong inhibitor of dermatophytes, it displays a stable and constant effect against all isolates tested. Conclusion. Results show that TBZ is more effective against strains of dermatophytes than FCZ. We acknowledge the antifungal effect of TBZ against dermatophyte isolates.