Search Results (40)

In this study, a series of novel β-phenylalanine derivatives were synthesised and evaluated for their anticancer activity. The 3-(4-methylbenzene-1-sulfonamido)-3-phenylpropanoic acid (2) was prepared using β-phenylalanine as a core scaffold. The β-amino acid derivative 2 was converted to the corresponding hydrazide 4, which enabled the development of structurally diverse heterocyclic derivatives including pyrrole 5, pyrazole 6, thiadiazole 8, oxadiazole 11, triazoles 9 and 12 with Schiff base analogues 13 and series1,2,4-triazolo [3,4-b][1,3,4]thiadiazines 14. These modifications were designed to enhance chemical stability, solubility, and biological activity. All compounds were initially screened for cytotoxicity against the A549 human lung adenocarcinoma cell line, identifying N-[3-(3,5-dimethyl-1H-pyrazol-1-yl)-3-oxo-1-phenylpropyl]-4-methylbenzenesulfonamide (5) and (E)-N-{2-[4-[(4-chlorobenzylidene)amino]-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]-1-phenylethyl}-4-methylbenzenesulfonamide (13b) as the most active. The two lead candidates were further evaluated in H69 and H69AR small cell lung cancer lines to assess activity in drug-sensitive and multidrug-resistant models. Schiff base 13b containing a 4-chlorophenyl moiety, retained potent antiproliferative activity in both H69 and H69AR cells, comparable to cisplatin, while compound 5 lost efficacy in the resistant phenotype. These findings suggest Schiff base derivative 13b may overcome drug resistance mechanisms, a limitation commonly encountered with standard chemotherapeutics such as doxorubicin. These results demonstrate the potential role of β-phenylalanine derivatives, azole-containing sulphonamides, as promising scaffolds for the development of novel anticancer agents, particularly in the context of lung cancer and drug-resistant tumours. Full article

To address the surge in Aspergillus fumigatus infections among immunosuppressed patients and azole resistance, this study focused on developing novel inhibitors targeting dihydroorotate dehydrogenase (AfDHODH), a key enzyme in fungal pyrimidine synthesis. The three-dimensional structure of AfDHODH was constructed via homology modeling. Molecular docking, dynamics simulations, and binding free energy calculations systematically elucidated the mechanisms of existing inhibitors. Virtual screening against the ZINC20 and ChEMBL databases yielded 13 candidates, with two micromolar inhibitors (IC₅₀ < 100 μM) identified through in vitro assays. These inhibitors exhibited novel scaffold structures that were distinct from known DHODH inhibitors. The results validate the feasibility of homology modeling-guided antifungal discovery and these findings provide critical insights for the development of new antifungal agents. Full article

Background/Objectives: Eumycetoma, caused by Madurella mycetomatis, is a chronic fungal infection with limited treatment options and increasing drug resistance. CYP51, a key enzyme in ergosterol biosynthesis, is a well-established target for azole antifungals. However, existing azole drugs demonstrate limited efficacy in treating eumycetoma. Microbial-based natural products, with their structural diversity and bioactivity, offer a promising source for novel CYP51 inhibitors. This study aimed to identify potential Madurella mycetomatis CYP51 inhibitors from microbial natural products using molecular docking, MM-GBSA calculations, ADMET analysis, and molecular dynamics (MD) simulations. Methods: Virtual screening was conducted on a library of microbial-based natural products using an in-house homology model of Madurella mycetomatis CYP51, with itraconazole as the reference drug. The top compounds from initial docking were refined through Standard and Extra Precision docking. MM-GBSA calculations assessed binding affinities, and ADMET analysis evaluated drug-like properties. Compounds with favorable properties underwent MD simulations. Results: The computational investigations identified 34 compounds with better docking scores and binding affinity than itraconazole. Of these, 9 compounds interacted with the heme group and key residues in the active site of Madurella mycetomatis CYP51. In silico pharmacokinetic profiling identified 3 compounds as promising candidates, and MD simulations confirmed their potential as CYP51 inhibitors. Conclusions: The study highlights microbial-derived natural products, particularly monacyclinone G, H, and I, as promising candidates for Madurella mycetomatis CYP51 inhibition, with the potential for treating eumycetoma, requiring further experimental validation. Full article

Background: Candidiasis remains a chief concern in global healthcare. Drug safety issues and increasing resistance make it urgent to develop alternative antifungal agents, namely antimicrobial peptides. Amidated decoralin (Dec-CONH₂) possesses considerable anti-Candida activity, and its association with nanocarriers could help in enhancing efficacy while reducing intrinsic toxicity to the host. Methods: We studied an N-terminal cysteine-modified version of the peptide (Cys-Dec-CONH₂) and screened the effects of different nanosystems (polymeric nanoparticles (NPs), liposomes and gold NPs) on its activity against azole-sensitive and azole-resistant Candida species using a clinically relevant in vitro assay. Results: The antifungal activity of Cys-Dec-CONH₂ was maintained (minimum inhibitory concentration (MIC) = 16–64 µg/mL), but the presence of poly(d,l-lactic-co-glycolic acid) (PLGA)- and polycaprolactone-based NPs impaired the antifungal effect of the peptide (MIC > 256 µg/mL). This effect was milder for polystyrene-based NPs, liposomes, and gold NPs (MIC ≤ 128 µg/mL). Additionally, the covalent surface functionalization of PLGA-based NPs with Cys-Dec-CONH₂ or the presence of relevant biomolecules (albumin and mucin) resulted in complete inhibition of antifungal activity. Conclusions: Our data suggest that Cys-Dec-CONH₂ is able to establish strong interfacial interactions with different nanomaterials, which need to be considered when developing nanomedicines based on this peptide for the management of candidiasis. Full article

Fungal resistance is a public health concern due to the limited availability of antifungal resources and the complexities associated with treating persistent fungal infections. Azoles are thus far the primary line of defense against fungi. Specifically, azoles inhibit the conversion of lanosterol to ergosterol, producing defective sterols and impairing fluidity in fungal plasmatic membranes. Studies on azole resistance have emphasized specific point mutations in CYP51/ERG11 proteins linked to resistance. Although very insightful, the traditional approach to studying azole resistance is time-consuming and prone to errors during meticulous alignment evaluation. It relies on a reference-based method using a specific protein sequence obtained from a wild-type (WT) phenotype. Therefore, this study introduces a machine learning (ML)-based approach utilizing molecular descriptors representing the physiochemical attributes of CYP51/ERG11 protein isoforms. This approach aims to unravel hidden patterns associated with azole resistance. The results highlight that descriptors related to amino acid composition and their combination of hydrophobicity and hydrophilicity effectively explain the slight differences between the resistant non-wild-type (NWT) and WT (nonresistant) protein sequences. This study underscores the potential of ML to unravel nuanced patterns in CYP51/ERG11 sequences, providing valuable molecular signatures that could inform future endeavors in drug development and computational screening of resistant and nonresistant fungal lineages. Full article

Acanthamoeba spp. can cause a sight threatening disease. At present, the current treatments used to treat Acanthamoeba spp. Infections, such as biguanide-based antimicrobials, remain inefficacious, with the appearance of resistant forms and high cytotoxicity to host cells. In this study, an initial screening was conducted against Acanthamoeba castellanii Neff and murine macrophages J774A.1 using alamarBlue™. Among the 160 compounds included in the cited box, 90% exhibited an inhibition of the parasite above 80%, while only 18.75% of the compounds inhibited the parasite with a lethality towards murine macrophage lower than 20%. Based on the amoebicidal activity, the cytotoxicity assay, and availability, Terconazole was chosen for the elucidation of the action mode in two clinical strains, Acanthamoeba culbertsoni and Acanthamoeba castellanii L10. A fluorescence image-based system and proteomic techniques were used to investigate the effect of the present azole on the cytoskeleton network and various programmed cell death features, including chromatin condensation and mitochondria dysfunction. Taking all the results together, we can suggest that Terconazole can induce programmed cell death (PCD) via the inhibition of sterol biosynthesis inhibition. Full article

In recent years, a significant number of infections have been attributed to non-albicidal Candida species (NAC), mainly due to the increasing resistance of NAC to antifungal agents. As only a few antifungal agents are available (azoles, echinocandins, polyenes, allylamines and nucleoside analogues), it is very important to look for possible alternatives to inhibit resistant fungi. One possibility could be essential oils (EOs), which have been shown to have significant antifungal and antibacterial activity. Therefore, in this study, the efficacy of 12 EOs and their combinations was evaluated against four yeasts of the genus Candida (C. albicas, C. glabrata, C. tropicalis and C. parapsilosis). GC-MS and GC-MS FID techniques were used for the chemical analysis of all EOs. VITEK-2XL was used to determine the antifungal susceptibility of the tested Candida spp. strains. The agar disc diffusion method was used for primary screening of the efficacy of the tested EOs. The broth dilution method was used to determine the minimum inhibitory concentrations (MICs) of the most potent EOs. After MIC cultivation, the minimum fungicidal concentration (MFC) was determined on Petri dishes (60 mm). The synergistic effect of combined EOs was evaluated using the checkerboard method and expressed as a fractional inhibitory concentration index (FICI). The results showed that ginger > ho-sho > absinth > dill > fennel > star anise > and cardamom were the most effective EOs. For all Candida species tested, the synergy was mainly observed in these combinations: ginger/fennel for C. albicans FICI 0.25 and C. glabrata, C. tropicalis and C. parapsilosis FICI 0.5 and absinth/fennel for C. albicans FICI 0.3125, C. tropicalis FICI 0.3125 and C. parapsilosis FICI 0.375. Our results suggest that the resistance of fungal pathogens to available antifungals could be reduced by combining appropriate EOs. Full article

The relationship between fungal species and their resistance patterns in vineyard soils has important implications for agriculture and medicine. This study explored the prevalence of Aspergillus section Fumigati species and their resistance to azole compounds in Romanian vineyard soils. Methods: A total of 265 soil samples from various Romanian vineyards were screened for fungi resistant to azoles. Results: Aspergillus section Fumigati isolates exhibited significant resistance to itraconazole and voriconazole, but no azole-resistant Aspergillus fumigatus strains were detected. Six percent of the samples were positive for Aspergillus section Fumigati strains, all of which were azole-resistant. The strains were mainly Aspergillus udagawae (93.75%) and Aspergillus lentulus (6.25%). The predominant azole-resistant Aspergillus species were Aspergillus section Nigri strains, which were found in 75 soil samples. Conclusions: This study highlights the importance of understanding fungal resistance in vineyard soils for both the agricultural and clinical sectors. The presence of resistant strains may affect vine health and wine production while also constituting a challenge in the selection of effective treatments against severe and potentially fatal fungal infections in humans, stressing the importance of species-specific antifungal resistance knowledge. Full article

(1) Background: Aspergillus flavus is a cosmopolitan mold with medical, veterinary, and agronomic concerns. Its morphological similarity to other cryptic species of the Flavi section requires molecular identification techniques that are not routinely performed. For clinical isolates of Aspergillus section Flavi, we present the molecular identification, susceptibility to six antifungal agents, and clinical context of source patients. (2) Methods: One hundred forty fungal clinical isolates were included in the study. These isolates, recovered over a 15-year period (2001–2015), were identified based on their morphological characteristics as belonging to section Flavi. After the subculture, sequencing of a part of the β-tubulin and calmodulin genes was performed, and resistance to azole antifungals was screened on agar plates containing itraconazole and voriconazole. Minimum inhibitory concentrations were determined for 120 isolates by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. (3) Results: Partial β-tubulin and calmodulin sequences analysis showed that 138/140 isolates were A. flavus sensu stricto, 1 isolate was A. parasiticus/sojae, and 1 was A. nomiae. Many of the isolates came from samples collected in the context of respiratory tract colonization. Among probable or proven aspergillosis, respiratory infections were the most frequent, followed by ENT infections. Antifungal susceptibility testing was available for isolates (n = 120, all A. flavus ss) from one hospital. The MIC range (geometric mean MIC) in mg/L was 0.5–8 (0.77), 0.5–8 (1.03), 0.125–2 (0.25), 0.03–2 (0.22), 0.25–8 (1.91), and 0.03–0.125 (0.061) for voriconazole, isavuconazole, itraconazole, posaconazole, amphotericin B, and caspofungin, respectively. Two (1.67%) isolates showed resistance to isavuconazole according to current EUCAST breakpoints with MICs at 8 mg/L for isavuconazole and voriconazole. One of these two isolates was also resistant to itraconazole with MIC at 2 mg/L. (4) Conclusions: The present characterization of a large collection of Aspergillus belonging to the Flavi section confirmed that A. flavus ss is the predominant species. It is mainly implicated in respiratory and ENT infections. The emergence of resistance highlights the need to perform susceptibility tests on section Flavi isolates. Full article

Candida auris has become a major concern in critical care medicine due to the increasing number of immunocompromised patients and candidiasis is the most frequent cause of fungal infections. C. auris and other fungal pathogens are responsible for at least 13 million infections and 1.5 million deaths globally per year. In immunocompromised patients, infections can quickly become severe, causing wound infections, otitis and candidemia, resulting in high morbidity and mortality. The clinical presentation of C. auris is often non-specific and similar to other types of systemic infections; in addition, it is harder to identify from cultures than other, more common types of Candida spp. Some infections are particularly difficult to treat due to multi-resistance to several antifungal agents, including fluconazole (and other azoles), amphotericin B and echinocandins. This entails treatment with more drugs and at higher doses. Even after treatment for invasive infections, patients generally remain colonized for long periods, so all infection control measures must be followed during and after treatment of the C. auris infection. Screening patients for C. auris colonization enables facilities to identify individuals with C. auris colonization and to implement infection prevention and control measures. This pathogenic fungus shows an innate resilience, enabling survival and persistence in healthcare environment and the ability to rapidly colonize the patient’s skin and be easily transmitted within the healthcare setting, thus leading to a serious and prolonged outbreak. Full article

Concern about the global emergence of multidrug-resistant fungal pathogens led us to explore the use of combination therapy to combat azole resistance in Candida auris. Clorgyline had previously been shown to be a multi-target inhibitor of Cdr1 and Mdr1 efflux pumps of Candida albicans and Candida glabrata. A screen for antifungal sensitizers among synthetic analogs of Clorgyline detected interactions with the C. auris efflux pump azole substrates Posaconazole and Voriconazole. Of six Clorgyline analogs, M19 and M25 were identified as potential sensitizers of azole resistance. M19 and M25 were found to act synergistically with azoles against resistant C. auris clade I isolates and recombinant Saccharomyces cerevisiae strains overexpressing C. auris efflux pumps. Nile Red assays with the recombinant strains showed M19 and M25 inhibited the activity of Cdr1 and Mdr1 efflux pumps that are known to play key roles in azole resistance in C. auris clades I, III, and IV. While Clorgyline, M19 and M25 uncoupled the Oligomycin-sensitive ATPase activity of Cdr1 from C. albicans and C. auris, their mode of action is yet to be fully elucidated. The experimental combinations described herein provides a starting point to combat azole resistance dominated by overexpression of CauCdr1 in C. auris clades I and IV and CauMdr1 in C. auris clade III. Full article

Triazole fungicides are widely used to treat fungal pathogens in field crops, but very few studies have investigated whether fields of these crops constitute hotspots of azole resistance in Aspergillus fumigatus. Soil samples were collected from 22 fields in two regions of eastern France and screened for triazole residues and azole-resistant A. fumigatus (ARAf). Real-time quantitative PCR (qPCR) was used to quantify A. fumigatus in these soil samples. All the plots contained tebuconazole at concentrations from 5.5 to 19.1 ng/g of soil, and 5 of the 22 plots also contained epoxiconazole. Only a few fungal isolates were obtained, and no ARAf was detected. A. fumigatus qPCR showed that this fungal species was, on average, 5000 times more common in soil from flowerbeds containing ARAf than in soil from field crops. Thus, field-crop soils do not appear to promote A. fumigatus development, even if treated with azole fungicides, and cannot be considered hotspots of resistance. Indeed, our results suggest that they are instead a coldspot of resistance and highlight how little is known about the ecological niche of this species. Full article

The rapid emergence of invasive fungal infections correlates with the increasing population of immunocompromised individuals, with many cases leading to death. The progressive increase in the incidence of Aspergillus isolates is even more severe due to the clinical challenges in treating invasive infections in immunocompromised patients with respiratory conditions. Rapid detection and diagnosis are needed to reduce mortality in individuals with invasive aspergillosis-related infections and thus efficient identification impacts clinical success. The phenotypic array method was compared to conventional morphology and molecular identification on thirty-six Aspergillus species isolated from patients with respiratory infections at the Inkosi Albert Luthuli Hospital in Kwa-Zulu Natal. In addition, an antimicrobial array was also carried out to screen for possible novel antimicrobial compounds for treatment. Although traditional morphological techniques are useful, genetic identification was the most reliable, assigning 26 to Aspergillus fumigatus species, 8 Aspergillus niger, and 2 Aspergillus flavus including cryptic species of A. niger, A. tubingensis and A. welwitschiae. The phenotypic array technique was only able to identify isolates up to the genus level due to a lack of adequate reference clinical species in the database. However, this technique proved crucial in assessing a wide range of possible antimicrobial options after these isolates exhibited some resistance to azoles. Antifungal profiles of the thirty-six isolates on the routine azole voriconazole showed a resistance of 6%, with 61% having moderate susceptibility. All isolates resistant to the salvage therapy drug, posaconazole pose a serious concern. Significantly, A. niger was the only species resistant (25%) to voriconazole and has recently been reported as the species isolated from patients with COVID-19-associated pulmonary aspergillosis (CAPA). Phenotypic microarray showed that 83% of the isolates were susceptible to the 24 new compounds and novel compounds were identified for potentially effective combination treatment of fungal infections. This study also reports the first TR34/98 mutation in Aspergillus clinical isolates which is located in the cyp51A gene. Full article

Azole resistance in Aspergillus fumigatus (AFM) is mainly associated with mutations in CYP51A and its promoter region or its homologue CYP51B. We evaluated the in vitro activity of isavuconazole, itraconazole, posaconazole, and voriconazole against 660 AFM collected during 2017–2020. Isolates were tested via CLSI broth microdilution. CLSI epidemiological cutoff values were applied. Non-wildtype (NWT) isolates to azoles were screened for alterations in the CYP51 sequences using whole genome sequencing. Azoles had similar activities against 660 AFM isolates. Overall, AFM displayed WT MIC values to isavuconazole (92.7%), itraconazole (92.9%), posaconazole (97.3%), and voriconazole (96.7%). Only 66 isolates (10.0%) were NWT to 1 or more of the azoles, and 32 harbored one or more alterations in the CYP51 sequences. Of these, 29/32 (90.1%) were NWT to itraconazole, 25/32 (78.1%) were NWT to isavuconazole, 17/32 (53.1%) were NWT to voriconazole, and 11/32 (34.4%) were NWT to posaconazole. The most frequent alteration was CYP51A TR34/L98H, carried by 14 isolates. Four isolates carried the alteration I242V in CYP51A, and G448S; A9T, or G138C was carried by one isolate each. Multiple alterations in CYP51A were detected in five isolates. Alterations in CYP51B were noted in seven isolates. Among 34 NWT isolates without -CYP51 alterations, WT rates to isavuconazole, itraconazole, voriconazole, and posaconazole were 32.4%, 47.1%, 85.3%, and 82.4%, respectively. Ten different CYP51 alterations were detected in 32/66 NWT isolates. Alterations in AFM CYP51 sequences can have variable effects on the in vitro activity of the azoles that are best delineated by testing all triazoles. Full article

Aspergillus fumigatus is the main causative agent of avian aspergillosis and results in significant health problems in birds, especially those living in captivity. The fungal contamination by A. fumigatus in the environment of Humboldt penguins (Spheniscus humboldti), located in a Belgian zoo, was assessed through the analysis of air, water, sand and nest samples during four non-consecutive days in 2021–2022. From these samples, potential azole-resistant A. fumigatus (ARAF) isolates were detected using a selective culture medium. A total of 28 veterinary isolates obtained after necropsy of Humboldt penguins and other avian species from the zoo were also included. All veterinary and suspected ARAF isolates from the environment were characterized for their azole-resistance profile by broth microdilution. Isolates displaying phenotypic resistance against at least one medical azole were systematically screened for mutations in the cyp51A gene. A total of 14 (13.6%) ARAF isolates were identified from the environment (n = 8) and from Humboldt penguins (n = 6). The TR34/L98H mutation was observed in all resistant environmental strains, and in two resistant veterinary strains. To the best of our knowledge, this is the first description of this mutation in A. fumigatus isolates from Humboldt penguins. During the period 2017–2022, pulmonary aspergillosis was confirmed in 51 necropsied penguins, which reflects a death rate due to aspergillosis of 68.0%, mostly affecting adults. Microsatellite polymorphism analysis revealed a high level of diversity among environmental and veterinary A. fumigatus isolates. However, a cluster was observed between one veterinary isolate and six environmental strains, all resistant to medical azoles. In conclusion, the environment of the Humboldt penguins is a potential contamination source of ARAF, making their management even more complex. Full article