Advances in Fusarium drug resistance research

Harnessing RNA interference for the control of Fusarium species: A critical review

Fusarium fungi are a pervasive threat to global agricultural productivity. They cause a spectrum of plant diseases that result in significant yield losses and threaten food safety by producing mycotoxins that are harmful to human and animal health. In recent years, the exploitation of the RNA interference (RNAi) mechanism has emerged as a promising avenue for the control of Fusarium-induced diseases, providing both a mechanistic understanding of Fusarium gene function and a potential strategy for environmentally sustainable disease management. However, despite significant progress in elucidating the presence and function of the RNAi pathway in different Fusarium species, a comprehensive understanding of its individual protein components and underlying silencing mechanisms remains elusive. Accordingly, while a considerable number of RNAi-based approaches to Fusarium control have been developed and many reports of RNAi applications in Fusarium control under laboratory conditions have been published, the applicability of this knowledge in agronomic settings remains an open question, and few convincing data on RNAi-based disease control under field conditions have been published. This review aims to consolidate the current knowledge on the role of RNAi in Fusarium disease control by evaluating current research and highlighting important avenues for future investigation.

Antarctic Streptomyces: Promising biocontrol agents for combating Fusarium oxysporum f. sp. cubense

Fusarium wilt of Banana (FWB) caused by Fusarium oxysporum f. sp. cubense (Foc) poses a significant threat to the banana industry, with current inadequate control measures. This study evaluated the antifungal potential of nine Streptomyces strains isolated from Antarctic soil samples, using Casein-Starch media to stimulate the production of antifungal compounds. The inhibition spectrum against Foc was assessed under laboratory conditions using the well diffusion on Mueller-Hinton agar, with antifungal activity measured in arbitrary units (AU/mL) and minimum inhibitory concentration (MIC) tested using ethyl acetate extracts. Among the nine isolates, K6 and E7 were closely related to Streptomyces polyrhachis and Streptomyces fildesensis, exhibited significant antifungal activity, with K6 and E7 showing 320 and 80 AU/mL, and MIC values of 250 and >500 ppm, respectively. These findings highlight K6 and E7 as potential biocontrol agents against Foc, offering new avenues for sustainable Fusarium wilt management in banana cultivation.

Disseminated fusariosis after allogenic hematopoietic stem cell transplantation: case report

In allogenic stem cell recipients, invasive fungal disease is a common yet dreaded complication with high mortality. Among these, fusariosis is especially complex to treat due to high intrinsic resistance and few antimycotic options, requiring close cooperation of all involved departments. We here report an instructive case of disseminated fusariosis after allogenic stem cell transplantation with fatal outcome despite maximum treatment.

Breaking Down the Barriers of Drug Resistance and Corneal Permeability with Chitosan-Poly(ethylene glycol)-LK13 Peptide Conjugate to Combat Fungal Keratitis

Fungal keratitis (FK) is a leading cause of preventable blindness and eye loss. The poor antifungal activity, increased drug resistance, limited corneal permeability, and unsatisfactory biosafety of conventional antifungal eye drops are among the majority of the challenges that need to be addressed for currently available antifungal drugs. Herein, this study proposes an effective strategy that employs chitosan-poly(ethylene glycol)-LK13 peptide conjugate (CPL) in the treatment of FK. Nanoassembly CPL can permeate the lipophilic corneal epithelium in the transcellular route, and its hydrophilicity surface is a feature to drive its permeability through hydrophilic stroma. When encountering fungal cell membrane, CPL dissembles and exposes the antimicrobial peptide (LK13) to destroy fungal cell membranes, the minimum inhibitory concentration values of CPL against Fusarium solani (F. solani) are always not to exceed 8 μg peptide/mL before and after drug resistance induction. In a rat model of Fusarium keratitis, CPL demonstrates superior therapeutic efficacy than commercially available natamycin ophthalmic suspension. This study provides more theoretical and experimental supports for the application of CPL in the treatment of FK.

ResFungi: A Novel Protein Database of Antifungal Drug Resistance Genes Using a Hidden Markov Model Profile

Fungal infections vary from superficial to invasive and can be life-threatening in immunocompromised and healthy individuals. Antifungal resistance is one of the main reasons for an increasing concern about fungal infections as they become more complex and harder to treat. The fungal "omics" databases help us find drug resistance genes, which is of great importance and extremely necessary. With that in mind, we built a new platform for drug resistance genes. We added seven drug classes of resistance genes to our database: azoles (without specifying which drug), fluconazole, voriconazole, itraconazole, flucytosine, micafungin, and caspofungin. Species with known resistance genes were used to validate the results from our database. This study describes a list of 261 candidate genes related to antifungal resistance, with several genes displaying transport functions involved in azole resistance. Over 65% of the candidate genes found were related to at least one type of azole. Overall, the candidate genes found have functional annotations consistent with genes or enzymes that have been linked to antifungal resistance in previous studies. Also, candidate antifungal resistance genes found exhibit functional annotations consistent with previously described resistance mechanisms. The existence of an HMM profile focusing on antifungal resistance genes allows in silico searches for candidate genes, helping future wet lab experiments, and hence, reducing costs when studying candidate antifungal genes without prior knowledge of the species or genes. Finally, ResFungi has proven to be a powerful tool to narrow down candidate antifungal-related genes and unravel mechanisms related to resistance to help in the design of experiments focusing on the genetic basis of antifungal resistance.

Cutaneous fusarium disease and leukaemias: A systematic review

The present study analyses the clinical characteristics of patients diagnosed with cutaneous fusarium through a systematic review of cases reported in literature. A total of 39 cases were included, of which 53% were men, 30% were women, and in 17% the sex was not specified. The age ranged from 5 to 85 years. Most cases were reported in Brazil, followed by Japan and United States of America. The most common agent was Fusarium solani, in 37.5% of the patients. Most of the affected individuals had acute myeloid leukaemia and some of the predisposing factors, which included induction chemotherapy, febrile neutropenia, and bone marrow transplantation. The clinical topography of the lesions was located in 27.5% and disseminated in 72.5%, with the most observed clinical feature outstanding the presence of papules and nodules with central necrosis in 47% of the cases. Longer survival was demonstrated in those treated with more than three antifungals. It is concluded that cutaneous fusarium is a complex and challenging clinical entity, infection in patients with leukaemias underscores the need for thorough care to decrease morbidity and mortality.

Fusarium species,Scedosporium species, and Lomentospora prolificans: A systematic review to inform the World Health Organization priority list of fungal pathogens

Recognizing the growing global burden of fungal infections, the World Health Organization established a process to develop a priority list of fungal pathogens (FPPL). In this systematic review, we aimed to evaluate the epidemiology and impact of infections caused by Fusarium spp., Scedosporium spp., and Lomentospora prolificans to inform the first FPPL. PubMed and Web of Sciences databases were searched to identify studies published between January 1, 2011 and February 23, 2021, reporting on mortality, complications and sequelae, antifungal susceptibility, preventability, annual incidence, and trends. Overall, 20, 11, and 9 articles were included for Fusarium spp., Scedosporium spp., and L. prolificans, respectively. Mortality rates were high in those with invasive fusariosis, scedosporiosis, and lomentosporiosis (42.9%-66.7%, 42.4%-46.9%, and 50.0%-71.4%, respectively). Antifungal susceptibility data, based on small isolate numbers, showed high minimum inhibitory concentrations (MIC)/minimum effective concentrations for most currently available antifungal agents. The median/mode MIC for itraconazole and isavuconazole were ≥16 mg/l for all three pathogens. Based on limited data, these fungi are emerging. Invasive fusariosis increased from 0.08 cases/100 000 admissions to 0.22 cases/100 000 admissions over the time periods of 2000-2009 and 2010-2015, respectively, and in lung transplant recipients, Scedosporium spp. and L. prolificans were only detected from 2014 onwards. Global surveillance to better delineate antifungal susceptibility, risk factors, sequelae, and outcomes is required.

Onychomycosis due to Fusarium species in different continents, literature review on diagnosis and treatment

Fusarium species are an emerging cause of onychomycosis, and the number of cases has dramatically increased in recent decades worldwide. This review presents an overview of the onychomycosis cases caused by Fusarium species and diagnosis and treatment that have been reported in the literature. The most common causative agent of onychomycosis is F. solani species complex, which accounts for 11.68% of the cases of Fusarium onychomycosis, followed by the F. oxysporum species complex (164 out of 1669), which is accounted for 9.83% of the total. F. fujikuroi species complex (42 out of 1669) and F. dimerum species complex (7 out of 1669) are responsible for 2.52% and 0.42 cases, respectively. Fusarium nail infections were reported in patients aged range 1-98, accounting for 5.55% (1669 out of 30082) of all cases. Asia has the highest species diversity of Fusarium onychomycosis (31.51%). South America accounts for 21.09%, and the most common causative agent is F. solani (19.32%), followed by F. oxysporum species complex (15.63%). Europe accounts for 4.90% of cases caused by F. oxysporum, followed by F. solani. Africa accounts for 23.87% of the cases due to the F. solani species complex, followed by F. oxysporum and F. fujikuroi. Distal and lateral subungual onychomycosis was the most common clinical symptom accounting for 58.7% (135 out of 230) of the cases. Data analysis relieved that terbinafine and itraconazole are active treatments for Fusarium onychomycosis. For a definitive diagnosis, combining of direct examination, culture and sequencing of the elongation factor of translation 1α are recommended. Accurate identification of the causative agents of onychomycosis due to Fusarium species and antifungal susceptibility testing is essential in patient management.

Light-Driven Tetra- and Octa-β-substituted Cationic Zinc(II) Phthalocyanines for Eradicating Fusarium oxysporum Conidia

Photodynamic inactivation (PDI) is an emerging therapeutic approach that can effectively inactivate diverse microbial forms, including vegetative forms and spores, while preserving host tissues and avoiding the development of resistance to the photosensitization procedure. This study evaluates the antifungal and sporicidal photodynamic activity of two water-soluble amphiphilic tetra- and octa-β-substituted zinc(II) phthalocyanine (ZnPc) dyes with dimethylaminopyridinium groups at the periphery (ZnPcs 1, 2) and their quaternized derivatives (ZnPcs 1a, 2a). Tetra(1, 1a)- and octa(2, 2a)-β-substituted zinc(II) phthalocyanines were prepared and assessed as photosensitizers (PSs) for their effects on Fusarium oxysporum conidia. Antimicrobial photoinactivation experiments were performed with each PS at 0.1, 1, 10, and 20 µM under white light irradiation at an irradiance of 135 mW·cm-2, for 60 min (light dose of 486 J·cm-2). High PDI efficiency was observed for PSs 1a, 2, and 2a (10 µM), corresponding to inactivation until the method's detection limit. PS 1 (20 µM) also achieved a considerable reduction of >5 log10 in the concentration of viable conidia. The quaternized PSs (1a, 2a) showed better PDI performance than the non-quaternized ones (1, 2), even at the low concentration of 1 µM, and a light dose of 486 J·cm-2. These cationic phthalocyanines are potent photodynamic drugs for antifungal applications due to their ability to effectively inactivate resistant forms, like conidia, with low concentrations and reasonable energy doses.

Lipopeptides from an isolate of Bacillus subtilis complex have inhibitory and antibiofilm effects on Fusarium solani

Bacillus subtilis species complex is known as lipopeptide-producer with biotechnological potential for pharmaceutical developments. This study aimed to identify lipopeptides from a bacterial isolate and evaluate their antifungal effects. Here, we isolated and identified a lipopeptide-producing bacterium as a species of Bacillus subtilis complex (strain UL-1). Twenty lipopeptides (six iturins, six fengycins, and eight surfactins) were identified in the crude extract (CE) and fractions (F1, F2, F3, and F4), and the highest content of total lipopeptides was observed in CE and F2. The chemical quantification data corroborate with the hemolytic and antifungal activities that CE and F2 were the most hemolytic and inhibited the fungal growth at lower concentrations against Fusarium spp. In addition, they caused morphological changes such as shortening and/or atypical branching of hyphae and induction of chlamydospore-like structure formation, especially in Fusarium solani. CE was the most effective in inhibiting the biofilm formation and in disrupting the mature biofilm of F. solani reducing the total biomass and the metabolic activity at concentrations ≥ 2 µg/mL. Moreover, CE significantly inhibited the adherence of F. solani conidia on contact lenses and nails as well as disrupted the pre-formed biofilms on nails. CE at 100 mg/kg was nontoxic on Galleria mellonella larvae, and it reduced the fungal burden in larvae previously infected by F. solani. Taken together, the lipopeptides obtained from strain UL-1 demonstrated a potent anti-Fusarium effect inducing morphological alterations and antibiofilm activities. Our data open further studies for the biotechnological application of these lipopeptides as potential antifungal agents. KEY POINTS: • Lipopeptides inhibit Fusarium growth and induce chlamydospore-like structures. • Lipopeptides hamper the adherence of conidia and biofilms of Fusarium solani. • Iturins, fengycins, and surfactins were associated with antifungal effects.

Studies on Antifungal Properties of Methacrylamido Propyl Trimethyl Ammonium Chloride Polycations and Their Toxicity In Vitro

The biological activity of polycations is usually associated with their biocidal properties. Their antibacterial features are well known, but in this work, observations on the antifungal properties of macromolecules obtained by methacrylamido propyl trimethyl ammonium chloride (MAPTAC) polymerization are presented. The results, not previously reported, make it possible to correlate antifungal properties directly with the structure of the macromolecule, in particular the molecular mass. The polymers described here have antifungal activity against some filamentous fungi. The strongest effect occurs for polymers with a mass of about 0.5 mDa which have confirmed activity against the multidrug-resistant species Scopulariopsis brevicaulis, Fusarium oxysporum, and Fusarium solani, as well as the dermatophytes Trichophyton mentagrophytes, Trichophyton rubrum, Trichophyton interdigitale, and Trichophyton tonsurans. In addition, this publication describes the effects of these macromolecular systems on serum and blood components and provides a preliminary assessment of toxicity on cell lines of skin-forming cells, i.e., fibroblasts and keratinocytes. Additionally, using a Franz diffusion chamber, a negligibly low transport of the active polymer through the skin was demonstrated, which is a desirable effect for externally applied antifungal drugs. IMPORTANCE Infectious diseases are a very big medical, social, and economic problem. Even before the COVID-19 pandemic, certain infections were among of the most common causes of death. The difficulties in the treatment of infectious diseases concern in particular fungal diseases, against which we have only a few classes of drugs represented by a few substances. The publication presents the preliminary results of the in vitro antifungal activity studies of four MAPTAC polymers on different fungal species and their cytotoxicity to human cells (fibroblasts and keratinocytes). The paper also compares these properties with analogous ones of two commonly used antifungal drugs, ciclopirox and terbinafine.

Endophthalmitis as the initial manifestation of invasive fusariosis in an allogeneic stem cell transplant patient: A case report

Fusarium species manifests as an opportunistic infection with intrinsic resistance to most antifungals. We present a case of a 63-year-old male with myelodysplasia who received allogeneic stem cell transplantation and presented with endophthalmitis as the initial manifestation of invasive fusariosis that progressed to a fatal outcome despite combined intravitreal and systemic antifungal therapies. We urge clinicians to consider this complication of fusarium infection especially with the widespread use of antifungal prophylaxis that may incur selection of more resistant, invasive fungal species.

Antifungal activity against Fusarium oxysporum of quinolizidines isolated from three controlled-growth Genisteae plants: structure-activity relationship implications

The Genisteae tribe belongs to the Fabaceae family. The wide occurrence of secondary metabolites, explicitly highlighting the quinolizidine alkaloids (QAs), characterizes this tribe. In the present study, twenty QAs (1-20), including lupanine (1-7), sparteine (8-10), lupanine (11), cytisine and tetrahydrocytisine (12-17), and matrine (18-20)-type QAs were extracted and isolated from leaves of three species (i.e., Lupinus polyphyllus ('rusell' hybrid), Lupinus mutabilis, and Genista monspessulana) belonging to the Genisteae tribe. These plant sources were propagated under greenhouse conditions. The isolated compounds were elucidated by analyzing their spectroscopical data (MS, NMR). The antifungal effect on the mycelial growth of Fusarium oxysporum (Fox) of each isolated QA was then evaluated through the amended medium assay. The best antifungal activity was found to be for compounds 8 (IC₅₀ = 16.5 µM), 9 (IC₅₀ = 7.2 µM), 12 (IC₅₀ = 11.3 µM), and 18 (IC₅₀ = 12.3 µM). The inhibitory data suggest that some QAs could efficiently inhibit Fox mycelium growth depending on particular structural requirements deduced from structure-activity relationship scrutinies. The identified quinolizidine-related moieties can be involved in lead structures to develop further antifungal bioactives against Fox.

Mucorales/Fusarium Mixed Infection in Hematologic Patient with COVID-19 Complications: An Unfortunate Combination

Hematological diseases, especially those causing severe neutropenia, represent the main factor in the development of invasive fungal infections (IFIs). Furthermore, COVID-19 has been considerably associated with IFIs due to immunological dysregulation, prolonged hospitalization in intensive care units, and immunomodulatory therapies. Opportunistic molds are correlated with elevated morbidity and mortality rates in these patients, due to immune impairment, diagnostic complexity, and therapeutic challenges. Among opportunistic fungal infections, the Mucorales and Fusarium species are considered particularly aggressive, especially during severe neutropenia. A mixed Mucorales/Fusarium infection has been rarely described in scientific literature. Herein, we report a case of Mucorales and Fusarium co-infection in a patient with acute leukemia whose clinical history was also complicated by COVID-19. Herein, we report a challenging case in order to encourage the clinical suspicion of combined fungal infections in immunosuppressed patients, performing a punctual microbiological diagnosis, and promptly administering the correct empiric and targeted antifungal therapy.

Intravenous Fosfomycin: A Potential Good Partner for Cefiderocol. Clinical Experience and Considerations

Multidrug resistant Gram-negative bacteremia represents a therapeutic challenge clinicians have to deal with. This concern becomes more difficult when causing germs are represented by carbapenem resistant Acinetobacter baumannii or difficult-to-treat Pseudomonas aeruginosa. Few antibiotics are available against these cumbersome bacteria, although literature data are not conclusive, especially for Acinetobacter. Cefiderocol could represent a valid antibiotic choice, being a molecule with an innovative mechanism of action capable of overcoming common resistance pathways, whereas intravenous fosfomycin may be an appropriate partner either enhancing cefiderocol activity or avoiding resistance development. Here we report two patients with MDR Gram negative bacteremia who were successfully treated with a cefiderocol/fosfomycin combination.

Preliminary Studies on the Mechanism of Antifungal Activity of New Cationic β-Glucan Derivatives Obtained from Oats and Barley

New chemical structures with antifungal properties are highly desirable from the point of view of modern pharmaceutical science, especially due to the increasingly widespread instances of drug resistance in the case of these diseases. One way to solve this problem is to use polymeric drugs, widely described as biocidal, positively charged macromolecules. In this work, we present the synthesis of new cationic β-glucan derivatives that show selective antifungal activity and at the same time low toxicity toward animal and human cells. Two β-glucans isolated from oats and barley and modified using glycidyltrimethylammonium chloride were obtained and evaluated for biocidal properties on the cells of mammals and pathogenic fungi and bacteria. These compounds were found to be nontoxic to fibroblast and bacterial cells but showed selective toxicity to certain species of filamentous fungi (Scopulariopsis brevicaulis) and yeasts (Cryptococcus neoformans). The most important aspect of this work is the attempt to explain the mechanisms of action of these compounds by studying their interaction with biological membranes. This was achieved by examining the interactions with model biological membranes representative of given families of microorganisms using Langmuir monolayers. The data obtained partly show correlations between the results for model systems and biological experiments and allow indicating that the selective antifungal activity of cationic β-glucans is related to their interaction with fungal biological membranes and partly lack of such interaction toward cells of other organisms. In addition, the obtained macromolecules were characterized by spectral methods (Fourier transform infrared (FTIR) and ¹H nuclear magnetic resonance (NMR) spectroscopies) to confirm that the desired structure was obtained, and their degree of modification and molecular weights were determined.

Seaweed-Derived Phenolic Compounds in Growth Promotion and Stress Alleviation in Plants

Abiotic and biotic stress factors negatively influence the growth, yield, and nutritional value of economically important food and feed crops. These climate-change-induced stress factors, together with the ever-growing human population, compromise sustainable food security for all consumers across the world. Agrochemicals are widely used to increase crop yield by improving plant growth and enhancing their tolerance to stress factors; however, there has been a shift towards natural compounds in recent years due to the detrimental effect associated with these agrochemicals on crops and the ecosystem. In view of these, the use of phenolic biostimulants as opposed to artificial fertilizers has gained significant momentum in crop production. Seaweeds are marine organisms and excellent sources of natural phenolic compounds that are useful for downstream agricultural applications such as promoting plant growth and improving resilience against various stress conditions. In this review, we highlight the different phenolic compounds present in seaweed, compare their extraction methods, and describe their downstream applications in agriculture.

Comparison of molecular and MALDI-TOF MS identification and antifungal susceptibility of clinical Fusarium isolates in Southern China

BACKGROUND

Fusarium species are opportunistic causative agents of superficial and disseminated human infections. Fast and accurate identification and targeted antifungal therapy give help to improve the patients' prognosis.

OBJECTIVES

This study aimed to evaluate the effectiveness of matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS) for Fusarium identification, and investigate the epidemiology and antifungal susceptibility profiles of clinical Fusarium isolates in Southern China.

METHODS

There were 95 clinical Fusarium isolates identified by DNA sequencing of translation elongation factor 1-alpha (TEF1α) and MALDI-TOF MS, respectively. Antifungal susceptibility testing of isolates was performed by broth microdilution according to the CLSI approved standard M38-A3 document.

RESULTS

Seven species complexes (SC) with 17 Fusarium species were identified. The most prevalent SC was the F. solani SC (70.5%, 67/95), followed by the F. fujikuroi SC (16.8%, 16/95). F. keratoplasticum within the F. solani SC was the most prevalent species (32.6%, 31/95). There were 91.6% (87/95) of isolates identified by MALDI-TOF MS at the SC level. In most of species, amphotericin B and voriconazole showed lower MICs compared to itraconazole and terbinafine. The F. solani SC showed higher MICs to these antifungal agents compared to the other SCs. There were 10.5% (10/95) of strains with high MICs for amphotericin B (≥8 μg/ml), terbinafine (≥32 μg/ml) and itraconazole (≥32 μg/ml) simultaneously, mostly focusing on F. keratoplasticum (9/10).

CONCLUSION

MALDI-TOF MS exhibited good performance on the identification of Fusarium strains at the SC level. The F. solani SC was the most prevalent clinical SC in Southern China. The MICs varied significantly among different species or SCs to different antifungal agents.

CYP51 Mutations in the Fusarium solani Species Complex: First Clue to Understand the Low Susceptibility to Azoles of the Genus Fusarium

Members of Fusarium solani species complex (FSSC) are cosmopolitan filamentous fungi responsible for invasive fungal infections in immunocompromised patients. Despite the treatment recommendations, many strains show reduced sensitivity to voriconazole. The objective of this work was to investigate the potential relationship between azole susceptibility and mutations in CYP51 protein sequences. Minimal inhibitory concentrations (MICs) for azole antifungals have been determined using the CLSI (Clinical and Laboratory Standards Institute) microdilution method on a panel of clinical and environmental strains. CYP51A, CYP51B and CYP51C genes for each strain have been sequenced using the Sanger method. Amino acid substitutions described in multiple azole-resistant Aspergillus fumigatus (mtrAf) strains have been sought and compared with other Fusarium complexes’ strains. Our results show that FSSC exhibit point mutations similar to those described in mtrAf. Protein sequence alignments of CYP51A, CYP51B and CYP51C have highlighted different profiles based on sequence similarity. A link between voriconazole MICs and protein sequences was observed, suggesting that these mutations could be an explanation for the intrinsic azole resistance in the genus Fusarium. Thus, this innovative approach provided clues to understand low azole susceptibility in FSSC and may contribute to improving the treatment of FSSC infection.

Identification of Antifungal Compounds from Piper Plants Against Fusarium oxysporum: An Untargeted Metabolite Profiling-Based Approach

The phytopathogen Fusarium oxysporum produces considerable losses in economically important crops, making alternative control measures urgently required. Piper plants are widely distributed in tropical regions, and they are also known to produce metabolites with biological activity against infectious agents. As part of our continuous search for antifungals, 18 Piper-derived ethanolic extracts were evaluated by their in vitro effect on F oxysporum mycelial growth inhibition. The total content of phenol and flavonoid measurements and liquid chromatography-electrospray ionization-mass spectrometry analysis served as the chemical characterization of the investigated extracts. Piper pulchrum, Piper barcoense, and Piper tuberculatum exhibited the highest mycelial growth inhibition (>74%). The integration of chemical fingerprints and bioactivity datasets led to recognizing 4 bioactive candidates among extracts through single- Y orthogonal partial least squares regression and univariate statistics. These candidates were 2 amides (1,3), an alkyl lactone (2), and a prenylated benzoquinone (4), subsequently isolated and identified by nuclear magnetic resonance spectroscopy. These isolated compounds exhibited reasonable antifungal activity (IC50 < 50 µM). The findings indicated that the correlative association is advantageous for identifying bioactive metabolites within active extracts.

Draft genome sequence of a lipopeptide-producing Bacillus amyloliquefaciens strain isolated from wheat field soil with antagonistic activity against azole-resistant Fusarium graminearum

OBJECTIVES

Lipopeptides have been revealed as good potential biocontrol agents against various pathogenic microbes. In the present work, we report the draft genome sequence of a lipopeptide-producing strain of Bacillus amyloliquefaciens (7D3) that showed good antifungal activity against the azole-resistant pathogenic fungus Fusarium graminearum.

METHODS

Whole-genome sequencing of strain 7D3 was performed on an Illumina MiSeq 300 platform. Raw data were cleaned using Trim Galore v.0.4.0 and were checked for quality using FastQC. De novo assembly was performed using the SOAPdenovo2 package. Genes responsible for the biosynthesis of secondary metabolites were identified using antiSMASH.

RESULTS

Bacillus amyloliquefaciens 7D3 genome assembly resulted in a total genome size of 3 913 220 bp with a G+C content of 46.13%. There were 3998 predicted genes with 72 tRNAs and 9 rRNAs. A total of ten gene clusters were found to be related to secondary metabolite biosynthesis, of which five were identified as lipopeptide synthesis clusters.

CONCLUSION

This study presents the genome sequence of B. amyloliquefaciens 7D3, which exhibited intense antagonistic activity against azole-resistant fungi. The whole genome sequence will help in the search for novel antifungal peptides against drug-resistant pathogens.

Medicines for Malaria Venture COVID Box: a source for repurposing drugs with antifungal activity against human pathogenic fungi

BACKGROUND

Treatment of mycoses is often ineffective, usually prolonged, and has some side effects. These facts highlight the importance of discovering new molecules to treat fungal infections.

OBJECTIVES

To search the Medicines for Malaria Venture COVID Box for drugs with antifungal activity.

METHODS

Fourteen human pathogenic fungi were tested against the 160 drugs of this collection at 1.0 µM concentration. We evaluated the ability of the drugs to impair fungal growth, their fungicidal nature, and morphological changes caused to cells.

FINDINGS

Thirty-four molecules (21.25%) presented antifungal activity. Seven are antifungal drugs and one is the agricultural fungicide cycloheximide. The other drugs with antifungal activity included antibiotics (n = 3), antimalarials (n = 4), antivirals (n = 2), antiparasitcs (n = 3), antitumor agents (n = 5), nervous system agents (n = 3), immunosuppressants (n = 3), antivomiting (n = 1), antiasthmatic (n = 1), and a genetic disorder agent (n = 1). Several of these drugs inhibited Histoplasma capsulatum and Paracoccidioides brasiliensis growth (15 and 20, respectively), while Fusarium solani was not affected by the drugs tested. Most drugs were fungistatic, but niclosamide presented fungicidal activity against the three dimorphic fungi tested. Cyclosporine affected morphology of Cryptococcus neoformans.

MAIN CONCLUSIONS

These drugs represent new alternatives to the development of more accessible and effective therapies to treat human fungal infections.

Contribution of NADPH-cytochrome P450 Reductase to Azole Resistance in Fusarium oxysporum

Fusarium species exhibit significant intrinsic resistance to most antifungal agents and fungicides, resulting in high mortality rates among immunocompromised patients. Consequently, a thorough characterization of the antifungal resistance mechanism is required for effective treatments and for preventing fungal infections and reducing antifungal resistance. In this study, an isolate of Fusarium oxysporum (wild-type) with broadly resistant to commonly antifungal agents was used to generate 1,450 T-DNA random insertion mutants via Agrobacterium tumefaciens-mediated transformation. Antifungal susceptibility test results revealed one mutant with increased sensitivity to azoles. Compared with the resistant wild-type, the mutant exhibited low MICs to KTZ, ITC, VRC, POS, and PCZ (0.125, 1, 0.06, 0.5, and 0.125μg/ml, respectively). The T-DNA insertion site of this mutant was characterized as involving two adjacent genes, one encoding a hypothetical protein with unknown function and the other encoding the NADPH-cytochrome P450 reductase, referred as CPR1. To confirm the involvement of these genes in the altered azole susceptibility, the independent deletion mutants were generated and the Cpr1 deletion mutant displayed the same phenotypes as the T-DNA random mutant. The deletion of Cpr1 significantly decreased ergosterol levels. Additionally, the expression of the downstream Cyp51 gene was affected, which likely contributed to the observed increased susceptibility to azoles. These findings verified the association between Cpr1 and azole susceptibility in F. oxysporum. Furthermore, this gene may be targeted to improve antifungal treatments.