Journal of Fungi

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17 pages, 1904 KiB

Open AccessArticle

Molecular Evaluation of the mRNA Expression of the ERG11, ERG3, CgCDR1, and CgSNQ2 Genes Linked to Fluconazole Resistance in Candida glabrata in a Colombian Population

by Leidy Yurany Cárdenas Parra, Ana Elisa Rojas Rodríguez, Jorge Enrique Pérez Cárdenas and Juan Manuel Pérez-Agudelo

J. Fungi 2024, 10(7), 509; https://doi.org/10.3390/jof10070509 - 22 Jul 2024

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Abstract

Introduction: The study of Candida glabrata genes associated with fluconazole resistance, from a molecular perspective, increases the understanding of the phenomenon with a view to its clinical applicability. Objective: We sought to establish the predictive molecular profile of fluconazole resistance in Candida glabrata [...] Read more.

Introduction: The study of Candida glabrata genes associated with fluconazole resistance, from a molecular perspective, increases the understanding of the phenomenon with a view to its clinical applicability. Objective: We sought to establish the predictive molecular profile of fluconazole resistance in Candida glabrata by analyzing the ERG11, ERG3, CgCDR1, and CgSNQ2 genes. Method: Expression was quantified using RT-qPCR. Metrics were obtained through molecular docking and Fisher discriminant functions. Additionally, a predictive classification was made against the susceptibility of C. glabrata to fluconazole. Results: The relative expression of the ERG3, CgCDR1, and CgSNQ2 genes was higher in the fluconazole-resistant strains than in the fluconazole-susceptible, dose-dependent strains. The gene with the highest relative expression in the fluconazole-exposed strains was CgCDR1, and in both the resistant and susceptible, dose-dependent strains exposed to fluconazole, this was also the case. The molecular docking model generated a median number of contacts between fluconazole and ERG11 that was lower than the median number of contacts between fluconazole and ERG3, -CgCDR1, and -CgSNQ2. The predicted classification through the multivariate model for fluconazole susceptibility achieved an accuracy of 73.5%. Conclusion: The resistant strains had significant expression levels of genes encoding efflux pumps and the ERG3 gene. Molecular analysis makes the identification of a low affinity between fluconazole and its pharmacological target possible, which may explain the lower intrinsic susceptibility of the fungus to fluconazole. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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13 pages, 2599 KiB

Open AccessArticle

Comparative Genomics of the First Resistant Candida auris Strain Isolated in Mexico: Phylogenomic and Pan-Genomic Analysis and Mutations Associated with Antifungal Resistance

by Arturo Casimiro-Ramos, Celia Bautista-Crescencio, Alvaro Vidal-Montiel, Gloria M. González, Juan Alfredo Hernández-García, César Hernández-Rodríguez and Lourdes Villa-Tanaca

J. Fungi 2024, 10(6), 392; https://doi.org/10.3390/jof10060392 - 30 May 2024

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Abstract

Candida auris is an emerging multidrug-resistant and opportunistic pathogenic yeast. Whole-genome sequencing analysis has defined five major clades, each from a distinct geographic region. The current study aimed to examine the genome of the C. auris 20–1498 strain, which is the first isolate [...] Read more.

Candida auris is an emerging multidrug-resistant and opportunistic pathogenic yeast. Whole-genome sequencing analysis has defined five major clades, each from a distinct geographic region. The current study aimed to examine the genome of the C. auris 20–1498 strain, which is the first isolate of this fungus identified in Mexico. Based on whole-genome sequencing, the draft genome was found to contain 70 contigs. It had a total genome size of 12.86 Mbp, an N50 value of 1.6 Mbp, and an average guanine-cytosine (GC) content of 45.5%. Genome annotation revealed a total of 5432 genes encoding 5515 proteins. According to the genomic analysis, the C. auris 20–1498 strain belongs to clade IV (containing strains endemic to South America). Of the two genes (ERG11 and FKS1) associated with drug resistance in C. auris, a mutation was detected in K143R, a gene located in a mutation hotspot of ERG11 (lanosterol 14-α-demethylase), an antifungal drug target. The focus on whole-genome sequencing and the identification of mutations linked to the drug resistance of fungi could lead to the discovery of new therapeutic targets and new antifungal compounds. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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15 pages, 3092 KiB

Open AccessArticle

Importance of the Aspergillus fumigatus Mismatch Repair Protein Msh6 in Antifungal Resistance Development

by Jose Lucio, Irene Gonzalez-Jimenez, Alejandra Roldan, Jorge Amich, Laura Alcazar-Fuoli and Emilia Mellado

J. Fungi 2024, 10(3), 210; https://doi.org/10.3390/jof10030210 - 12 Mar 2024

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Abstract

One of the systems responsible for the recognition and repair of mistakes occurring during cell replication is the DNA mismatch repair (MMR) system. Two major protein complexes constitute the MMR pathway: MutS and MutL. Here, we investigated the possible relation of four A. [...] Read more.

One of the systems responsible for the recognition and repair of mistakes occurring during cell replication is the DNA mismatch repair (MMR) system. Two major protein complexes constitute the MMR pathway: MutS and MutL. Here, we investigated the possible relation of four A. fumigatus MMR genes (msh2, msh6, pms1, and mlh1) with the development of azole resistance related to the phenomenon of multi-drug resistance. We examined the MMR gene variations in 163 Aspergillus fumigatus genomes. Our analysis showed that genes msh2, pms1, and mlh1 have low genetic variability and do not seem to correlate with drug resistance. In contrast, there is a nonsynonymous mutation (G240A) in the msh6 gene that is harbored by 42% of the strains, most of them also harboring the TR₃₄/L98H azole resistance mechanism in cyp51A. The msh6 gene was deleted in the akuB^KU80 A. fumigatus strain, and the ∆msh6 isolates were analyzed for fitness, azole susceptibility, and virulence capacity, showing no differences compared with the akuB^KU80 parental strain. Wild-type msh6 and Δmsh6 strains were grown on high concentrations of azole and other non-azole fungicides used in crop protection. A 10- and 2-fold higher mutation frequency in genes that confer resistance to boscalid and benomyl, respectively, were observed in Δmsh6 strains compared to the wild-type. This study suggests a link between Msh6 and fungicide resistance acquisition. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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18 pages, 4241 KiB

Open AccessArticle

Miltefosine: A Repurposing Drug against Mucorales Pathogens

by Mariana Ingrid Dutra da Silva Xisto, Rodrigo Rollin-Pinheiro, Victor Pereira Rochetti, Yuri de Castro-Almeida, Luana Pereira Borba-Santos, Giulia Maria Pires dos Santos-Freitas, Jefferson Cypriano, Fernanda de Ávila Abreu, Sonia Rozental and Eliana Barreto-Bergter

J. Fungi 2023, 9(12), 1166; https://doi.org/10.3390/jof9121166 - 4 Dec 2023

Cited by 2 | Viewed by 1373

Abstract

Mucorales are a group of non-septated filamentous fungi widely distributed in nature, frequently associated with human infections, and are intrinsically resistant to many antifungal drugs. For these reasons, there is an urgent need to improve the clinical management of mucormycosis. Miltefosine, which is [...] Read more.

Mucorales are a group of non-septated filamentous fungi widely distributed in nature, frequently associated with human infections, and are intrinsically resistant to many antifungal drugs. For these reasons, there is an urgent need to improve the clinical management of mucormycosis. Miltefosine, which is a phospholipid analogue of alkylphosphocholine, has been considered a promising repurposing drug to be used to treat fungal infections. In the present study, miltefosine displayed antifungal activity against a variety of Mucorales species, and it was also active against biofilms formed by these fungi. Treatment with miltefosine revealed modifications of cell wall components, neutral lipids, mitochondrial membrane potential, cell morphology, and the induction of oxidative stress. Treated Mucorales cells also presented an increased susceptibility to SDS. Purified ergosterol and glucosylceramide added to the culture medium increased miltefosine MIC, suggesting its interaction with fungal lipids. These data contribute to elucidating the effect of a promising drug repurposed to act against some relevant fungal pathogens that significantly impact public health. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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16 pages, 2729 KiB

Open AccessArticle

Structural and Functional Alterations Caused by Aureobasidin A in Clinical Resistant Strains of Candida spp.

by Rodrigo Rollin-Pinheiro, Daniel Clemente de Moraes, Brayan Bayona-Pacheco, Jose Alexandre da Rocha Curvelo, Giulia Maria Pires dos Santos-Freitas, Mariana Ingrid Dutra da Silva Xisto, Luana Pereira Borba-Santos, Sonia Rozental, Antonio Ferreira-Pereira and Eliana Barreto-Bergter

J. Fungi 2023, 9(11), 1115; https://doi.org/10.3390/jof9111115 - 17 Nov 2023

Cited by 1 | Viewed by 1089

Abstract

Candida species are one of the most concerning causative agents of fungal infections in humans. The treatment of invasive Candida infections is based on the use of fluconazole, but the emergence of resistant isolates has been an increasing concern which has led to [...] Read more.

Candida species are one of the most concerning causative agents of fungal infections in humans. The treatment of invasive Candida infections is based on the use of fluconazole, but the emergence of resistant isolates has been an increasing concern which has led to the study of alternative drugs with antifungal activity. Sphingolipids have been considered a promising target due to their roles in fungal growth and virulence. Inhibitors of the sphingolipid biosynthetic pathway have been described to display antifungal properties, such as myriocin and aureobasidin A, which are active against resistant Candida isolates. In the present study, aureobasidin A did not display antibiofilm activity nor synergism with amphotericin B, but its combination with fluconazole was effective against Candida biofilms and protected the host in an in vivo infection model. Alterations in treated cells revealed increased oxidative stress, reduced mitochondrial membrane potential and chitin content, as well as altered morphology, enhanced DNA leakage and a greater susceptibility to sodium dodecyl sulphate (SDS). In addition, it seems to inhibit the efflux pump CaCdr2p. All these data contribute to elucidating the role of aureobasidin A on fungal cells, especially evidencing its promising use in clinical resistant isolates of Candida species. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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29 pages, 7277 KiB

Open AccessArticle

The Transcriptome Response to Azole Compounds in Aspergillus fumigatus Shows Differential Gene Expression across Pathways Essential for Azole Resistance and Cell Survival

by Margriet W. J. Hokken, Jordy P. M. Coolen, Hilbert Steenbreker, Jan Zoll, Tim J. H. Baltussen, Paul E. Verweij and Willem J. G. Melchers

J. Fungi 2023, 9(8), 807; https://doi.org/10.3390/jof9080807 - 30 Jul 2023

Cited by 1 | Viewed by 1474

Abstract

The opportunistic pathogen Aspergillus fumigatus is found on all continents and thrives in soil and agricultural environments. Its ability to readily adapt to novel environments and to produce billions of spores led to the spread of azole-resistant A. fumigatus across the globe, posing [...] Read more.

The opportunistic pathogen Aspergillus fumigatus is found on all continents and thrives in soil and agricultural environments. Its ability to readily adapt to novel environments and to produce billions of spores led to the spread of azole-resistant A. fumigatus across the globe, posing a threat to many immunocompromised patients, including critically ill patients with severe influenza or COVID-19. In our study, we sought to compare the adaptational response to azoles from A. fumigatus isolates that differ in azole susceptibility and genetic background. To gain more insight into how short-term adaptation to stressful azole compounds is managed through gene expression, we conducted an RNA-sequencing study on the response of A. fumigatus to itraconazole and the newest clinically approved azole, isavuconazole. We observed many similarities in ergosterol biosynthesis up-regulation across isolates, with the exception of the pan-azole-resistant isolate, which showed very little differential regulation in comparison to other isolates. Additionally, we found differential regulation of membrane efflux transporters, secondary metabolites, iron metabolism, and various stress response and cell signaling mechanisms. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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17 pages, 1904 KiB

Open AccessArticle

Synthesis of Altissimacoumarin D and Other Prenylated Coumarins and Their Ability to Reverse the Multidrug Resistance Phenotype in Candida albicans

by Anna Claudia Silva, Daniel Clemente de Moraes, Denilson Costa do Carmo, Giselle Cristina Casaes Gomes, A. Ganesan, Rosangela Sabbatini Capella Lopes, Antonio Ferreira-Pereira and Cláudio Cerqueira Lopes

J. Fungi 2023, 9(7), 758; https://doi.org/10.3390/jof9070758 - 18 Jul 2023

Cited by 1 | Viewed by 1135

Abstract

Azoles are the main antifungal agents employed in clinical practice to treat invasive candidiasis. Nonetheless, their efficacy is limited by fungal resistance mechanisms, mainly the overexpression of efflux pumps. Consequently, candidiasis has a worrisome death rate of 75%. One potential strategy to overcome [...] Read more.

Azoles are the main antifungal agents employed in clinical practice to treat invasive candidiasis. Nonetheless, their efficacy is limited by fungal resistance mechanisms, mainly the overexpression of efflux pumps. Consequently, candidiasis has a worrisome death rate of 75%. One potential strategy to overcome efflux-mediated resistance is to inhibit this process. Ailanthus altissima is a Chinese tree that produces several active substances, including altissimacoumarin D. Due to the low yield of its extraction and the need to search for new drugs to treat candidiasis, this study aimed to synthesize altissimacoumarin D and its analogues, as well as evaluating their ability to reverse the resistance phenotype of Candida albicans. Coumarin isofraxidin was prepared via total synthesis through a solvent-free Knoevenagel condensation as the key step. Isofraxidin and other commercially available coumarins were alkylated with prenyl or geranyl groups to yield the natural product altissimacoumarin D and seven analogues. The antifungal activity of the coumarins and their ability to reverse the fungal resistance phenotype were assessed using microbroth methodologies. Toxicity was evaluated using erythrocytes and an in silico prediction. All compounds improved the antifungal activity of fluconazole by inhibiting efflux pumps, and ACS47 and ACS50 were the most active. None of the coumarins were toxic to erythrocytes. In silico predictions indicate that ACS47 and ACS50 may be safe for human use. ACS47 and ACS50 are promising candidates when used as adjuvants in the antifungal therapy against C. albicans-resistant strains. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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9 pages, 1652 KiB

Open AccessArticle

Candida auris in Dog Ears

by Anamika Yadav, Yue Wang, Kusum Jain, Vijay Amrit Raj Panwar, Hardeep Kaur, Vikas Kasana, Jianping Xu and Anuradha Chowdhary

J. Fungi 2023, 9(7), 720; https://doi.org/10.3390/jof9070720 - 30 Jun 2023

Cited by 8 | Viewed by 8408

Abstract

Candida auris is an emerging global public health threat and is resistant to most antifungal agents. Though fungi are significant pathogens for animals, the role of C. auris in animal health remains unexplored. Here, we analysed the microbial cultures of skin and ear [...] Read more.

Candida auris is an emerging global public health threat and is resistant to most antifungal agents. Though fungi are significant pathogens for animals, the role of C. auris in animal health remains unexplored. Here, we analysed the microbial cultures of skin and ear swabs of 87 dogs in Delhi and performed fungal meta-barcode sequencing of ear and skin samples of 7 dogs with confirmed otitis externa (OE). Overall, 4.5% of dogs (4/87) with chronic skin infections contained evidence of C. auris in their ear canal (n = 3) and on their skin surface (n = 1). Of the three OE dogs with C. auris infection/colonisation, a diversity of fungi was observed, and their meta-barcode ITS sequence reads for C. auris ranged from 0.06% to 0.67%. Whole-genome sequencing of six C. auris strains obtained in culture from two dogs showed relatedness with Clade I clinical strains. The report highlights the isolation of C. auris from an animal source; however, the routes of transmission of this yeast to dogs and the clinical significance of transmission between dogs and humans remain to be investigated. Full article

(This article belongs to the Special Issue Multidrug-Resistant Fungi)

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