The current global scenario presents us with a growing increase in infections caused by fungi, referred to by specialists in the field as a "silent epidemic", aggravated by the limited pharmacological arsenal and increasing resistance to this therapy. For this reason, drug repositioning and therapeutic compound combinations are promising strategies to mitigate this serious problem. In this context, this study investigates the antifungal activity of the non-toxic, low-cost and widely available cationic polyelectrolyte Poly(diallyldimethylammonium chloride) (PDDA), in combination with different antifungal drugs: systemic (amphotericin B, AMB), topical (clioquinol, CLIO) and oral (nitroxoline, NTX). For each combination, different drug:PDDA ratios were tested and, through the broth microdilution technique, the minimum inhibitory concentration (MIC) of these drugs in the different ratios against clinically important Candida species strains was determined. Overall, PDDA combinations with the studied drugs demonstrated a significant increase in drug activity against most strains, reaching MIC reductions of up to 512 fold for the fluconazole resistant Candida krusei (Pichia kudriavzevii). In particular, the AMB-PDDA combination 1:99 was highly effective against AMB-resistant strains, demonstrating the excellent profile of PDDA as an adjuvant/association in novel antifungal formulations with outdated conventional drugs.
- MeSH
- amfotericin B farmakologie MeSH
- antifungální látky * farmakologie MeSH
- Candida * účinky léků MeSH
- fungální léková rezistence MeSH
- kandidóza mikrobiologie farmakoterapie MeSH
- kvartérní amoniové sloučeniny * farmakologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti * MeSH
- Pichia MeSH
- polyelektrolyty farmakologie MeSH
- polyethyleny farmakologie chemie MeSH
- synergismus léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The rising number of invasive fungal infections caused by drug-resistant Candida strains is one of the greatest challenges for the development of novel antifungal strategies. The scarcity of available antifungals has drawn attention to the potential of natural products as antifungals and in combinational therapies. One of these is catechins-polyphenolic compounds-flavanols, found in a variety of plants. In this work, we evaluated the changes in the susceptibility of Candida glabrata strain characterized at the laboratory level and clinical isolates using the combination of catechin and antifungal azoles. Catechin alone had no antifungal activity within the concentration range tested. Its use in combination with miconazole resulted in complete inhibition of growth in the sensitive C. glabrata isolate and a significant growth reduction in the azole resistant C. glabrata clinical isolate. Simultaneous use of catechin and miconazole leads to increased intracellular ROS generation. The enhanced susceptibility of C. glabrata clinical isolates to miconazole by catechin was accompanied with the intracellular accumulation of ROS and changes in the plasma membrane permeability, as measured using fluorescence anisotropy, affecting the function of plasma membrane proteins.
This study was designed to evaluate the prevalence of antifungal resistance, genetic mechanisms associated with in vitro induction of azole and echinocandin resistance and genotyping of Candida krusei, which is intrinsically resistant to fluconazole and is recovered from clinical and nonclinical sources from different countries. Our results indicated that all the isolates were susceptible or had the wild phenotype (WT) to azoles, amphotericin B, and only 1.27% showed non-WT for flucytosine. Although 70.88% of the isolates were resistant to caspofungin, none of them were categorized as echinocandin-resistant as all were susceptible to micafungin and no FKS1 hot spot 1 (HS1) or HS2 mutations were detected. In vitro induction of azole and echinocandin resistance confirmed the rapid development of resistance at low concentrations of fluconazole (4 μg/ml), voriconazole (0.06 μg/ml), and micafungin (0.03 μg/ml), with no difference between clinical and nonclinical isolates in the resistance development. Overexpression of ABC1 gene and FKS1 HS1 mutations were the major mechanisms responsible for azole and echinocandin resistance, respectively. Genotyping of our 79 isolates coupled with 217 other isolates from different sources and geography confirmed that the isolates belong to two main subpopulations, with isolates from human clinical material and Asia being more predominant in cluster 1, and environmental and animals isolates and those from Europe in cluster 2. Our results are of critical concern, since realizing that the C. krusei resistance mechanisms and their genotyping are crucial for guiding specific therapy and for exploring the potential infection source.
- MeSH
- antifungální látky farmakologie terapeutické užití MeSH
- azoly * farmakologie MeSH
- echinokandiny * farmakologie MeSH
- fungální léková rezistence genetika MeSH
- genotyp MeSH
- mikrobiální testy citlivosti MeSH
- Pichia MeSH
- prevalence MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Závažný medicínsky problém v súčasnosti predstavujú mykotické infekcie. Život ohrozujúce stavy, ktoré sú asociované najmä s imunokompromitovanými pacientami, spôsobujú vo veľkej miere zástupcovia z rodu Candida. Najčastejším pôvodcom je kvasinka Candida albicans, v posledných rokoch však dochádza k výraznému posunu k druhu Candida glabrata a ďalším tzv. non-albicans Candida kvasinkám (napr. Candida tropicalis, Candida parapsilosis). S vysokou mortalitou sú asociované invazívne infekcie spôsobované multirezistentnou kvasinkou Candida auris. Medzi kvasinkou C. glabrata a ostatnými pôvodcami kandidóz existuje niekoľko rozdielov v biologických vlastnostiach, ako aj vo faktoroch prispievajúcich k virulencii. Vrodene zvýšená rezistencia voči azolom je, spolu so schopnosťou rýchlo nadobúdať rezistenciu aj voči ostatným skupinám antifungálnych látok, nebezpečnou kombináciou pri zvládaní úspešnej liečby kandidových infekcií. Poznanie faktorov podieľajúcich sa na virulencii a mechanizmov vedúcich k rezistencii patogéna voči antifungálnym látkam môže viesť k lepšiemu zvládaniu kandidových infekcií. Nemenej dôležitým je hľadanie nových cieľových miest pre antifungálnu terapiu. Predložená práca stručne sumarizuje existujúce poznatky, ktoré sa venujú uvedenej problematike.
Fungal infections are currently a serious health concern. Life-threatening conditions that occur mainly in immunocompromised patients are largely caused by representatives of the genus Candida. The most common causative agent is the yeast Candida albicans, but in recent years there has been a significant shift towards Candida glabrata and other so-called non-albicans Candida yeasts (e.g. Candida tropicalis or Candida parapsilosis). Invasive infections caused by the multidrug-resistant yeast Candida auris are associated with high mortality. There are several differences between C. glabrata and other causative agents of candidiasis in biological characteristics and virulence factors. The innate increased resistance to azoles along with the ability to rapidly acquire resistance to other groups of antifungal agents is a dangerous combination which makes it difficult to manage Candida infections. A better understanding of the virulence factors and mechanisms of resistance to antifungal agents can benefit the management of Candida infections. Equally important is the search for new target sites for antifungal therapy. The present work briefly summarizes the existing knowledge in this area.
- MeSH
- antifungální látky farmakologie terapeutické užití MeSH
- biofilmy MeSH
- Candida glabrata * MeSH
- Candida MeSH
- faktory virulence MeSH
- fungální léková rezistence * MeSH
- kandidóza * farmakoterapie mikrobiologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- virulence MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Systemic fungal diseases and antifungal resistance represent a serious problem in human medicine and con-tribute to increased patient mortality. The most common causes of these diseases are opportunistic yeasts of the genus Candida. C. albicansis considered to be the main pathogen, together with C. glabrata, C. tropicalis, C. par-apsilosis, and C.krusei. Azole antifungals predominate in the treatment of the systemic mycoses. For antifungal re-sistance in Candidaspp. some genes and their mutations are responsible, the genes ERG11, CDR1, CDR2and MDR1being considered the most important. The main target of azole antifungals is the process of ergosterol syn-thesis. Due to ergosterol crucial functions and its unique structural properties, the synthesis of ergosterol and its individual steps represent the target of most clinically available antifungals. The biofilm appears to be a signifi-cant virulence factor of the yeast Candidaspp. It allows hematogenous dissemination of cells, prevents the effect of antifungals on all cells during treatment and leads to a high level of antimicrobial resistance. The antifungal re-sistance in candidiasis often has a multifactorial origin, which must be considered in the treatment of systemic mycoses and in the development of new antifungals.
- MeSH
- antifungální látky chemie farmakologie terapeutické užití MeSH
- azoly farmakologie terapeutické užití MeSH
- biofilmy účinky léků MeSH
- Candida patogenita účinky léků MeSH
- ergosterol biosyntéza MeSH
- faktory virulence MeSH
- flukonazol farmakologie terapeutické užití MeSH
- fungální léková rezistence MeSH
- itrakonazol farmakologie terapeutické užití MeSH
- kandidóza * farmakoterapie mikrobiologie MeSH
- lidé MeSH
- vorikonazol farmakologie terapeutické užití MeSH
- Check Tag
- lidé MeSH
BACKGROUND: Antifungal drug resistance in dermatophytes was first reported shortly after the turn of the millennium and has today been reported in Trichophyton and occasionally in Microsporum, but not in Epidermophyton species. Although drug resistance in dermatophytes is not routinely investigated, resistance in Trichophyton spp. is increasingly reported worldwide. The highest rates are observed in India (36% and 68% for terbinafine (MIC ≥4 mg/L) and fluconazole (MICs ≥16 mg/L), respectively), and apparently involve the spread of a unique clade related to the Trichophyton mentagrophytes/Trichophyton interdigitale complex. OBJECTIVES: The European Committee on Antimicrobial Susceptibility Testing Subcommittee on Antifungal Susceptibility Testing (EUCAST-AFST) has released a new method (E.Def 11.0) for antifungal susceptibility testing against microconidia-forming dermatophytes including tentative MIC ranges for quality control strains and tentative breakpoints against Trichophyton rubrum and T. interdigitale. Here, the details of the new procedure E.Def 11.0 are described. SOURCES: This technical note is based on the multicentre validation of the EUCAST dermatophyte antifungal susceptibility testing method, the mould testing method (E.Def 9.3.2) and the updated quality control tables for antifungal susceptibility testing document, v 5.0 (available on the EUCAST website). CONTENTS: The method is based on the EUCAST microdilution method for moulds but significant differences include: (a) an altered test medium selective for dermatophytes; (b) an altered incubation time and temperature; and (c) a different end-point criterion (spectrophotometric determination) of fungal growth. It can easily be implemented in laboratories already performing EUCAST microdilution methods and has been validated for terbinafine, voriconazole, itraconazole and amorolfine against T. rubrum and T. interdigitale. IMPLICATIONS: This standardized procedure with automated end-point reading will allow broader implementation of susceptibility testing of dermatophytes and so facilitate earlier appropriate therapy. This is important, as resistance is rapidly emerging and largely underdiagnosed.
Candida albicans is an opportunistic pathogen accounting for the majority of cases of Candida infections. Currently, C. albicans are developing resistance towards different classes of antifungal drugs and this has become a global health burden that does not spare Lebanon. This study aims at determining point mutations in genes known to be involved in resistance acquisition and correlating resistance to virulence and ergosterol content in the azole resistant C. albicans isolate CA77 from Lebanon. This pilot study is the first of its kind to be implemented in Lebanon. We carried out whole genome sequencing of the azole resistant C. albicans isolate CA77 and examined 18 genes involved in antifungal resistance. To correlate genotype to phenotype, we evaluated the virulence potential of this isolate by injecting it into BALB/c mice and we quantified membrane ergosterol. Whole genome sequencing revealed that eight out of 18 genes involved in antifungal resistance were mutated in previously reported and novel residues. These genotypic changes were associated with an increase in ergosterol content but no discrepancy in virulence potential was observed between our isolate and the susceptible C. albicans control strain SC5314. This suggests that antifungal resistance and virulence potential in this antifungal resistant isolate are not correlated and that resistance is a result of an increase in membrane ergosterol content and the occurrence of point mutations in genes involved in the ergosterol biosynthesis pathway.
- MeSH
- azoly farmakologie MeSH
- bodová mutace MeSH
- Candida albicans chemie účinky léků genetika patogenita MeSH
- ergosterol analýza MeSH
- fenotyp MeSH
- fungální léková rezistence genetika MeSH
- genotyp MeSH
- lidé MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- pilotní projekty MeSH
- sekvenování celého genomu * MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Libanon MeSH
Fungal infections cause >1 million deaths annually and the emergence of antifungal resistance has prompted the exploration for novel antifungal targets. Quadruplexes are four-stranded nucleic acid secondary structures, which can regulate processes such as transcription, translation, replication and recombination. They are also found in genes linked to virulence in microbes, and ligands that bind to quadruplexes can eliminate drug-resistant pathogens. Using a computational approach, we quantified putative quadruplex-forming sequences (PQS) in 1359 genomes across the fungal kingdom and explored their presence in genes related to virulence, drug resistance and biological processes associated with pathogenicity in Aspergillus fumigatus. Here we present the largest analysis of PQS in fungi and identify significant heterogeneity of these sequences throughout phyla, genera and species. PQS were genetically conserved in Aspergillus spp. and frequently pathogenic species appeared to contain fewer PQS than their lesser/non-pathogenic counterparts. GO-term analysis identified that PQS-containing genes were involved in processes linked with virulence such as zinc ion binding, the biosynthesis of secondary metabolites and regulation of transcription in A. fumigatus. Although the genome frequency of PQS was lower in A. fumigatus, PQS could be found enriched in genes involved in virulence, and genes upregulated during germination and hypoxia. Moreover, PQS were found in genes involved in drug resistance. Quadruplexes could have important roles within fungal biology and virulence, but their roles require further elucidation.
- MeSH
- algoritmy MeSH
- antifungální látky farmakologie MeSH
- Ascomycota MeSH
- Aspergillus fumigatus genetika MeSH
- Aspergillus MeSH
- fungální léková rezistence účinky léků MeSH
- genom fungální účinky léků MeSH
- genom virový MeSH
- transkriptom MeSH
- virulence MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
We evaluated the antifungal activity of benzylidene-carbonyl compounds (LINS03) based on the structure of gibbilimbol from Piper malacophyllum Linn. Five analogues (1-5) were synthetized following a classic aldol condensation between an aromatic aldehyde and a ketone, under basic conditions. These were tested against itraconazole-susceptible (n = 3) and itraconazole-resistant (n = 5) isolates of Sporothrix brasiliensis by M38-A2 guidelines of CLSI. All of them were fungistatic (MIC ranged of 0.11-0.22 mg/mL (1); 0.08-0.17 mg/mL (2); 0.05-0.1 mg/mL (3); 0.04-0.33 mg/mL (4); and 0.04-0.3 mg/mL (5)), highlighting compounds 2 and 3. As fungicidal, compounds 1 and 2 were highlighted (MFC ranged of 0.22-0.89 mg/mL and 0.08-1.35 mg/mL, respectively), compared with the remaining (0.77-> 3.08 mg/mL (3); 0.08-> 2.6 mg/mL (4); and 0.59-> 2.37 mg/mL (5)). The inhibitory activity was related to the benzylidene-carbonyl, whereas the phenol group and the low chain homolog seems to contribute to some extent to the fungicidal effect. Compound 2 highlighted due to the considerable fungistatic and fungicidal activities, including itraconazole-resistant Sporothrix brasiliensis. These findings support the potential usefulness of benzylidene-carbonyl compounds as promising prototypes for the development of antifungal against sporotrichosis by Sporothrix brasiliensis, including against itraconazole-resistant isolates.
- MeSH
- antifungální látky farmakologie MeSH
- benzylidenové deriváty farmakologie MeSH
- fungální léková rezistence účinky léků MeSH
- itrakonazol farmakologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiální viabilita účinky léků MeSH
- Sporothrix účinky léků izolace a purifikace MeSH
- sporotrichóza farmakoterapie mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Cryptococcosis is a potentially fatal fungal disease which has aggrandized with the emergence of AIDS and antifungal resistance. The currently used antifungals lack the broad-spectrum activity and result in several toxicities during long treatment regimens. Thus, the present study aims to evaluate the antifungal activity of cinnamaldehyde against Cryptococcus neoformans var. grubii, the etiological agent of the disease. Quantitative and qualitative in vitro fungal susceptibilities were carried out by minimum inhibitory concentration assay, flow cytometric analysis, and confocal microscopy. Micromorphological alterations were studied through scanning electron and light microscopies. "In vivo" antifungal efficacy of cinnamaldehyde was assessed. Cinnamaldehyde showed antifungal activity against C. neoformans in a dose-dependent manner. A concentration of 1.37 mg/mL of cinnamaldehyde was found to be inhibitory and fungicidal while the low concentration (0.68 mg/mL) was found to induce micromorphological changes and formation of giant/titan-like cells in this pathogen. The reparative activity of cinnamaldehyde and its ability to prolong the life even after the advent of cryptococcal meningitis in mice was also noticed. This study suggests potent anti-cryptococcal activity of cinnamaldehyde. Though, it has a couple of limitations like allergy and low bioavailability. However, these problems can be circumvented by developing suitable analogs of the compound. It, therefore, could be used as a therapeutic option against cryptococcosis and cryptococcal meningitis. Moreover, the evaluation of its pharmacokinetic and pharmacodynamic properties is desirable.
- MeSH
- akrolein analogy a deriváty farmakologie MeSH
- analýza přežití MeSH
- antifungální látky farmakologie MeSH
- Cryptococcus neoformans účinky léků MeSH
- fungální léková rezistence účinky léků MeSH
- játra patologie MeSH
- kryptokokóza farmakoterapie mikrobiologie patologie MeSH
- mikrobiální testy citlivosti MeSH
- modely nemocí na zvířatech MeSH
- mozek patologie MeSH
- mykózy farmakoterapie MeSH
- myši MeSH
- plíce patologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
