Sphingolipids mediate differential echinocandin susceptibility in Candida albicans and Aspergillus nidulans.

The cell wall synthesis-inhibiting echinocandins, including caspofungin and micafungin, play important roles in the treatment of candidiasis and aspergillosis. Previous studies revealed that, in the haploid yeast Candida glabrata, sphingolipid biosynthesis pathway mutations confer caspofungin reduced susceptibility (CRS) but micafungin increased susceptibility (MIS). Here, we describe one Candida albicans strain (of 10 tested) that similarly yields CRS-MIS mutants at relatively high frequency.

Flucytosine antagonism of azole activity versus Candida glabrata: role of transcription factor Pdr1 and multidrug transporter Cdr1.

Infections with the opportunistic yeast Candida glabrata have increased dramatically in recent years. Antifungal therapy of yeast infections commonly employs azoles, such as fluconazole (FLC), but C. glabrata frequently develops resistance to these inhibitors of ergosterol biosynthesis.

Vaginal toxic shock reaction triggering desquamative inflammatory vaginitis.

Objective: The study aimed to report 2 cases of desquamative inflammatory vaginitis associated with toxic shock syndrome toxin 1 (TSST-1)-producing Staphylococcus aureus strains.

Materials And Methods: Case report of 2 patients, 1 with an acute and 1 with a chronic presentation, diagnosed with desquamative inflammatory vaginitis on the basis of clinical findings and wet mount microscopy. Pretreatment and posttreatment vaginal bacterial and yeast cultures were obtained.

Fks1 and Fks2 are functionally redundant but differentially regulated in Candida glabrata: implications for echinocandin resistance.

The echinocandins caspofungin, micafungin, and anidulafungin, inhibitors of cell wall β-1,3-glucan synthesis, were recently elevated to first-line agents for treating infections due to the azole-refractory yeast Candida glabrata. In Candida albicans, echinocandin resistance is strictly associated with mutations in Fks1, a large integral membrane protein and putative β-1,3-glucan synthase, while mutations in both Fks1 and its paralog Fks2 (but not Fks3) have been associated with resistance in C. glabrata.

CRS-MIS in Candida glabrata: sphingolipids modulate echinocandin-Fks interaction.

Infections with the azole-refractory yeast Candida glabrata are now commonly treated with the echinocandins caspofungin (CSF) or micafungin (MCF). True resistance (>  32-fold decreased susceptibility) to these lipopeptide inhibitors of cell wall synthesis is rare and strictly associated with mutations in integral membrane proteins Fks1 or Fks2. In contrast, mutants exhibiting 4- to 32-fold CSF reduced susceptibility (CRS) were readily selected in vitro, and surprisingly demonstrated 4- to 32-fold MCF increased susceptibility (MIS).

Topological and mutational analysis of Saccharomyces cerevisiae Fks1.

Fks1, with orthologs in nearly all fungi as well as plants and many protists, plays a central role in fungal cell wall formation as the putative catalytic component of β-1,3-glucan synthase. It is also the target for an important new antifungal group, the echinocandins, as evidenced by the localization of resistance-conferring mutations to Fks1 hot spots 1, 2, and 3 (residues 635 to 649, 1354 to 1361, and 690 to 700, respectively). Since Fks1 is an integral membrane protein and echinocandins are cyclic peptides with lipid tails, Fks1 topology is key to understanding its function and interaction with echinocandins.

Candida glabrata mutants demonstrating paradoxical reduced caspofungin susceptibility but increased micafungin susceptibility.

Echinocandins, including caspofungin (CSP) and micafungin (MCF), are highly active versus Candida glabrata (MIC of ≤0.06 μg/ml). True resistance (MIC of ≥1 μg/ml) is a rare event and strictly associated with mutations in β-1,3-glucan synthase gene FKS1 or FKS2.

New Fks hot spot for acquired echinocandin resistance in Saccharomyces cerevisiae and its contribution to intrinsic resistance of Scedosporium species.

Echinocandins represent a new antifungal group with potent activity against Candida species. These lipopeptides inhibit the synthesis of β-1,3-glucan, the major cell wall polysaccharide. Acquired resistance or reduced echinocandin susceptibility (RES) is rare and associated with mutations in two "hot spot" regions of Fks1 or Fks2, the probable β-1,3-glucan synthases.

Mutational analysis of flucytosine resistance in Candida glabrata.

The antifungal flucytosine (5-fluorocytosine [5FC]) is a prodrug metabolized to its toxic form, 5-fluorouracil (5FU), only by organisms expressing cytosine deaminase. One such organism is Candida glabrata, which has emerged as the second most common agent of bloodstream and mucosal candidiasis. This emergence has been attributed to the high rate at which C.

Role for Fks1 in the intrinsic echinocandin resistance of Fusarium solani as evidenced by hybrid expression in Saccharomyces cerevisiae.

The opportunistic mold Fusarium solani is intrinsically resistant to cell wall synthesis-inhibiting echinocandins (ECs), including caspofungin and micafungin. Mutations that confer acquired EC resistance in Saccharomyces cerevisiae and other normally susceptible yeast species have been mapped to the Fks1 gene; among these is the mutation of residue 639 from Phe to Tyr (F639Y) within a region designated hot spot 1. Fks1 sequence analysis identified the equivalent of Y639 in F.

A naturally occurring proline-to-alanine amino acid change in Fks1p in Candida parapsilosis, Candida orthopsilosis, and Candida metapsilosis accounts for reduced echinocandin susceptibility.

Candida parapsilosis has emerged as a common cause of invasive fungal infection, especially in Latin America and in the neonatal setting. C. parapsilosis is part of a closely related group of organisms that includes the species Candida orthopsilosis and Candida metapsilosis.

Increases in SLT2 expression and chitin content are associated with incomplete killing of Candida glabrata by caspofungin.

Incomplete killing was observed for caspofungin against Candida glabrata, which was associated with increased SLT2 expression and elevated chitin content. In contrast, fungicidal activity and no chitin increase were observed in an isogenic Delta slt2 strain, suggesting a role for SLT2 and chitin production in the response of C. glabrata to caspofungin.

Candida albicans and Candida glabrata clinical isolates exhibiting reduced echinocandin susceptibility.

A recognized hotspot for mutations conferring reduced echinocandin susceptibility (RES) is residue S645 of Candida albicans Gsc1(Fks1). We report that the mutation F641Y is associated with RES in a C. albicans isolate.

Pdr1 regulates multidrug resistance in Candida glabrata: gene disruption and genome-wide expression studies.

Candida glabrata emerged in the last decade as a common cause of mucosal and invasive fungal infection, in large part due to its intrinsic or acquired resistance to azole antifungals such as fluconazole. In C. glabrata clinical isolates, the predominant mechanism behind azole resistance is upregulated expression of multidrug transporter genes CDR1 and PDH1.

Proteomic analysis of experimentally induced azole resistance in Candida glabrata.

Objectives: The aim of the present study was to identify changes in the proteome of a laboratory-derived azole-resistant strain of Candida glabrata compared with its susceptible parent strain in an effort to identify proteins that are differentially expressed in association with azole resistance.

Methods: Soluble and membrane protein fractions were isolated from mutant strain F15 (fluconazole MIC>128 mg/L) and parent strain 66032 (fluconazole MIC=16 mg/L) grown to mid-log phase. Soluble proteins were resolved by both two-dimensional (2D) and one-dimensional (1D) polyacrylamide gel electrophoresis (GE) whereas membrane proteins were resolved by 1D GE.

Promoter-dependent disruption of genes: simple, rapid, and specific PCR-based method with application to three different yeast.

PCR product-based gene disruption has greatly accelerated molecular analysis of Saccharomyces cerevisiae. This approach involves amplification of a marker gene (e.g.

Effects of cetylpyridinium chloride resistance and treatment on fluconazole activity versus Candida albicans.

Mouthwash antiseptic cetylpyridinium chloride (CPC) has potent activity against Candida albicans; however, two of five azole-resistant strains showed reduced CPC susceptibility. To further examine the potential for cross-resistance, CPC-resistant mutants were selected in vitro and their fluconazole susceptibility was tested. MICs were unchanged, and trailing growth generally decreased.

Azole resistance in Candida glabrata: coordinate upregulation of multidrug transporters and evidence for a Pdr1-like transcription factor.

Candida glabrata has emerged as a common cause of fungal infection. This yeast has intrinsically low susceptibility to azole antifungals such as fluconazole, and mutation to frank azole resistance during treatment has been documented. Potential resistance mechanisms include changes in expression or sequence of ERG11 encoding the azole target.

Cyclic AMP signaling pathway modulates susceptibility of candida species and Saccharomyces cerevisiae to antifungal azoles and other sterol biosynthesis inhibitors.

Azoles are widely used antifungals; however, their efficacy is compromised by fungistatic activity and selection of resistant strains during treatment. Recent studies demonstrated roles for the protein kinase C and calcium signaling pathways in modulating azole activity. Here we explored a role for the signaling pathway mediated by cyclic AMP (cAMP), which is synthesized by the regulated action of adenylate cyclase (encoded by CDC35 in Candida albicans and CYR1 in Saccharomyces cerevisiae) and cyclase-associated protein (encoded by CAP1 and SRV2, respectively).

ROX1 and ERG regulation in Saccharomyces cerevisiae: implications for antifungal susceptibility.

Yeasts respond to treatment with azoles and other sterol biosynthesis inhibitors by upregulating the expression of the ERG genes responsible for ergosterol production. Previous studies on Saccharomyces cerevisiae implicated the ROX1 repressor in ERG regulation. We report that ROX1 deletion resulted in 2.

Histone deacetylase inhibitors enhance Candida albicans sensitivity to azoles and related antifungals: correlation with reduction in CDR and ERG upregulation.

Histone acetylation and deacetylation play important roles in eukaryotic gene regulation. Several histone deacetylase (HDA) inhibitors have been characterized, including trichostatin A (TSA), apicidin, and sodium butyrate. We tested their effects on Candida albicans in vitro growth, heat sensitivity, and germ tube formation; minimal effects were observed.

Antifungal activity in Saccharomyces cerevisiae is modulated by calcium signalling.

The most important group of antifungals is the azoles (e.g. miconazole), which act by inhibiting lanosterol demethylase in the sterol biosynthesis pathway.

Cloning of the haemocin locus of Haemophilus influenzae type b and assessment of the role of haemocin in virulence.

The bacteriocin haemocin (HMC) is produced by most type b strains of Haemophilus influenzae, including strains determined to be genetically diverse, and is toxic to virtually all non-type b strains of H. influenzae, both encapsulated and non-encapsulated. Examination of the deduced amino acid sequences of several genes upstream of the previously identified HMC immunity gene (hmcI) revealed several features common to class II bacteriocins of certain Gram-positive bacteria.

beta-Tubulin genes and the basis for benzimidazole sensitivity of the opportunistic fungus Cryptococcus neoformans.

The basidiomycete Cryptococcus neoformans causes life-threatening infections in immunocompromised patients, and available chemotherapeutic agents are potentially toxic or have limited efficacy. In vitro, C. neoformans is very sensitive to selected benzimidazole compounds (e.