In vitro effects of micafungin against Candida biofilms on polystyrene and central venous catheter sections

Seidler, Marc; Salvenmoser, Stefanie; Müller, F.

doi:10.1016/j.ijantimicag.2006.07.024

Cited by 55 publications

(32 citation statements)

References 32 publications

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“…Seidler et al (31) have shown that profiles of high MICs could depend on the ability of Candida species to form biofilms on different substrates. In particular, the study demonstrated that MFG displays diminished activity (Ͼ16 mg/liter) against C. parapsilosis mature biofilms grown on polystyrene substrate but increased activity (Ͻ0.5 mg/liter) against biofilms grown on central venous catheter sections (31). Finally, interstudy differences could be due to either differences in the biofilm models used or the distinct clumping and irregular appearance of C. parapsilosis blastospores embedded within a shallow biofilm matrix that results in an easily dissociated biofilm structure (51,52).…”

Section: Discussionmentioning

confidence: 93%

“…Plates were then centrifuged at 4,000 rpm for 20 min and washed once with PBS to remove unattached cells, and 100 l of fresh RPMI 1640 was subsequently added. Mature biofilm production was documented by staining the polysaccharide structure of the extracellular matrix of biofilms with 0.1% safranin for 5 min and measuring the optical absorbance at 492 nm with a microplate reader (ChroMate 4300; Awareness Technology, Inc., Palm City, FL) (31). The documented biofilmproducing strain C. albicans M61, obtained from an infected intravascular catheter and previously extensively studied (32), was used as a control of biofilm formation.…”

Section: Methodsmentioning

confidence: 99%

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Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

Simitsopoulou

Peshkova

Tasina

et al. 2013

Antimicrob Agents Chemother

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e Candida species other than Candida albicans are increasingly recognized as causes of biofilm-associated infections. This is a comprehensive study that compared the in vitro activities of all three echinocandins against biofilms formed by different common and infrequently identified Candida isolates. We determined the activities of anidulafungin (ANID), caspofungin (CAS), and micafungin (MFG) against planktonic cells and biofilms of bloodstream isolates of C. albicans (15 strains), Candida parapsilosis (6 strains), Candida lusitaniae (16 strains), Candida guilliermondii (5 strains), and Candida krusei (12 strains) by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. Planktonic and biofilm MICs were defined as >50% fungal damage. Planktonic cells of all Candida species were susceptible to the three echinocandins, with MICs of <1 mg/liter. By comparison, differences in the MIC profiles of biofilms in response to echinocandins existed among the Candida species. Thus, C. lusitaniae and C. guilliermondii biofilms were highly recalcitrant to all echinocandins, with MICs of >32 mg/ liter. In contrast, the MICs of all three echinocandins for C. albicans and C. krusei biofilms were relatively low (MICs < 1 mg/ liter). While echinocandins exhibited generally high MICs against C. parapsilosis biofilms, MFG exhibited the lowest MICs against these isolates (4 mg/liter). A paradoxical growth effect was observed with CAS concentrations ranging from 8 to 64 mg/ liter against C. albicans and C. parapsilosis biofilms but not against C. krusei, C. lusitaniae, or C. guilliermondii. While nonalbicans Candida planktonic cells were susceptible to all echinocandins, there were drug-and species-specific differences in susceptibility among biofilms of the various Candida species, with C. lusitaniae and C. guilliermondii exhibiting profiles of high MICs of the three echinocandins.

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Section: Discussionmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

Simitsopoulou

Peshkova

Tasina

et al. 2013

Antimicrob Agents Chemother

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“…Biofilms grown for 48 h on an elastomer surface were developed according to methods previously described (13,55). To quantitate safranin O staining (11,45), 48-h biofilms grown on elastomer squares were stained with 1% safranin O solution. After 20 min of incubation at 25°C, the wells were washed with distilled water.…”

Section: Methodsmentioning

confidence: 99%

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

et al. 2011

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Like MTL-heterozygous (a/␣) cells, white MTL-homozygous (a/a or ␣/␣) cells of Candida albicans, to which a minority of opaque cells of opposite mating type have been added, form thick, robust biofilms. The latter biofilms are uniquely stimulated by the pheromone released by opaque cells and are regulated by the mitogenactivated protein kinase signal transduction pathway. However, white MTL-homozygous cells, to which opaque cells of opposite mating type have not been added, form thinner biofilms. Mutant analyses reveal that these latter biofilms are self-induced. Self-induction of a/a biofilms requires expression of the ␣-receptor gene STE2 and the ␣-pheromone gene MF␣, and self-induction of ␣/␣ biofilms requires expression of the a-receptor gene STE3 and the a-pheromone gene MFa. In both cases, deletion of WOR1, the master switch gene, blocks cells in the white phenotype and biofilm formation, indicating that self-induction depends upon low frequency switching from the white to opaque phenotype. These results suggest a self-induction scenario in which minority opaque a/a cells formed by switching secrete, in a mating-type-nonspecific fashion, ␣-pheromone, which stimulates biofilm formation through activation of the ␣-pheromone receptor of majority white a/a cells. A similar scenario is suggested for a white ␣/␣ cell population, in which minority opaque ␣/␣ cells secrete a-pheromone. This represents a paracrine system in which one cell type (opaque) signals a second highly related cell type (white) to undergo a complex response, in this case the formation of a unisexual white cell biofilm.Approximately 90% of Candida albicans isolates are a/␣ and 10% either a/a or ␣/␣ (24, 25, 50). For a/␣ strains to mate, they must undergo homozygosis to a/a or ␣/␣ (20, 21, 29). Then, a/a and ␣/␣ strains must switch from the white to opaque phenotype (46) in order to be mating competent (27,30). Opaque cells secrete a cell type-specific pheromone, which stimulates the mating response in cells of opposite mating type (5,26,38). However, in a fashion unique to C. albicans, these pheromones also induce mating-incompetent white cells, but not matingcompetent opaque cells, of opposite mating type to form robust biofilms, similar morphologically to those formed by a/␣ cells (13, 42-44, 48, 53-55). These MTL-homozygous white cell biofilms have been demonstrated in vitro to facilitate mating between opaque a/a and ␣/␣ cells (13,48).Although the addition of minority opaque cells of opposite mating type (1 to 10%) to a population of white cells increases the thickness of the final white cell biofilm by more than 50%, single-sex white a/a or ␣/␣ cell populations, to which cells of opposite mating types have not been added, also form robust biofilms composed of a basal layer of yeast cells and a thick upper layer of hyphae and matrix (13,(42)(43)(44)(53)(54)(55). We previously showed that deletion of the ␣-receptor gene STE2 results in highly reduced, abnormal white a/a cell biofilms in the absence of minority opaque ␣/␣ cells, suggesting t...

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“…Adherence to catheter material was measured by the method of Seidler et al (47). Arrow-Howes Hands-Off multilumen central venous catheters (radiopaque polyurethane) were a kind gift from Nigel Webster, University of Aberdeen.…”

Section: Vol 8 2009mentioning

confidence: 99%

Property Differences among the Four Major Candida albicans Strain Clades

et al. 2009

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A selection of 43 Candida albicans isolates, chosen to represent the four major strain clades of the species and also intraclade diversity, was screened for their virulence in the murine intravenous challenge model of C. albicans infection, for a range of properties measurable in vitro that might relate to virulence, and for the numbers of midrepeat sequences in genes of the ALS and HYR families. Heterozygosity at the mating type locus and low whole-cell acid phosphatase activity and growth rate at 40°C were found to be significantly positively associated with the most virulent isolates. Acid phosphatase activity and growth in 2 M NaCl were statistically significant variables between clades by univariate analysis. Isolates in different clades also differed significantly in midrepeat sequence alleles of ALS2, ALS4, ALS6, ALS7, ALS9, HYR1, and HYR2. There was no association between the midrepeat alleles of any ALS or HYR gene and the virulence of isolates to mice. Genome-wide transcript profiles of 20 isolates (5 per clade) grown under two conditions showed considerable variation between individual isolates, but only a small number of genes showed statistically significant differential gene expression between clades. Analysis of the expression profiles by overall strain virulence revealed 18 open reading frames differing significantly between isolates of high, intermediate, and low virulence. Four of these genes encoded functions related to phosphate uptake and metabolism. This finding and the significant association between whole-cell acid phosphatase activity and virulence led us to disrupt PHO100, which encodes a predicted periplasmic acid phosphatase. The pho100⌬ mutant was mildly but significantly attenuated in terms of survival curves in the mouse model. The study has extended the range of properties known to differ between C. albicans clades and suggests a possible but minor role of phosphate metabolism in the virulence of the species.

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In vitro effects of micafungin against Candida biofilms on polystyrene and central venous catheter sections

Cited by 55 publications

References 32 publications

Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

Property Differences among the Four Major Candida albicans Strain Clades

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