Assessment of the antifungal susceptibility of Malassezia pachydermatis in various media using a CLSI protocol

Cafarchia, Claudia; Figueredo, Luciana Aguiar; Favuzzi, Vincenza; Surico, Mariannna R.; Colao, Valeriana; Iatta, Roberta; Montagna, Maria Teresa; Otranto, Domenico

doi:10.1016/j.vetmic.2012.04.034

Cited by 56 publications

(65 citation statements)

References 17 publications

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“…Our isolate showed suboptimal growth on RPMI 1640 medium even with lipid supplementation, hence MIC readings were taken after 48 h [24]. Since our isolate did not grow on Mueller–Hinton medium (with or without oil supplementation), MICs were also determined on SDA for confirming results (Table 1).…”

Section: Discussionmentioning

confidence: 60%

Malassezia pachydermatis fungemia in a preterm neonate resistant to fluconazole and flucytosine

Al‐Sweih

Ahmad

Joseph

et al. 2014

Medical Mycology Case Reports

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A case of Malassezia pachydermatis fungemia in a preterm neonate is described. The isolate was identified by rDNA sequencing and was resistant to fluconazole and flucytosine. Since M. pachydermatis does not require lipid supplementation for growth, it can be misidentified as a Candida species. The report highlights M. pachydermatis as a cause of late onset sepsis in preterm neonates and emphasizes the need for prior antifungal susceptibility testing.

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Section: Discussionmentioning

confidence: 60%

Malassezia pachydermatis fungemia in a preterm neonate resistant to fluconazole and flucytosine

Al‐Sweih

Ahmad

Joseph

et al. 2014

Medical Mycology Case Reports

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“…Although the low azole susceptibility of M. pachydermatis and M. furfur is a well‐documented phenomenon, the mechanisms involved in azole drug defence are completely unknown, therefore the results of this study might serve by having more thorough investigations into these findings. Interestingly, the mechanisms involved in the defence against FLZ might be different from those against VOR as previously reported for Candida spp., since HAL reduces the MIC values of both azoles herein tested, whereas PTZ only those of VOR.…”

Section: Discussionmentioning

confidence: 99%

“…The antifungal susceptibility of M. pachydermatis and M. furfur strains was performed using a modified broth microdilution Clinical and Laboratory Standard Institute protocol (CLSI BMD M27‐A3) . In brief, Sabouraud dextrose broth (SDB, Liofilchem Diagnostici ® , Roseto degli Abruzzi, Italy) with 1% Tween 80 (Sigma Co, Milano, Italy) was used instead of RPMI 1640 medium as previously reported . Stock inoculum suspension was prepared from 4‐day‐old colonies on modified Dixon agar at 32°C in sterile distilled water and adjusted to an optical density of 2.4 McFarland using a turbidimeter (DEN‐1 McFarland Densitometer, Biosan, Riga, Latvia), equivalent to 1‐5 × 10 6 colony forming units (CFU)/mL, as inferred by quantitative plate counts of CFU in Dixon agar.…”

Section: Methodsmentioning

confidence: 99%

The role of drug efflux pumps in Malassezia pachydermatis and Malassezia furfur defence against azoles

Iatta

Puttilli

Immediato

et al. 2016

Mycoses

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This study aims to evaluate the effect of efflux pump modulators (EPMs) on the minimal inhibitory concentration (MIC) of fluconazole (FLZ) and voriconazole (VOR) in Malassezia furfur and Malassezia pachydermatis. The in vitro efficacy of azoles, in combination with EPMs (ie haloperidol-HAL, promethazine-PTZ and cyclosporine A-CYS), against 21 M. furfur from bloodstream infection patients and 14 M. pachydermatis from the skin of dogs with dermatitis, was assessed using a broth microdilution chequerboard analysis. Data were analysed using the model-fractional inhibitory concentration index (FICI) method. The MIC of FLZ and VOR of Malassezia spp. decreased in the presence of sub-inhibitory concentrations of HAL and/or PTZ. The synergic effect was observed only in strains with FLZ MIC≥128 μg/mL for M. furfur, FLZ MIC≥64 μg/mL for M. pachydermatis and VOR MIC≥4 μg/mL in both Malassezia spp. These results suggest that the drug efflux pumps are involved as defence mechanisms to azole drugs in Malassezia yeast. The synergism might be related to an increased expression of efflux pump genes, eventually resulting in azole resistance phenomena. Finally, the above FLZ and VOR MIC values might be considered the cut-off to discriminate susceptible and resistant strains.

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“…A variety of alternative procedures, most of which use lipid-enriched media, have been proposed, but published studies have mainly focused on M. pachydermatis susceptibility to ketoconazole, itraconazole, and other azole derivatives (e.g., [8][9][10][11][12][13][14][15][16][17]. On the contrary, information on the in vitro susceptibility of M. pachydermatis isolates to the polyene amphotericin B, which is commonly used for treating bloodstream infections in human patients (5-7), is scarcer; the available studies were based on a single method and/or a low number of isolates (see Table 1), so the reliability of their results cannot be adequately assessed.…”

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confidence: 99%

“…The BMD procedure was performed according to the CLSI guidelines for antifungal susceptibility testing of yeasts (18) but using SDB supplemented with 1% (vol/vol) Tween 80 (SDB-T 80 ) as the test medium instead of lipidfree RPMI 1640, as proposed by Cafarchia et al (9)(10)(11) and Eichenberg et al (12). Amphotericin B (Sigma-Aldrich, Madrid, Spain) stock solutions were prepared in 100% dimethyl sulfoxide (Sigma-Aldrich), further diluted in SDB-T 80 , and dispensed into 96-well microdilution trays.…”

mentioning

confidence: 99%

In Vitro Amphotericin B Susceptibility of Malassezia pachydermatis Determined by the CLSI Broth Microdilution Method and Etest Using Lipid-Enriched Media

Álvarez‐Pérez

Blanco

Peláez

et al. 2014

Antimicrob Agents Chemother

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We determined the in vitro amphotericin B susceptibility of 60 Malassezia pachydermatis isolates by the CLSI broth microdilution method and the Etest using lipid-enriched media. All isolates were susceptible at MICs of <1 g/ml, confirming the high activity of amphotericin B against this yeast species. Overall, the essential agreement between the tested methods was high (80% and 96.7% after 48 h and 72 h, respectively), and all discrepancies were regarded as nonsubstantial. Malassezia pachydermatis is a lipophilic but non-lipid-dependent basidiomycetous yeast which thrives on the skin of most warm-blooded vertebrates (1-3). Although generally regarded as a commensal microorganism, M. pachydermatis can become pathogenic under the influence of diverse factors, leading to different clinical forms of dermatitis and/or otitis, mainly in small animals (1, 2, 4). Systemic infections caused by this yeast species are only rarely encountered, but some outbreaks of fungemia have been reported in intensive care nurseries (5, 6). Notably, in one such outbreak, the introduction of the yeast into a nursery was linked to its possible zoonotic transmission from colonized pet dogs to the health care workers' hands, with further spread of the microorganism in the unit through person-to-person contact (5).Antifungal susceptibility testing of Malassezia species remains a challenge, as their growth is not supported (or, in the case of M. pachydermatis, only poorly supported) on the standard lipid-free RPMI growth medium recommended for yeast testing by the CLSI and EUCAST (6-8). A variety of alternative procedures, most of which use lipid-enriched media, have been proposed, but published studies have mainly focused on M. pachydermatis susceptibility to ketoconazole, itraconazole, and other azole derivatives (e.g., 8-17). On the contrary, information on the in vitro susceptibility of M. pachydermatis isolates to the polyene amphotericin B, which is commonly used for treating bloodstream infections in human patients (5-7), is scarcer; the available studies were based on a single method and/or a low number of isolates (see Table 1), so the reliability of their results cannot be adequately assessed.The aim of this study was to expand the database of MIC values to amphotericin B for M. pachydermatis isolates, as determined by two different procedures using lipid-enriched media, (i) a modified broth microdilution (BMD) method based on CLSI guidelines (18) and (ii) the Etest, which is a commercial agar-based gradient technique that is widely used for antifungal susceptibility testing of yeasts.Isolates. A total of 60 Malassezia pachydermatis isolates obtained from clinical cases of canine otitis and primarily recovered in Sabouraud dextrose agar (SDA) containing 0.005% chloramphenicol (bioMérieux, Marcy l'Etoile, France) were included in this study. They were identified as M. pachydermatis on the basis of their macroscopic and microscopic morphologies and their ability to grow on media without lipid supplementation, such as SDA, at 32°C (19)...

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Assessment of the antifungal susceptibility of Malassezia pachydermatis in various media using a CLSI protocol

Cited by 56 publications

References 17 publications

Malassezia pachydermatis fungemia in a preterm neonate resistant to fluconazole and flucytosine

Malassezia pachydermatis fungemia in a preterm neonate resistant to fluconazole and flucytosine

The role of drug efflux pumps in Malassezia pachydermatis and Malassezia furfur defence against azoles

In Vitro Amphotericin B Susceptibility of Malassezia pachydermatis Determined by the CLSI Broth Microdilution Method and Etest Using Lipid-Enriched Media

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