In vitro susceptibility of fluconazole-susceptible and -resistant isolates of Malassezia pachydermatis against azoles

Jesus, Francielli Pantella Kunz de; Lautert, Claudia; Zanette, Régis A.; Mahl, Deise Luiza; Azevedo, María Isabel de; Machado, Mauro L.S.; Dutra, Valéria; Botton, Sônia de Ávila; Alves, Sydney Hartz; Santúrio, Jânio Morais

doi:10.1016/j.vetmic.2011.04.027

Cited by 56 publications

(47 citation statements)

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“…The MICs and MFCs of ketoconazole and itraconazole were very low as expected from previous studies (Jesus et al, 2011;Cafarchia et al, 2012), and no resistant strain was found to either of the azoles according to the CLSI breakpoints, similarly as reported in earlier studies (Brito et al, 2007). Figueredo et al (2013) reported low MICs for ketoconazole and itraconazole, with higher MICs for ketoconazole.…”

Section: Discussionsupporting

confidence: 86%

“…Common treatments for Malassezia dermatitis and otitis include antifungal agents like polyenes, azoles, allylamines or chlorhexidine. Antifungals belonging to the azole group are one of the most effective and the most frequently used drugs in the management of the infection, ketoconazole and itraconazole being the most active against this microorganism with very low MICs (Brito et al, 2007;Bond, 2010;Jesus et al, 2011;Jerzsele et al, 2013). However, yeasts including malasseziae can produce biofilms in vitro (Cannizzo et al, 2007;Figueredo et al, 2012), decreasing susceptibility to the antimicrobial drugs used.…”

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confidence: 99%

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Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Jerzsele

Gyetvai²,

Csere³

et al. 2014

Acta Veterinaria Hungarica

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Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to antimicrobial drugs. The aim of this study was to determine and compare the in vitro susceptibility of planktonic cells and biofilms of M. pachydermatis isolates to ketoconazole and itraconazole. The presence of biofilm formation was confirmed by crystal violet staining and absorbance measurement at 595 nm wavelength, and by a scanning electron microscopy method. Cell viability was determined by the Celltiter 96 Aqueous One solution assay containing a water-soluble tetrazolium compound (MTS) with absorbance measurement at 490 nm. Planktonic cell minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of ketoconazole and itraconazole were very low: MIC 90 and MFC 90 were 0.032 and 0.125 µg/ml for ketoconazole, while 0.063 and 0.25 µg/ml for itraconazole, respectively. Also, the half maximal effective concentrations (EC 50 ) of itraconazole were higher for planktonic cells and biofilms compared to ketoconazole. The EC 50 values of ketoconazole were 18-169 times higher and those of itraconazole 13-124 times higher for biofilms than for planktonic cells. Biofilm EC 50 levels exceeded MICs 103-2060 times for ketoconazole and 84-1400 times for itraconazole. No significant difference was found between these values of the two substances. In conclusion, biofilms of all examined M. pachydermatis strains were much less susceptible to ketoconazole and itraconazole than their planktonic forms. Key words: Biofilm, itraconazole, ketoconazole, Malassezia pachydermatis, planktonicMalassezia pachydermatis is a frequently isolated commensalistic yeast in veterinary dermatology (Bond, 2010;Outerbridge, 2006). It is a member of the normal skin flora, but can cause secondary dermatitis or external otitis in dogs and

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Section: Discussionsupporting

confidence: 86%

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confidence: 99%

Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Jerzsele

Gyetvai²,

Csere³

et al. 2014

Acta Veterinaria Hungarica

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“…One possibly resistant isolate of M. pachydermatis to the antifungals ketoconazole and itraconazole was also described [7]. In vitro cross-resistance of Malassezia among azoles was observed [8]. In human medicine, general emergence of antifungal resistance is already known [9].…”

Section: Introductionmentioning

confidence: 99%

Antifungal in vitro Activity of Essential Oils against Clinical Isolates of <b><i>Malassezia pachydermatis</i></b> from Canine Ears: A Report from a Practice Laboratory

et al. 2019

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Background: The yeast Malassezia pachydermatis is a commensal but also the most isolated pathogenic yeast in canine otitis externa. Essential oils (EOs) exhibit antimicrobial activity and thus could be an alternative for treatment of otitis. Objective: The aim of this study was to analyse the in vitro efficacy of EOs against M. pachydermatis isolates from canine ears. Materials and Methods: Twenty-two EOs were tested for their in vitro activity against 15 M. pachydermatis isolates by agar disc diffusion. In addition, diluted EOs were tested and volatile antifungal activity was analysed by vapour assay. Results: Most EOs showed in vitro efficacy against M. pachydermatis. A different susceptibility pattern of tested isolates was found. Overall, the most potential EO was lemon grass. Also, cinnamon leaf, clove, manuka, Indian melissa, oregano, palmarosa, and winter savory oil exhibited a strong antifungal activity. Volatile activity was proven by the inhibiting effect in vapour assay. Conclusion: EOs show in vitro activity against M. pachydermatis. This study gives scientific background for the use of EOs in veterinary medicine. Diverse susceptibility patterns of different M. pachydermatis strains emphasise the helpfulness of an aromatogram as one lead for the best choice of an EO for therapy. Antimykotische In-vitro-Wirksamkeit ätherischerÖle gegen Malassezia pachydermatis isoliert aus Hundeohren: Ein Bericht aus dem Routinelabor Schlüsselwörter Ätherische Öle · Malassezia pachydermatis · Otitis externa · Veterinärmedizin Zusammenfassung Einleitung: Der Hefepilz Malassezia pachydermatis gilt als Kommensale, ist aber gleichzeitig auch der am häufigsten isolierte Hefepilz bei caniner Otitis externa. Ätherische Öle könnten aufgrund ihrer antimikrobiellen Eigenschaften als alternative Therapie der Otitis verwendet werden. Zielsetzung: Ziel dieser Studie war die Untersuchung der antifungalen In-vitro-Wirksamkeit ätherischer Öle gegen M. pachydermatis-Isolate aus Hundeohren. Material und Methoden: Die In-vitro-Aktivität von 22 ätherischen Ölen wurde mittels Agar-Plättchen-Diffusionstest gegen 15 M. pachydermatis-Isolate untersucht. Zusätzlich wurden Verdünnungen der ätherischen Öle getestet und die volatile Wirkung mittels "vapour assay" analysiert. Ergebnisse: Die meisten ätherischen Öle zeigten in vitro eine Wirksamkeit gegen M. pachydermatis. Es konnte eine unterschiedliche Empfindlichkeit einzelner M. pachydermatis-Isolate gefunden werden. Lemongrasöl erwies sich als das po-tenteste ätherische Öl. Ebenfalls zeigten Zimtblätter-, Nelken-, Manuka-, indisches Melissen-, Oregano-, Palmarosa-und Bergbohnenkrautöl eine starke antifungale Wirksamkeit. Die volatile Wirkung konnte mittels "vapour assay" gezeigt werden. Schlussfolgerung: In vitro zeigen ätherische Öle eine Wirksamkeit gegen den Hefepilz M. pachydermatis. Diese Studie bietet eine wissenschaftliche Basis zur Anwendung ätherischer Öle in der Veterinärmedizin. Die unterschiedliche Empfindlichkeit der verschiedenen M. pachydermatis-Isolate gegenüber einzelner äther...

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“…Fluconazole resistance has been described previously as Eichenberg et al (2003) observed fluconazole resistance in 2.4% of the 82 isolates tested. Further, Jesus et al (2011) induced resistance to fluconazole in vitro , demonstrating that M. pachydermatis isolates can become resistant during treatment with this antifungal. Bernardo et al (1998) found a M. pachydermatis isolate that was resistant to several antifungals, including amphotericin B, nystatin and miconazole.…”

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confidence: 99%

Susceptibility variation of Malassezia pachydermatis to antifungal agents according to isolate source

Weiler¹,

Jesus²,

Nardi³

et al. 2013

Braz. J. Microbiol.

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In vitro susceptibility of fluconazole-susceptible and -resistant isolates of Malassezia pachydermatis against azoles

Cited by 56 publications

References 18 publications

Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Antifungal in vitro Activity of Essential Oils against Clinical Isolates of <b><i>Malassezia pachydermatis</i></b> from Canine Ears: A Report from a Practice Laboratory

Susceptibility variation of Malassezia pachydermatis to antifungal agents according to isolate source

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