Naslov
Screening of antifungal susceptibility of Malassezia pachydermatis isolates from dogs using disk diffusion test

Autori
Hađina, Suzana ; Benvin, Iva ; Štritof, Zrinka ; Habuš, Josipa ; Stevanović, Vladimir ; Perharić, Matko ; Martinković, Krešimir ; Mojčec Perko, Vesna ; Barbić, Ljubo ; Milas, Zoran ; Satrešina, Vilim ; Turk, Nenad ; Pinter, Ljiljana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
9th Trends in Medical Mycology Held on 11–14 October 2019, Nice, France, Organized under the Auspices of EORTC-IDG and ECMM / Gangneux, Jean-Pierre ; Lortholary, Olivier ; Cornely A., Oliver ; Pagano, Livio - Nica, 2019, 136-137

Skup
9th Trends in Medical Mycology

Mjesto i datum
Nica, Francuska, 11.10.2019. - 14.10.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
antifungal susceptibility, Malassezia pachydermatis, dogs, disk diffusion test

Sažetak
Objectives: Malassezia pachydermatis is lipophilic yeast commonly seen in skin and ear diseases of dogs. Lately, different studies are describing the appearance of reduced susceptibility of M. pachydermatis strains. In addition, reports about its zoonotic potential and emerged number of Malassezia yeast resistance in human medicine, highlight the need for study of its antifungal susceptibility. The problem of surveillance of potential resistance is lying in no established reference method for antifungal susceptibility testing and no interpretative criteria for this yeast. Various studies used different methodologies and interpreted obtained results based on different recommendations. Modified microdilution method is considered the most accurate, but at the same time more expensive and technically demanding to perform in clinical laboratories. Recent study demonstrated good correlation of results obtained by modified CLSI M44-A2 disk diffusion and broth microdilution method, indicating its suitability for in vitro susceptibility testing of M. pachydermatis in epidemiological studies (Pasquetti et al., 2015.). The aim of this study was to screen antifungal susceptibility of M. pachydermatis for miconazole (MCZ) and clotrimazole (CTZ) using disk diffusion method. Methods: A total of 96 isolates of M. pachydermatis were recovered from animals with clinical signs of otitis. Identification was based on their ability to grow on Sabouraud dextrose agar and typical macroscopic and microscopic appearance. Two antifungal tablets containing most commonly azole derivatives used for topical therapy were tested: MCZ and CTZ (10 μg, Neo-Sensitabs, Rosco, Denmark). Disk diffusion test was performed using Mueller- Hinton agar supplemented with 2% glucose and 0.5 μg/l methylene blue. Inoculum of M. pachydermatis was prepared in sterile saline from 3 days old cultures, with addition of the lipid source, containing approximately 1-5x107 CFU/mL. Readings were performed 72 hours after incubation at 37°C, and interpreted according to guidelines provided by manufacturer. Results: Out of 96 tested, all isolates demonstrated good susceptibility to CTZ with variations of inhibition zones from 34 to 73 mm (mean ± SD: 56 ± 8, 06 mm). Susceptibility testing against MCZ resulted with the range of inhibition zones from 14 to 65 mm (mean ± SD: 41 ± 6, 77 mm) and good sensitivity of 95 strains, while one isolate demonstrated intermediate sensitivity. Comparison of the size of the zones showed that CTZ had larger zones of inhibition than MCZ indicating its higher antifungal activity. Conclusion: Screening of antifungal susceptibility of M. pachydermatis using disk diffusion method resulted with identification of one strain with reduced susceptibility to MCZ. However, taking into consideration that there are no standardized interpretative criteria for Malassezia yeast, follow up study using broth microdilution assay is needed, in order to check if this isolate could be categorized as potentially resistant.

Izvorni jezik
Engleski

Znanstvena područja
Veterinarska medicina

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