Genotyping and antifungal susceptibility testing of multiple Malassezia pachydermatis isolates from otitis and dermatitis cases in pets: is it really worth the effort?
A total of 216 colonies of Malassezia pachydermatis from 28 cases of fungal otitis or dermatitis in pets were genotyped by M13 fingerprinting and tested for antifungal susceptibility. A huge genetic diversity was found (157 M13 types in total), with all animals having a polyclonal pattern of infection (5.4 ± 1.5 genotypes/sample). Furthermore, analysis of molecular variance (AMOVA) revealed that most genetic diversity (44%) was found at the within sample level. In contrast, variability in antifungal susceptibility among isolates from the same sample was less important, with different M13 types displaying in most cases identical or very similar MIC results. Most isolates displayed high in vitro susceptibility to amphotericin B, terbinafine and all azoles tested except fluconazole, for which MIC values were always ≥4 μg/ml and a 26.9% of isolates displayed values ≥32 μg/ml. We conclude that although characterization of multiple yeast isolates results in a considerable increase in laboratory workload and expenses, it may help to get a better understanding of the epidemiology of M. pachydermatis in a given patient population.
Department of Animal Health, Faculty of Veterinary, Universidad Complutense de Madrid, Madrid, Spain.
Sergio
S
Álvarez-Pérez
Department of Animal Health, Faculty of Veterinary, Universidad Complutense de Madrid, Madrid, Spain.|Veterinary Hospital, UCM, Madrid, Spain.
Marta E
ME
García
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.|Department of Medicine, Faculty of Medicine, Universidad Complutense de Madrid, Madrid, Spain.
Teresa
T
Peláez
Department of Animal Health, Faculty of Veterinary, Universidad Complutense de Madrid, Madrid, Spain.|Veterinary Hospital, UCM, Madrid, Spain.
José L
JL
Blanco
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D016172:DNA Fingerprinting; D003881:Dermatomycoses / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D025141:Drug Resistance, Fungal; D014644:Genetic Variation; D005838:Genotype; D060005:Genotyping Techniques; D008290:Malassezia / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D010031:Otitis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D057805:Pets
D000935:Antifungal Agents
Malassezia pachydermatis; antifungal susceptibility; dermatitis; genotyping; otitis; pets