ABSTRACT
This study aims to examine the effectiveness of mycocins produced by Wickerhamomyces anomalus in inhibiting Malassezia pachydermatis, a yeast commonly found in the ear canal of dogs. M. pachydermatis has a zoophilic origin and can be found in mammals, and frequently in dogs, where it mainly colonizes the ear canal region and the skin, leading to lesions that are difficult to treat. The antimicrobial mechanism was evaluated using dilutions of supernatant with enzymatic activity, which may include ß-glucanases, glycoproteins known to act on microorganism cell walls. However, it is important to note that this supernatant may contain other compounds as well. ß-glucanases in the mycocins supernatant were found at a concentration of 0.8 U/mg. The susceptibility of M. pachydermatis isolates was tested using the microdilution method. The isolates suffered 100% inhibition when tested with the culture supernatant containing mycocins. In the proteinases production test, 44% of the isolates tested were strong proteinases producers. Subsequently all these isolates suffered inhibition of their activity when tested in research medium containing mycocins supernatant at a subinhibitory concentration of ß-glucanases. This shows that mycocins can inhibit the production of proteinases, a virulence factor of M. pachydermatis. The viability test showed the antifungal action of mycocins in inhibiting the viability of M. pachydermatis cells after a period of 8 hours of contact. These results support the antimicrobial potential of mycocins and their promise as a therapeutic option.
ABSTRACT
Cryptococcosis is a mycosis caused by yeasts of genus Cryptococcus, mainly the species C. neoformans and C. gattii that can affect humans and animals. These yeasts are widely distributed in the environment and are typically associated with avian droppings and decaying wood. Most infections are related to the respiratory tract, but the central nervous system and cutaneous lesions are also reported in the literature. The present report is a case of cryptococcosis in an 18-month-old unspayed female English Bulldog with the main complaint of weight loss and diarrhea. The presence of two large masses observed in an ultrasound examination leads us to perform an exploratory laparotomy. Considering the size of the lesion and the impossibility of owner to provide intensive care, the consent for euthanasia was requested. The postmortem diagnosis of cryptococcosis was revealed by cytological evaluation, and the involvement of C. gattii VGII was confirmed by isolation and identification tests as well as by the detection of the URA5 gene restriction fragment length polymorphism PCR analysis. Reports in the literature of the involvement of Cryptococcus in gastrointestinal lesions are rare in both human and veterinary medicine. Data about different forms of cryptococcosis are important to provide more knowledge of uncommon clinical presentations of this yeast and therefore improve the diagnoses and decisions for the best therapy.
