High multi-azole-resistant Malassezia pachydermatis clinical isolates from canine Malassezia dermatitis.

Malassezia pachydermatis, a lipophilic and aerobic yeast, is a causative agent of Malassezia dermatitis, a common skin mycosis in dogs and cats. This fungus is also responsible for zoonotic fungal infections in human neonates. Ravuconazole (RVZ) is an antifungal azole compound and the active metabolite of fosravuconazole, which was approved for use in humans in Japan in 2018. In the present study, in vitro RVZ susceptibility and multi-azole resistance of 13 clinical M. pachydermatis strains was investigated using the modified Clinical and Laboratory Standards Institute M27-A3 test. The minimum inhibitory concentrations (MICs) for the 13 isolates ranged from 0.094 to >32 mg/L for itraconazole (ITZ) and from 0.5 to >32 mg/l for RVZ. Similarly, MICs for ITZ- or RVZ-resistant strains (MICs >32 mg/l) were also >32 mg/l for clotrimazole (CTZ), >32 mg/l for miconazole (MCZ), and 0.25 to >32 mg/L for voriconazole (VRZ). BLAST analysis using the NCBI database showed that ERG11 cDNA of the RVZ-resistant strain encoded Gly at codon 461 and Asp in cytochrome p450 encoded by M. pachydermatis ERG11 mRNA. This work is the first report to describe that an RVZ-resistant M. pachydermatis strain contains ERG11 mutations. The affinity of the protein encoded by ERG11 for RVZ may differ from that of ITZ. Therefore, RVZ has considerable therapeutic potential for treating ITZ-resistant canine Malassezia dermatitis. However, RVZ-resistant strains already exist in canine Malassezia dermatitis in Japan.

Multi-azole-resistant strain of Malassezia pachydermatis isolated from a canine Malassezia dermatitis.

In the case presented here, we describe the isolation of an azole-resistant strain of M. pachydermatis from a canine Malassezia dermatitis. The isolate (NUBS18001) from this case exhibited a minimum inhibitory concentration (MIC) of 320 µg/ml to itraconazole (ITZ) by broth microdilution (BM) assay, >32 µg/ml to ITZ by E-test, and >32 µg/ml to KTZ by E-test. Synergistic effects between FK506 and ITZ in the azole-resistant strain was evaluated using the microdilution checker-board method. The ITZ-resistant strain exhibited MICs of 320 µg/mL of ITZ alone and 5 µg/ml of FK506 alone; the addition of FK506 attenuated the ITZ MIC to 2.5 µg/ml, yielding an ITZ FICI value of 0.507. This result suggested that the combination of ITZ and FK506 exerted an additive effect against the ITZ-resistant strain. To understand the other mechanism inferred to be present in our multi-azole-resistant strain, we sequenced the ERG11 gene from this isolate, and detected missense mutations (A412G and C905T) in the sequence of the ERG11 open reading frame (ORF). To the best of our knowledge, this work is the first report that a multi-azole-resistant M. pacydermatis strain contains mutations in ERG11.

Profiling of serum metabolites in canine lymphoma using gas chromatography mass spectrometry.

Canine lymphoma is a common cancer that has high rates of complete remission with combination chemotherapy. However, the duration of remission varies based on multiple factors, and there is a need to develop a method for early detection of recurrence. In this study, we compared the metabolites profiles in serum from 21 dogs with lymphoma and 13 healthy dogs using gas chromatography mass spectrometry (GC-MS). The lymphoma group was separated from the control group in an orthogonal projection to latent structure with discriminant analysis (OPLS-DA) plot using ions of m/z 100-600, indicating that the metabolites profiles in lymphoma cases differed from those in healthy dogs. The lymphoma group was also separated from the control group on OPLS-DA plot using 29 metabolites identified in all serum samples. Significant differences were found for 16 of these metabolites with higher levels in the lymphoma group for 15 of the metabolites and lower levels for inositol. An OPLS-DA plot showed separation of the lymphoma and healthy groups using these 16 metabolites only. These results indicate that metabolites profile with GC-MS may be a useful tool for detection of potential biomarker and diagnosis of canine lymphoma.

Fibrodysplasia ossificans progressiva in a Maine Coon cat with prominent ossification in dorsal muscle.

A one-year and six-month-old female Maine Coon cat presented with skin problems and paravertebral induration with a history of seven months. Survey radiographs and computed tomography revealed prominent calcifications in both sides of cervical, thoracic and lumbar vertebrae and soft tissue in femoral regions, below knee regions and in brachial regions. Histopathological findings from muscle biopsy samples showed connective tissue proliferation around adjacent skeletal muscle, cartilage formation and endochondral ossification. On the basis of these findings, this feline patient was diagnosed with fibrodysplasia ossificans progressiva (FOP). The most prominent signs observed in this FOP case were significant calcifications of dorsal muscle and presentation of cutaneous signs at the early stage.