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Background Staphylococcus pseudintermedius is the leading cause of pyoderma in dogs and the frequent use of antimicrobial treatment is associated to the development of resistance to nearly all classes of antibiotics. Despite S. pseudintermedius significance, our understanding of the molecular mechanism of β-lactam resistance and its genetic diversity remains limited. We aimed to: i ) determine the phenotypic resistance profile of methicillin resistant Staphylococcus pseudintermedius (MRSP) isolated from infected dogs in three different veterinary hospitals in Buenos Aires, Argentina; ii ) identify the SCC mec elements and resistance genes; and iii ) analyze the clonal relationship between isolates and in regard of dominant lineages found in the world. Results In addition to the differential levels of β-lactam resistance, MRSP isolates ( n = 10) showed resistance to 5–6 families of antibiotics, and were therefore categorized as multidrug-resistant. All the isolates were variant of SCC mec V homologous to S. aureus ; additional SCC mec Finder analysis classified five of the genomes as SCC mec type V (5C2&5) with mecA (encodes for PBP2a) , mecRI and mecI and all the genes closely related to the reference SCC mec type V S. aureus TSGH17 strain. In the remaining five strains, mecA was present, although other genes associated with SCC mec V including mecR1 and mecI were missing. PBP2a was inducible in low level resistance strains (MRSP 8151), and constitutively expressed in MRSP 8150, suggesting different mecA regulatory mechanisms. MRSP isolates showed significant genetic diversity: eight PFGE clonal types and six multilocus-sequence typing (MLST) sequence types (STs) (339, 649, 919, 920, 921 and 922), including four new STs genetically distinct from STs reported in other geographic areas. Comparative genomics and phylogenetic analyses of the MRSP showed a correlation between the genetic content and the phenotypes, and established the genetic relationship between the isolates. Conclusions MRSP could be a threat to animal health due to it concerning level of antimicrobial resistance. Our study highlights genetic and epidemiological aspects of multidrug-resistant MRSP strains from Argentina showing high degree of correlation between the resistance genes and the phenotype of the isolates and, furthermore, they appeared evolutionary closer to major worldwide reported ST68 and...

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A 2-year-old female Border collie was examined for dermatitis with a partial alopecic zone around her left front member. Six months later the lesion became swollen, alopecic with ulcerated areas. Microscopy analysis of samples showed numerous non-septate, branching, thin-walled and irregular shaped hyphal elements. Fungal cultures and molecular studies identified Saksenaea vasiformis. Treatments with griseofulvin, itraconazole and surgical debridement were used, however, fourteen months later the dog was euthanatized because of the unfavorable clinical outcome.