Scanning electron microscopy and fungal culture of hoof horn from horses suffering from onychomycosis

New methods for isolation of keratolytic bacteria inducing intractable hoof wall cavity (Gidoh) in a horse; double screening procedures of the horn powder agar-translucency test and horn zymography

To establish a new system to isolate keratolytic bacteria from the hoof wall cavity (Gidoh) of a racehorse, we invented the horn powder agar-translucency (HoPAT) test and horn zymography (HZ). Using routine bacteriological techniques and these methods, we isolated five strains of keratolytic soil bacteria, which were then identified by means of 16S ribosomal RNA (rRNA) gene sequencing analysis. The findings from the study on the horse suggested that Brevibacterium luteolum played the main role in the local fragility of the hoof, eventually forming a Gidoh in coordination with four other strains of keratolytic bacteria. The double screening procedures of the HoPAT test and HZ were useful and easy techniques for isolating the keratolytic bacteria from the horn lesions.

Non-dermatophyte Dermatoses Mimicking Dermatophytoses in Animals

Dermatophytoses in animals are fungal diseases of the skin caused by dermatophyte fungi of the genus Microsporum or Trichophyton. Because the infection is generally follicular, the most common clinical sign is one or many circular areas of alopecia with variable erythema, scaling and crusting, and the primary differential diagnoses are follicular infections, such as bacterial folliculitis and demodicosis. Although dermatophyte folliculitis or ringworm is the most commonly observed lesion of dermatophytoses in animals, other presentations may be observed according to the host species and the dermatophyte involved: dermatophyte folliculitis or ringworm, scaling and crusting in dermatophytosis due to Microsporum persicolor, nodule in case of kerion or mycetoma, matted hairs, seborrheic dermatosis or miliary dermatitis in cats, generalized exfoliative dermatoses in dogs, cats and horses, superficial non-follicular pustules, papules and macules in the Devon Rex cat, pruritic dermatophytoses in dogs, cats and horses, and onychomycosis in dogs, cats and horses. Since manifestations of dermatophytosis are highly variable, particularly in the cat, dermatophytosis should be considered in case of any annular, papular, nodular or pustular dermatoses, alopecic or not, sometimes pruritic, and nodular dermatoses as well.