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Background: The genus Corynebacterium comprises well-known animal and human pathogens as well as commensals of skin and mucous membranes. Species formerly regarded as contaminants are increasingly being recognized as opportunistic pathogens. Corynebacterium oculi has recently been described as a human ocular pathogen but has so far not been reported in dogs., Case Presentation: Here we present two cases of infection with a novel Corynebacterium sp., a corneal ulcer and a case of bacteriuria. The two bacterial isolates could not be identified by MALDI-TOF MS. While 16 S rRNA gene (99.3% similarity) and rpoB (96.6% identity) sequencing led to the preliminary identification of the isolates as Corynebacterium (C.) oculi, whole genome sequencing revealed the strains to be closely related to, but in a separate cluster from C. oculi. Antimicrobial susceptibility testing showed high minimal inhibitory concentrations of lincosamides, macrolides, tetracycline, and fluoroquinolones for one of the isolates, which also contained an erm(X) and tet-carrying plasmid as well as a nonsynonymous mutation leading to an S84I substitution in the quinolone resistance determining region of GyrA., Conclusions: While the clinical signs of both dogs were alleviated by antimicrobial treatment, the clinical significance of these isolates remains to be proven. However, considering its close relation with C. oculi, a known pathogen in humans, pathogenic potential of this species is not unlikely. Furthermore, these bacteria may act as reservoir for antimicrobial resistance genes also in a One Health context since one strain carried a multidrug resistance plasmid related to pNG3 of C. diphtheriae., (© 2023. The Author(s).)

Fifteen English cocker spaniels with confirmed vitamin E deficiency were examined physically, ophthalmologically and neurologically. Eleven of them had clinical signs of neurological dysfunction which included ataxia, proprioceptive deficits, abnormal spinal reflexes and muscle weakness. In the two dogs examined histopathologically there was central neuronal fibre degeneration with prominent neuroaxonal dystrophy, particularly within the sensory relay nuclei of the brainstem, and one of the dogs had severe intestinal lipofuscinosis.

The role of vitamin E deficiency in the development of retinal pigment epithelial dystrophy was investigated in 11 cocker spaniels and four other dogs. The concentration of alpha-tocopherol was measured by high performance liquid chromatography in plasma samples obtained from the affected dogs and from 28 ophthalmoscopically normal, healthy control dogs. The mean (sd) plasma alpha-tocopherol concentration in the normal dogs was 20.2 (7.1) microg/ml, compared with 1.14 (0.67) microg/ml in the 11 affected cocker spaniels. The difference between the two groups remained highly significant when the alpha-tocopherol concentrations were expressed relative to the concentrations of the plasma lipids cholesterol and triglycerides. Low plasma concentrations of alpha-tocopherol were observed in the four affected dogs of other breeds, but the finding was not so consistent. The plasma lipid concentrations were normal in the affected dogs. The deficiency of alpha-tocopherol in the affected dogs appeared to be primary, because there was no clinical, biochemical or pathological evidence of underlying disease, or any indication of a dietary deficiency which might have contributed to the low concentrations of alpha-tocopherol.