Pyogenic Ventriculitis and Ventricular Empyema associated with Staphylococcus pseudintermedius in a Puppy

A 40-day-old male, blue heeler puppy with hindlimb ataxia, nystagmus, apathy, motor incoordination and hyperaesthesia of the forelimbs died 3 days after the onset of clinical signs. Significant gross findings included cerebellar herniation, cerebral oedema and dilation of the third and right lateral cerebral ventricles due to the accumulation of a purulent exudate. Histopathological examination revealed pyogenic ventriculitis and purulent meningoencephalitis. Pure colonies of a coagulase-positive Staphylococcus were isolated from the purulent cerebral exudate. A polymerase chain reaction assay that targeted the 16S rRNA gene of bacteria amplified the desired product from bacterial colonies. Direct sequencing revealed the organism to be Staphylococcus pseudintermedius. Phylogenetic analyses showed that the organism was antigenically similar to Staphylococcus intermedius and Staphylococcus delphini, being part of the S. intermedius group of bacteria. These findings confirmed the participation of S. pseudintermedius in the development of the pathological manifestations and lesions observed in this puppy.