A 3 y.o. German Shepherd dog (GSD) was received for necropsy examination. The euthanized dog had originally presented with anorexia and general pain, more specifically in the cervical and lumbar regions of the spine. Differential diagnosis was originally was fungal (suspect Aspergillus sp) discospondylitis, or trauma or disc extrusion, however Aspergillus titres were negative.
The major finding at post mortem was pyogranulomatous discospondylitis at C5-C6. Exudate from this site showed the presence of neutrophilic and histiocytic inflammation and the presence of fungal hyphae. Similar inflammatory lesions in multiple organs along with the presence of intra-lesional fungal hyphae were suggestive of disseminated Aspergillosis.
Kidney and pus extruded from the spine at the C5-C6 inter-vertebrate space were received for bacterial and fungal culture.
No bacterial growth was obtained from the kidney and pus extruded from the spinal column after 4 days incubation However, within 4 days an olive – brown cottony mould-like growth had appeared on all Sabourauds media. Microscopy showed the presence of septate hyphae with oval conidia in long chains. The isolate was submitted to the National Mycology Reference Laboratory in Adelaide and was subsequently identified as Paecilomyces variotii a common environmental mould similar and closely related to the genus Penicillium. The organism has been isolated from human cases of keratitis and cellulitis often associated with indwelling catheters. It has also been isolated from the spinal column of GSD but not before in Australia. Foley et al (2002) reviewed the reporting of Paecilomyces in dogs in the U.S. between 1980-2000. German shepherd dogs and especially female GSD were over represented but the exact nature of the breed and gender differences is not clear.
Paecilomyces, like Penicillium are usually regarded as contaminant moulds. These finding suggest that this is not the case where discospondylitis is apparent in dogs.