Granulomatous dermatitis due to Corynebacterium mucifaciens in a heifer

The skin is a major constituent of the immune system in all mammals and nondiphtheria corynebacteria maybe contaminant of normal skin flora and agents of disease both in humans and animals. In bovines, nondiphtheria coryne-bacteria are involved in clinical or subclinical mastitis cases, pyogranulomatous reactions, abscess formation, ulcerativelymphangitis, mastitic and visceral forms and ulcerative-granulomatous dermatitis.Aim- In this paper, the authors describe the morpho-pathological and etiopathogenetic aspects of a unique case of granulo-matous dermatitis, occasionally found in a heifer, due to an infectious agent so far never reported in veterinary medicine.Material and methods- A 2 y.o. Italian Friesian heifer, belonging to an intensive farming, showed a papillomatous-likeexophytic lesion at the edge of the right auricular pinna. The lesion appeared firm, irregularly globular in shape, 9x11.5 cmin size, with depigmented and ulcerated skin remnants. The lesion was cytologically examined, surgically removed and hi-stologically studied. In addition, the molecular biology examination was performed by means of Polymerase Chain Reac-tion (PCR).Results- Cytological and histological examinations allowed the diagnosis of a pyogranulomatous inflammation. Histochemi-cal stains highlighted numerous coccoid formations within the piogranulomatous reaction or freely standing in the tissue as-sociated with a Splendore-Hoeppli phenomenon. PCR confirmed them belonging to the species Corynebacterium mucifaciens.Discussion-Corynebacterium mucifacienshas been described, to date, only in humans, where it has been related to severe in-fections, lethal bacteremia, otitis and nasal polips, cavitary pneumonia, corneal ulcer. Corynebacterium mucifaciens is a recen-tly described species belonging to the group nondiphtheria Corynebacterium, has been recognized as important human op-portunistic pathogen in immunocompromised or severely-ill patients and it has been isolated from human blood or other nor-mally-sterile body fluids and from wound swab.Conclusions- The presented case describes an extremely unusual site-lesion for the bovine species and this is the first reportin veterinary medicine of a case of Corynebacterium mucifaciensinfection in animals, strongly suspected to have a role as zoo-notic agent