Granulomatous lesions caused by Pseudomonas aeruginosa in the ostrich (Struthio camelus)

Granulomatous lesions were observed in imported ostriches aged 3 months. Clinically, the birds showed lassitude, incoordination, and inappetence. At necropsy, yellowish white nodules often accompanied by a pseudodiphtheritic membrane were found in the oral, pharyngeal, tracheal and air sac mucosae, the lungs, oesophageal serosa, and abdominal peritoneum. Histopathological examination revealed purulent granulomatous lesions containing central bacterial colonies with an outer shell and club formation. The bacteria were small Gram-negative bacilli, which showed positive immunohistochemical staining for Pseudomonas aeruginosa. The bacterial colonies were positive for chicken IgM. Clubs around the colonies were negative for P. aeruginosa and chicken IgM. Such findings have not previously been reported in the ostrich.